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Induced pain : cognitive and behavioural correlates Aquan-Assee, Jasmin Soylin Elizabeth 1988

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INDUCED PAIN: COGNITIVE AND BEHAVIOURAL CORRELATES BY JASMIN SOYLIN ELIZABETH AQUAN-ASSEE B.Sc.(Hons.) McGill University, 1985 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in THE FACULTY OF GRADUATE STUDIES Department of Psychology We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA JUNE 1988 (c) Jasmin S.E. Aquan-Assee, 1988 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of P s y c h o l o g y The University of British Columbia Vancouver, Canada Date J u n e 1988 DE-6 (2/88) A b s t r a c t Cognitive processes have recently received considerable attention in studies of pain. Belief systems, coping mechanisms, perceptions of control and self-efficacy, and other cognitive systems appear to play a central role in determining individual differences to painful events (Rollman, 1983; Turk, Meichenbaum & Genest, 1983; Weisenberg, 1984). The present investigation sought to examine the cognitive and behavioural relationships that are associated with individual differences in responses to painful stimuli. Sixty female undergraduate psychology students participated in the experimental pain induction procedure which used the cold pressor test as the noxious stimulation. To gain a broad assessment of the different factors that may be characteristic of differences in response to pain, tolerant subjects were contrasted with less tolerant subjects on a variet3' of self-report, cognitive and behavioural - facial expression - measures. As part of the assessment procedure, subjects completed measures of state anxiety, self-efficacy to withstand pain, and a questionnaire involving a retrospective analysis of cognitive techniques. Half of the subjects were interviewed regarding their cognitions concerning the cold pressor task both pre and post their immersion, and the other half were interviewed post only. Transcriptions were coded independently of pain tolerance status. Subjects' facial expressions were videotaped during the cold pressor task and coded using the Facial Action Coding System (FACS) developed by Ekman and Friesen (1978). It was hypothesized that dysfunctional cognitions, lack of effective coping activity, amplification of sensory intensity and affective discomfort and high levels of facial activity would characterize subjects who were less tolerant of the induced pain. The distribution of the endurance times to the cold pressor task confirmed past observations that subjects cluster into two major groups of high and low tolerance (Turk et al. 1983). The results confirmed the major hypotheses that there are cognitive and self-report differences between pain tolerance groups. In comparison to tolerant subjects, less n tolerant subjects had lower scores of perceived self-efficacy to withstand pain, higher scores for both sensation and discomfort ratings, retrospectively reported having experienced more pain, and made more accurate estimates of their duration in the cold water. Less tolerant subjects also reported more dysfunctional cognitions during the cold pressor task and reported using effective coping techniques to a lesser extent than tolerant subjects. Major differences between the tolerance groups also appeared in the length of post-test interviews. Tolerant subjects had much lengthier interviews at the post-test than less tolerant subjects. A discriminant analysis revealed that self-efficacy beliefs during the experimental task and the length of the post-test interviews were the most important discriminators between the groups. These results highlight the role of cognition in individual differences in pain tolerance. These results also suggest that low pain tolerance subjects may be better conceptualized as being ineffective and overwhelmed in their attempts to cope with pain which supports the current notion that cognitive based therapies may be the key in managing and alleviating pain states. No support was found for the hypothesis that subjects of differing pain tolerance thresholds would be characterized by differences in facial activity. Facial actions associated with pain in the present study were similar with facial expressions in previous studies (cf. Craig & Patrick, 1985; Hyde, 1986; Swalm, 1987). Contrary to previous results (Craig & Patrick, 1985), measures of facial expression increased over exposure time similarly to self-report. High levels of facial expression were associated with low levels of self-report of coping cognitions assessed at the post-test and with shorter post-test interviews. iii TABLE OF CONTENTS Abstract ii Table of Contents iv List of Tables vii List of Figures viii Acknowledgements ix INTRODUCTION 1 LITERATURE REVIEW 4 The Multidimensional Model of Pain 4 Cognition and Pain 5 Classification of Coping Strategies 6 Definitions of Coping 8 Dispositional Approaches to Coping 8 Instructional Cognitive Coping Strategies 9 Spontaneous Coping Strategies 12 Spontaneous Catastrophising Cognitions 14 Anxiety and Self-Efficacy and their Effect on Pain 16 Non-Verbal Expression and Pain 19 Multidimensional Assessment of Pain 20 Pain Sensitivity Self-Report 21 Cognitive Assessment of Pain 22 Non-Verbal Measurement of Pain 25 Experimentally Induced Pain 27 Statement of the Problem 28 Hypotheses 29 M E T H O D 31 Subjects 31 Apparatus and Material 31 Cold-Pressor Test 31 iv Self-Report Measures 32 Videotape Equipment 33 Procedure 34 Cognitive Assessment 35 Coding 36 RESULTS . . 39 Overview of the Statistical Analysis . 39 Group Differences: Subject Characteristics 40 Behavioural Analyses: Facial Expressions Indices . 4 3 Reducing the number of dependent variables 43 Baseline versus Cold-Pressor Exposure . . . 43 Derivation of Facial Activity Score 45 Group Comparisons: Facial Expressivity 47 Facial Pain Activity Measures 47 Individual action Units . 47 Self-Report Measures . 50 Self-Report Measures of Pain Sensitivity 50 Cognitive Measures 53 Structured Interview Schedule For Pain 53 Group Differences: Pre and Post Structured Interviews 55 Coping Strategy Questionnaire Scales 59 Group Differences: Cognitive Measures (CSQ and SISP) 59 Discriminant Function Analysis of Pain Tolerance Group 63 Relationships Among Cognitive Variables and Facial Expression 65 DISCUSSION 67 Self-Report Measures of Pain 67 Cognition and Pain Tolerance 69 Facial Expression of Pain 72 Pain AU Analyses 76 Cognitive Assessment of Pain 84 Conclusions 85 REFERENCES 87 V APPENDICES A. FACS Action Units 97 B. Gracely Rating Scales 98 C. Perceived Self-Efficacy to Tolerate Pain Questionnaire 99 D. Coping Strategy Questionnaire 104 E. Coping Strategy Questionnaire (Adapted) 106 F. Information and Consent Form 109 G. Debriefing Form 110 H. Post-test Questionnaire I l l I. Structured Interview Schedule for Pain 113 J. SISP Scoring key 115 K. ANOVA Summary Table: Facial Pain Activity Measures Across Cold-Pressor Segments 119 L. MANOVA Summary Table: Facial Action Units Across Cold Pressor Segments 120 M. MANOVA Summary Table: Pre and Post Interview Scores 121 N. ANOVA Summary Table: Facial Pain Activity Measures During Initial Nine Seconds 122 v i List of Tables 1. Group Differences of Self-Efficacy and Anxiety Scores 42 2. Action Unit (AU) Categories Remaining After Application of Exclusion Criteria: Mean Frequency of Occurrence for Cold Pressor and Baseline Periods 44 3. Weights Used to Derive the Facial Pain Activity Measure 46 4. Comparisons of Facial Action Units Between Segments 48 5. Group Comparisons of Pain Sensitivity Self-Report Indices 52 6. Correlations Among the Three Measures of Each Cognitive Strategies of the Structured Interview 54 7. Correlations Among Pre and Post Cognitive Strategy Measurement Cluster Scores of the SISP 56 8. Pre and Post Structured-Interview Cognitive Strategy Measurement Scores: Means and Univariate Analyses 57 9. Relationships Between Coping Strategy Questionnaire and Structured Interview Cognitive Categories 61 10. Group Differences Between Coping Strategy Questionnaire and Structured Interview Categories 62 11. Classification of Pain Tolerance Membership with the Discriminant Function 64 12. Relative Ordering of Discriminating Variables 64 13. Correlations Among Cognitive Variables and the Facial Pain Activity Measurement Scores 66 14. Mean Frequency of Occurrence of Action Unit Categories During Initial Nine Seconds of Cold Pressor Exposure 82 vi! List of Figures 1. Cold-Pressor Tolerance Distribution 41 2. Distribution of AU 45 (blink) Over Cold-Pressor Segments 49 3. Group Differences in the Number of Sentences in Pre and Post Structured Interviews 58 4. Facial Pain Activity Indices Over Time . 7 7 5. Sensory Intensity and Affective Discomfort Ratings Over Time 78 v i i i Acknowledgement So many people contributed directly or indirectly to this work. I am very grateful for all of their assistance. First, I would like to thank Dr. Ken Craig for his comments and support for the project. I would also like to thank my research committee, Drs. Eric Eich, and Darrin Lehman, for their valuable advice, comments and confidence in my research abilities especially at the end of this research. Secondly, I would like to thank those people without whose help this project could never have been completed. In particular Brenda Gerhard for coding all those videotapes, and my transcriber and coders for the interviews. A special thanks also should go to Virginia Green and Dr. R. Hakstian for their invaluable statistical advice. Finally, I would like to thank all those people who supported me emotionally at the various "crisis" points of this thesis: my fellow graduate students, Vicki Bakich, my family at the expense of many long distance phone calls, and most of all, Marc Trudel, whose support and unquestioning belief in me was the source of my drive and motivation to complete this work. ix 1 INTRODUCTION Health professionals have long observed the strikingly different levels of discomfort and pain their patients experience in what appear to be comparable medical conditions (e.g., Fordyce, 1976; Hendler, 1974; Main & Waddell, 1982; Sternbach, 1974; Waddell, Bircher, Finlayson & Main, 1984). One explanation for these individual differences is that the experience of pain depends not only on the extent of the tissue damage, but on psychological factors as well. These factors play an integral role in mediating the experience of, and response to, different forms of nociceptive stimulation (Wack & Turk, 1984). This conceptualization of pain as a multifaceted experience modulated by sensory, cognitive, affective and behavioural phenomena has stimulated an increase in research addressing questions concerning the relation between subjective experience and overt expression, the connections between self-report and non-verbal measures of pain, and the role that cognitive factors play in modifying the pain experience (e.g., Barber, Spanos & Chaves, 1974; Craig, 1984; Melzack & Wall, 1983). Recently a cognitive model of pain has proposed that thoughts, interpretations, expectations, and coping self-statements related to the noxious sensory event should be viewed as central to the pain experience. The cognitive model assumes that individual differences are attributable to stable differences in the manner that cognitions can come to enhance, attenuate, or maintain pain and in turn contribute to affective distress (Turk, Meichenbaum & Genest, 1983). Clinical and empirical observations on individual differences in tolerance to aversive stimulation point not only to the key role of the different kinds of coping techniques employed in these situations, which may be differentially effective in altering tolerance and response to discomfort (Meichenbaum & Turk, 1976; Turk, 1978), but also to the role of another cognitive factor labeled "catastrophising". Catastrophising cognitions (e.g., dysfunctional, anxiety-laden cognitions concerning pain) have been linked with coping effectiveness and pain tolerance (Keefe, Caldwell, Queen, Gil, Martinez, Crisson et al, 1987; 2 Reesor & Craig, 1988; Spanos, Radtke-Bodorick, Ferguson, Jones, 1979; Turner & Clancy, 1987). For a complete understanding of the pain experience, it is critical not to ignore how different factors may characterize different pain reactions. An important aspect of the pain experience that has been virtually ignored by researchers studying pain is nonverbal expression. Cognitive differences between individuals are often inferred whereas the individual differences remarked upon by health professionals as problematic are directly observable in behavioural reactions to pain. The latter can be divided into behavioural escape or avoidance and expressive reactions (gross bodily movement and facial expression). The study of facial expression accompanying pain is of both practical and theoretical importance. It has been suggested that nonverbal behaviour may provide accurate information on pain states to supplement self-report, and perhaps, facial expression could even serve as accurate measures of pain in the absence of verbal report (Craig & Prkachin, 1983; LeResche & Dworkin, 1984). A review of the empirical literature indicates that there are distinct and prominent facial expressions of pain which occur with some regularity during noxious stimulation. The primary purpose of the present investigation was to examine the cognitive and behavioural relationship involved in tolerance to a pain induction task. Given the documented clustering of subjects into two tolerance groups on the cold pressor task (e.g. Dworkin, personal communication; Turk et al. 1983), cognitive strategies were examined in volunteer subjects categorized on the extent to which they were minimally or highly reactive to induced pain. It was proposed that dysfunctional cognitive strategies and high facial pain activity would characterize subjects who displayed short endurance times and that cognitions reflecting greater coping and low facial pain activity would be indicative of subjects with greater pain tolerance. 3 Questions have been raised concerning the appropriate methodology for assessing cognition during pain (Genest & Turk, 1981; Nisbett & Wilson, 1977). Although investigators have begun to address some of the issues regarding the validity of assessing cognitive activity (Genest & Turk, 1981; Turk et al. 1983), none of the studies cited directly test the cognitions the person brings to the pain setting. Rather, cognitions are tested retrospectively and are assumed to be representative of the person's cognitive processes prior to and during the pain induction. Past research may have ignored the potential influence the noxious experience and the people's assessment of their own performance may have had in distorting or biasing retrospective reports. Demand characteristics, availability heuristics, and social desirability influences are formidable (Nisbett & Ross, 1980). To address such issues, structured interviews (Turk et al. 1983) allowing the investigator to "catch a glimpse" of the subject's cognitions both prior to and after the noxious stimulation, and a brief questionnaire aimed at assessing the type of cognitive and behavioural activity characteristic of the subject during pain (Rosenstiel & Keefe, 1983), were used to provide convergent information on the role of the cognitive variables under investigation (Merluzzi, Glass & Genest, 1981). 4 LITERATURE REVIEW The Multidimensional Model of Pain Historically, pain has been viewed either as a cognitive/affective phenomenon or a purely sensory phenomenon. For example, Aristotle viewed pain as an emotion and the Stoic philosophers believed that pain could be overcome by rational repudiation through logic and reasoning (cited in Fulup-Miller, 1938). In contrast, Descartes, employing a classic dualistic approach, conceptualized pain as a purely sensory phenomenon, determined exclusively by noxious sensory input (cited in Melzack, 1973). As medical knowledge made rapid advances during the nineteenth and twentieth centuries, sensorj' qualities of pain came to be emphasized with cognitive and affective dimensions relegated to positions of secondary importance. Since then, pain research and management has typically focussed upon sensory-specificity models of pain (Craig, 1984a). There is considerable variability between individuals and across cultures in the expression of pain (Sternbach & Tursky, 1965) and even within individuals from one occasion to the next (Lazarus, 1986). One explanation for this variability is that factors other than sensation play a role in the expression of pain such as: prior experience (Craig, 1980, 1983), self-efficac3^ in controlling pain (e.g., Bandura, 1982), attention paid to the pain, and the perceived personal impact of the pain (Craig, 1984; Melzack & Wall, 1982). Beecher's (1955) observations of soldiers wounded in battle provide a poignant example of the dramatic lack of correspondence between the extent of tissue damage and the amount of pain experienced. Many soldiers did not complain of intense or severe pain despite life-threatening wounds. It was not that they were insensitive to pain, for inept injections of medicines resulted in pain expression. When questioned later about their reactions, the soldiers indicated they were relieved at being able to leave the battlefield. Other researchers (e.g., Fordyce, 1976; Sternbach, 1974) have noted that pain can persist even after medical, surgical or natural tissue repair has been effected. Such observations underscore the point that pain perception is 5 not directly proportional to the nature of the pain stimulus and should be viewed as involving more than just sensory perception. Moreover, the variability in pain expression, both within and between individuals, questions the presumed stability across situations, that is, our thoughts about pain can differ from situation to situation, hence, so can our reactions to pain. The apparent lack of correspondence between tissue damage and pain experience has prompted researchers to explore the impact of "higher-order" cognitive processes on the experience of pain (Turk & Rudy, 1986). Melzack and Wall (1965, 1983) were among the first to propose a multidimensional model of pain (the gate control model) that encompassed sensory-discriminative, motivational-affective, and cognitive-evaluative components. According to their model, it is the interaction of these factors that determines the pain experience. Hence, somatic input, while still a highly salient dimension of pain, now is modified in a complex organization of cognitive, affective, and motivational systems that djmamically interact during any pain experience (Craig, 1984; Turk et al., 1983; Weisenberg, 1987). Recognition of the multidimensional nature of pain and the reciprocal determinism among the components has had profound implications for the development of strategies for pain relief. Many new treatment packages and current research projects have begun to focus on the modulation of cognitive, affective, or behavioural influences to alter the pain experience (e.g., Fordyce, 1976; Turk et al., 1983). Cognition and Pain Cognition has been defined as "a general concept embracing all forms of knowing. It includes perceiving, judging, reasoning and imagining" (Chaplin, 1975, p.94). Beck, Rush, Shaw and Emery (1979) define cognitions as "verbal or pictorial events in one's stream of consciousness, based on attitudes or assumptions (schemas) developed from previous 6 experience" (p.3). Thus, cognitive perspectives emphasize the role of sensory information search, selection, and interpretation in determining the experience of pain. Formulations of illness behaviour, defined by Mechanic (1962) as ways in which given symptoms may be differentially perceived, evaluated, and acted (or not acted) upon by different persons, have focussed on the complex decision processes involved when people become ill. Research with induced pain, following this point of view, has shown that the manipulation of environmental parameters, of which cognitive interpretations or appraisals of pain are presumed to be a function, such as expectancies (Hall & Stride, 1954) and attention (Ahles, Blanchard & Leventhal, 1983), have been found to affect experimental pain tolerance. Dworkin, Chen, LeResche and Clark (1983) have shown that the manipulation of cognitive expectancies can produce both analgesic and hyperalgesic effects after administration of. the same doses of nitrous oxide in response to tooth pulp stimulation. Studies in which subjects perceived thej' could control either the intensity or timing of an aversive stimulus, have demonstrated greater tolerance times to higher intensity shock (Bowers, 1968; Staub, Tursky & Schwartz, 1971), and longer cold pressor exposure (Kanfer & Seidner, 1973) than for those subjects without the perceived control. Coping processes also play an important role in the individual's pain experience. Coping needs to be conceptualized and measured because it is one of the main mediating processes, perhaps the most important one, from the point of view of human functioning under conditions of stress. Classification of Coping Strategies A major difficulty in reviewing the literature on cognitive pain coping strategies is terminological inconsistency (Fernandez, 1986). Several authors have employed different terms in reference to the same strategies. An example is the strategy of isolating and focussing on a non-painful feature of a noxious stimulus (e.g., focussing on the thermal properties of cold pressor pain): Craig et al. (1974) refer to this as "focussed attention", Blitz and Dinner stein (1971) use the term "dissociation". Similarly, what is termed "incompatible 7 imagery" by Beers & Karoly (1979) is labelled "selective attention" by Thelen and Frey (1981), while Spanos et al. (1975) refer to it simply as "a strategy inconsistent with pain". The problems that follow from such inconsistencies suggest the need for a standardized classification system for cognitive strategies. The ability to meaningfully evaluate the comparative effectiveness of different strategies depends on the availability of a standardized scheme. Attempts have been made to classify coping techniques. Folkman and Lazarus (1980) used a conceptual basis to contrast coping strategies obtained from a middle-aged community sample into two main categories: (1) emotion-focused (palliative) coping, referred to thoughts or actions aimed at reducing the emotional impact of the stressor (e.g., relaxation), and (2) problem-focused coping, involved efforts to alter the troubled person-environment relationship by changing some aspect of it (e.g., information seeking). However, individuals use a complex combination of strategy types depending upon the context and how the event is appraised. Thus, the two coping categories are not mutually exclusive (Monat & Lazarus, 1985). Turk, et al. (1983) have proposed two broad classes of pain-related cognitive activity: (1) attempts to cope with the pain experience, and (2) cognitions that worsen the pain experience. Wack and Turk (1984) developed a classification s.ystem to empirically describe the latent dimensions through which subjects perceive coping strategies to differ. Using a multidimensional scaling technique, eight clusters of coping strategies were identified: (1) pleasant imaginings, (2) rhythmic cognitive activity, (3) external focus of attention, (4) pain acknowledgement, (5) dramatized coping, (6) neutral imagining, (7) breathing activity, and (8) behavioural activity. These eight clusters were then grouped into three dimensions of coping strategies: (1) sensation acknowledging, (2) coping relevance, (3) cognitive/behavioural. 8 A fourth classification scheme proposed by Fernandez (1986) offers a hierarchical . nomenclature for the identification of cognitive coping strategies for pain. The distinctions used are primarily nominal. The various cognitive strategies are classified into three broad divisions: (1) imagery, (2) self-statements, and (3) attention-diversion. These in turn are divided into sub-categories each of which is described and illustrated with reference to documented studies. Definitions of Coping There are many definitions of coping in the literature. Pearlin and Schooler (1978) define coping as a behaviour that protects people from being psychologically harmed by problematic social experience. Lazarus and his colleagues define coping as problem-solving efforts made by an individual when the demands faced are highly relevant to one's welfare (that is, a situation of considerable jeopardy or promise), and when these demands tax one's adaptive resources (Lazarus, Averill, & Opton, 1974). A third definition provided by Turner and Clanc3r (1986) incorporates both the sensory and affective components of pain and defines coping as the specific thoughts and behaviours people use to manage their pain or their emotional reactions to their pain. Dispositional Approaches to Coping An approach many investigators of cognitions and pain have relied upon emphasizes consistent patterns or styles of coping. Coping style is defined by Andrew (1970) as each person's characteristic manner of dealing with stress. Some general dispositional variations in cognitive processes have been found to be related to experimental pain tolerance. Greater pain tolerance has been associated with the tendency to intellectualize and actively cope with threatening external stimuli (Davidson & Bobey, 1970), and the tendency to be independent . from external stimulus characteristics (field independent) in making perceptual judgements (Alder, Gervasi, & Holzer, 1973; Alder & Lomazzi, 1973). Among the coping styles identified in the literature, the most commonly used in research, because of its assumed stability in 9 adults, is the dimension of repression-sensitization (Byrne, 1961). Repression (avoidance) has generally been characterized as the tendency to avoid or deny the threatening or emotional aspects of the situation, along with limited use of intellectualizing defenses. In contrast, sensitization (vigilance) would be the tendency to be overly alert to the stressful stimuli of the situation. Sensitizers are people who typically seek, learn and use information in their intellectualizing defenses. Hypervigilant individuals may actively and selectively search for sensations indicative of pain (Chapman, 1978). There is a growing sense of dissatisfaction associated with the classification of individuals according to these dispositional concepts as they do not provide consistent relationships with recovery, adjustment, or exhibition of coping behaviours (Andrew, 1970; Cohen & Lazarus, 1973). Lazarus and his colleagues have argued against the use of dispositional approaches to the assessment of coping because they feel the unidimensionality of most trait measures and constructs does not reflect the multidimensional quality of coping processes (Folkman & Lazarus, 1980; Lazarus et al., 1974). As most of these trait measures are poor predictors of coping processes, Lazarus and his colleagues propose that an alternate area of study to coping styles is the investigation of the strategies employed. Instructional Cognitive Coping Strategies As the role of cognitive factors has assumed a greater importance in research on pain, not surprisingly, covert processes have been described as targets for modification in individuals suffering pain (Turk et al., 1983). Turk defines coping strategies as sets of overt and covert behaviours in which individuals engage, that are under their control, and that are performed specifically to modulate an aversive situation. Two key functions of coping strategies are: (1) to change the problem situation itself, or (2) to control the meaning of the problem situation (Pearlin & Schooler, 1978). However, as some strategies may be maladaptive or ineffective; "relevant" or "irrelevant" (Spanos, Chaves & Horten, 1975), these goals are not always achieved. 10 The interest in the role of coping strategies has resulted in a proliferation of studies that have compared the effectiveness of different coping techniques that subjects employ when confronted with laboratory induced stressors such as the cold pressor test, muscle ischemia, and radiant heat manipulations (Barber & Cooper, 1972; Blitz & Dinnerstein, 1971; Chaves & Barber, 1974; Hackett & Horan, 1980; Kanfer & Goldfoot, 1966; Worthington, 1978). Typically, such studies involve offering groups of subjects different cognitive (e.g., attention focusing, self-instructional) or behavioural (e.g., relaxation) strategies to cope with the intense stimulation. The effectiveness of instructional strategies has been inferred from their ability to significantly alter levels of self-reported stimulus intensity, measures of autonomic responsivity, or subjects' tolerance of nociceptive stimulation in comparison to no-treatment controls or placebo controls. For example, Beers and Karoly (1979) trained subjects in one of four cognitive strategies: rational thinking/compatible imagery, incompatible imagery, and task irrelevant cognition. Subjects participated in a pretest-training-posttest design using the cold-pressor task. Analyses of covariance indicated that cognitive-imaginal strategies facilitated the endurance of pain and raised the self reported threshold from pretest to posttest. No discussion of the possible underlying mechanisms accounting for the group differences was given. Blitz and Dinnerstein (1971) examined the effects of instruction on cold-pressor pain. They found that analgesic suggestions and instructions in cognitive coping strategies increased pain threshold but not pain tolerance. In a third study (Scott & Leonard, 1978), a covert positive reinforcement procedure (i.e., reinterpreting the sensations in a manner incompatible with the experience of pain and then imagining a pleasant reinforcing image) was evaluated against a reinterpretative strategy alone and an expectancy group. Thresholds of subjects trained in the covert reinforcement procedure were raised above thresholds of the other two groups. 11 Cognitive strategies (e.g. reinterpretation of symptoms, distraction or dissociation, self-hypnosis) have recently become increasingly popular in the treatment and management of both acute and chronic pain in clinical settings (Tan, 1982; Turk et al.,1983; Turner & Chapman, 1982). Several studies have evaluated a selection of cognitive and cognitive-behavioural skill treatments with acute and chronic pain conditions in clinical settings. Tan and Poser (1982) evaluated the efficacy of cognitive-behavioural skills training to help adult patients experience less pain during an arthrogram involving painful manipulations of the knee for an X-ray procedure. The results failed to support the efficacy of skills training for the attenuation of clinical pain. Brown (1984) found reduced reported headache activity for those patients taught imagery coping strategies in the treatment of migraine compared to a placebo control group. Similarly, Rybstein-Blinchik (1979) examined the importance of the cognitive factor in the expression of chronic pain. Three different cognitive strategies (reinterpretation of pain, attention diversion, and focussing on the pain) were taught to chronic pain patients and the effectiveness of the strategies was evaluated using pain ratings and pain behaviours. Of the three, the strategy that decreased subjective measures of pain, and behavioural observations of pain to the greatest extent, was the reinterpretation of pain strategy. Comprehensive reviews of cognitive coping strategies for pain control are only beginning to appear in the journals: Tan (1982) has compiled a selective review of cognitive and cognitive-behavioural treatment techniques, McCaul and Malott (1984) evaluated distraction methods and Turk, Meichenbaum and Genest (1983) reviewed the cognitive control literature. Turner and Chapman (1982), in their review of psychological interventions for chronic pain, critically reviewed and evaluated studies focussing on cognitive-behavioural techniques and operant conditioning methods. They concluded that, although both methods have demonstrated positive treatment outcomes, cognitive-behavioural techniques show the potential to alleviate pain in many more diverse pain syndromes and are more helpful for pain of lesser chronicity. However, these reviews indicate that although some studies have demonstrated significant differences whereby the training of coping skills of various types 12 have successfully increased subjects' tolerance to induced pain, no one taught strategy appears superior or any more adaptive than any other for all types of pain and all types of pain patients (Lazarus, 1986; Tan, 1982; Turk et al., 1983; Wack & Turk, 1984). Spontaneous Coping Strategies Researchers have observed that most people in pain use some form of cognitive strategy in addition to behavioural pain management strategies (e.g., Copp, 1974). An interesting observation that has arisen from studies evaluating coping strategies is that in many cases, subjects will spontaneously use their own strategies to cope with pain, regardless of the experimental manipulation or instruction (Barber & Cooper, 1972; Chaves & Barber, 1974; Kanfer & Goldfoot, 1966; Scott, 1978; Scott & Barber, 1977a, 1977b; Scott & Leonard, 1978; Spanos et al., 1981). Although such a finding opens up new areas for investigation, it also demands the use of caution when interpreting the results of studies that compared highly specific taught strategies (e.g., Scott, 1978), or those that involved a "control" group not taught a strategy and, thus, generally assumed not to be employing any particularly 'effective' form of coping strategy. In conditions where subjects are given theoretically "ineffective" strategies, do the experimenter's directions call forth the effective spontaneous strategies and thus, subjects show an equal degree of pain control? Do control subjects (not taught experimental strategies) think and imagine, using their own spontaneous strategies in various ways similar to subjects taught the specific strategy? Further studies are needed to examine carefully subjects' own spontaneous strategies when exposed to experimentally induced pain. The investigation of spontaneous strategies promises to provide researchers with a rich source of valuable information about effective and ineffective coping with pain. Studies involving both volunteer subjects and pain patients indicate that spontaneous coping strategies can be used effectively by some subjects to cope with pain. Turk et al. (1983) have argued that in 36% of investigations included in their review, cognitive coping skill treatments were often no better than the subject's use of their own spontaneous strategies. In 13 fact, a decrement in pain tolerance ability was noted in cases when a taught strategy interfered with volunteer subjects' own coping styles. Such an interference effect has also been noted by other investigators (Chaves & Barber, 1974; Tan & Poser, 1982). Future investigations into the training of coping skills for clinical pain patients should take heed. Taught strategies (e.g., active coping interventions), may not be the most suitable for subjects whose own preferred means of coping may be more passive and palliative, involving mechanisms such as denial or avoidance (cf. Roskies & Lazarus, 1980). No studies have evaluated subjects' thoughts when they are being taught the strategies. Emphasis in future research should perhaps be on the act of instruction in combination with the subject's own preferred coping strategies, rather than on the presumed effect of the instruction (changes in strategies) which has not been effectively established. Research has also neglected to examine different modalities of instruction (e.g., modeling, persuasion, guidance, etc.) and their possible varying effects on coping outcome for individuals preferring different coping modalities. Although several cognitive and cognitive-behavioural skill treatments have been developed and effectively employed using volunteer subjects, the extension to clinical populations is still a contentious issue of debate (McCaul & Malott, 1984; Tan, 1982). A potential obstacle for implementing taught strategies is that the self-instructional components of taught strategies may sensitize subjects to their pain (Tan & Poser, 1982). Hackett and Horan (1980) found that the self-instructional component of stress inoculation training for pain control was the least effective and most unpopular. A number of studies have failed to obtain unequivocal support for the efficacy of self-instructional training for pain control (Girodo & Wood, 1979; Hackett & Horan, 1980; Worthington, 1978). Future procedures for assembling treatment packages should involve an assessment of the patient's own coping strategies and these should then be built upon and embellished rather than replacing effective spontaneous techniques. 14 Spontaneous Catastrophising Cognitions Much of the clinical pain coping literature focuses on ineffective copers. All people attempt to cope with pain with variable success. Most pain patients referred for psychological treatment are those that are not coping well with their pain as evaluated by themselves or their physician. Pain patients who report symptoms may be monitoring, appraising and reacting emotionally to their symptoms much differently than non-referred patients (Reesor & Craig, 1988). There is a dearth of studies comparing spontaneous strategies used by effective and ineffective copers at particular phases within the coping process. Turk (1979) maintains that such research would aid in identifying the range of factors that influence the adaptive process. Spontaneous cognitive strategies used by ineffctive copers have been labelled catastrophising. Such terminology has its origins in the cognitive literature dealing with affective disorders (e.g., Beck, Rush, Shaw & Emery, 1979). Catastrophising involves cognitive processes wherebj*- people dwell on the worst possible outcome of any situation for which there is a possibility for an unpleasant outcome (Beck & Emery, 1985). Typicall)' people who catastrophise make catastrophic predictions for situations. These predictions are interpretations in the worst possible way, of any sign of weakness etc. within the individual for dealing with the impending situation. Ellis (1962) characterizes catastrophising as a tj^ pe of faulty thinking typical of many anxious patients. Anxious people exaggerate the possible consequences of the outcome and over emphasize the probability for disastrous outcomes. Such cognitions lead to ineffective coping. Spanos, Brown, Jones and Homer (1981) compared thought processes in volunteer subjects classified as effective or ineffective copers. Subjects were asked to write down all their thoughts experienced during a cold pressor task. Inspection of the results revealed that those subjects whose thoughts were categorized as "coping" thoughts (e.g., they imagined events inconsistent with pain, or engaged in positive self-statements) also reported less pain 15 and had a greater tolerance for pain. Conversely, subjects who reported greater pain intensity and had lower tolerances, were those whose thoughts were labelled in the main as "exaggerated" (e.g., thoughts reflecting worry about or an exaggeration of the pain). Spontaneous coping strategies are beginning to be assessed in the clinical population. In a recent investigation, Reesor and Craig (1988) contrasted chronic low back pain patients (CLBP) with medically congruent symptoms and signs (Waddell, Bircher, Finlayson & Main, 1984) with patients with medically incongruent symptoms (essentially comparing effective versus ineffective copers) on a variety of cognitive and behavioural measures referring to both their clinical pain and a trial of induced pain. Medical incongruence was designated when pain reports were deemed exaggerated, disproportionate, and/or anatomically deviant relative to known organic or physical impairment. The spontaneous cognitive coping strategies were assessed using the Coping Strategies Questionnaire developed by Rosenstiel and Keefe (1983) as well as an interview format adapted from Genest and Turk (1981). Results revealed that strategies tapped by the interview discriminated between groups better than strategies endorsed on the Coping Strategy Questionnaire. "Inappropriate" pain patients' thought processes were found to be significantly more "catastrophic" than the medically congruent controls. No significant group differences emerged in terms of number of specific types of strategies reported. The quasi-experimental design utilized by Reesor and Craig (1988) does not allow for the formation of causal explanations yet it seems that the presence of catastrophising thoughts in CLBP patients is associated with ineffective or maladaptive coping. In summary, the results discussed represent a complicated array of findings and two general conclusions. The first conclusion supporting the cognitive model of pain, is that psychological and cognitive factors affect performance in pain situations. Second, no one form of taught coping strategy has proven more effective than any other in helping individuals improve their tolerance. In fact, the coping strategies that subjects bring into the laboratory 16 may prove as effective, or more effective, than coping strategies the investigator provides. Attempts at skills training may interfere with subjects' own preferred and effective coping strategies (Chaves & Barber, 1974). It is also unclear whether subjects adhere to treatment guidelines to employ specific taught strategies (Barber & Cooper, 1972; Scott & Barber, 1977). It is extremely important for future research in this area to use manipulation checks to determine the extent to which subjects use the recommended strategies. Similarly, it is important to know whether untreated subjects spontaneously generate and use strategies that approximate those offered to the treatment subjects. These observations have implications not only for research, but also for health promotion and treatment of medical problems. Anxiety and Self-Efficacy and Their Effect on Pain Two major factors implicated in the psychological regulation of pain are: anxiety and self-efficacy. Many of the psychological techniques for pain reduction involve anxiety reduction. Patients are taught to use a variety of anxiety- and stress-reducing procedures such as relaxation, hypnosis, biofeedback, as well as a variety of cognitive activities (cf. Weisenberg, 1977; 1984). Sternbach (1974) has tied anxiety most to acute pain. Lethem, Slade, Troup and Bentley (1983) and Slade, Troup, Lethem and Bentley (1983) have proposed a model to explain long-term exaggerated responses to pain. They hypothesized that the key theoretical concept involved in this long term process is the concept 'fear of pain' which is akin to anxiety. This concept is an important factor in the exaggerated responses to pain especially when coupled with ineffectual coping strategies such as avoidance. In general, pain and anxiety have been associated with each other. The general conclusion has been that the greater the anxietj^ , the greater the pain (Sternbach, 1968; Weisenberg, 1977) however, the exact nature of the relationship between pain and anxiety is still not fully understood. For example, in studies of hypnosis, Hilgard and Hilgard (1975) reported that anxiety reduction does not imphy reduction in pain perception. It is possible to 17 have a reduction in anxiety occurring simultaneously with a reported increase in pain perception. Other researchers have demonstrated that anxioylitics, such as diazepam, reduced affective discomfort rather than sensory-intensity qualities of the expereince of painful tooth pulp sensations (Gracely, McGrath & Dubner, 1978). Thus, it would appear that knowledge of anxiety level alone is not adequate when attempting to predict pain reaction. Anxiety may function as a predisposing variable which creates a mental set or schema (Beck et al., 1979) or it may have a direct effect on the person's perception of the situation. Kent (1984) looked at ratings of expected dental treatment pain in both high and low anxious dental patients. He reported that high anxious patients rated their expected pain as higher, but reported actually experiencing less pain than the low anxious patients. Anxiety levels have also been associated with poor tolerance to acute pain (Martinez-Urrutia, 1975; Speilberger, Auerbach, Wadsworth, Dunn & Taulbee, 1973). There appears to be little doubt that there is a strong association between pain and anxiety however, it is clear that there are other intervening factors implicated. The principle assumption of Bandura's (1977) cognitive theory is that psychological procedures, whatever their form, affect behavioural change by serving as a means of creating and strengthening expectations of personal efficacy. An efficacy expectation refers to the conviction that one can successfully execute the behaviour required to produce the outcomes. A person's self-efficacy expectations will thus determine persistence and ultimate success in coping with threats. The assessment of efficacy expectations is valuable in the investigation of the role of cognitive processes in behaviour change (Kendall & Korgeski, 1979; Weisenberg, 1987). Perceived self-efficacy has been shown to determine a broad range of personal skills, including persistence in enduring pain (Bandura et al., 1987; Worthington, 1978) and success in controlling headaches (Holroyd et al., 1984). Turk et al., (1983) have suggested that the difference between high and low tolerant individuals does not appear to be the result of the deficiency in number or type of coping skills employed, rather it seems to be related to 18 motivational factors and the individual's expectancies of whether they can effectively use the skills they possess. Bandura et al. (1987) tested subjects' self-efficacy beliefs of ability to withstand and to reduce the pain of a cold pressor task before, during and after the task. He found that subjects trained to use cognitive pain control strategies such as: attention diversion from pain sensations, use of engrossing imagery, dissociation from pain, and self-encouragement had strengthened perceived self-efficacy to withstand and reduce cold pressor pain. Subjects given a placebo described as an analgesic, had enhanced self-efficacy to withstand pain but no pain reducing ability changes, and subjects who received no intervention had no changes in either form of perceived self-efficacy. Regardless of the condition, the stronger the perceived efficacy to withstand pain, the greater subjects' persistance to the cold pressor pain. While other researchers in the area of pain control have begun to use self-efficacy theory to explain some of their findings (e.g., Turk et al., 1983; Worthington, 1978), more direct tests of the applicability of self-efficacy theory to account for changes in pain behaviour are lacking. Belief systems are argued to influence cognitive appraisals and the emotional consequences that arise from the perceived threat (Beck, 1976). Thus, beliefs about pain and the perception of control over pain may determine the nature of coping processes employed (Girodo & Wood, 1977). As Weisenberg (1984) has pointed out, coping strategies are necessary but not sufficient for successful coping. People must believe they have the skills to cope; that they are capable of using coping skills or strategies; and that their attempts to cope will have some effect on pain. Roskies and Lazarus (1980) argue that how a person copes with a stressor, such as pain, depends on that person's cognitive evaluation of the situation. This cognitive evaluative view, referred to as appraisal, is a dynamic process that changes according to the person's perceived anticipated consequence of an event, its importance to his/her well-being, and the perceived resources he/she has available to cope with the threat. 19 An individual's confidence that a particular skill is adequate is not stable but may fluctuate according to the degree of anticipated danger in the situation (Beck & Emery, 1985). In other words, self-efficacy determines whether the person attempts to cope with or avoids exacerbation of their pain. In short, there are recognizable thought processes that tend to be associated with an ineffective or maladaptive coping outcome. Thus, it is not just the presence of coping strategies but type (catastrophising or adaptive) and the belief in their effectiveness and the level of anxiety that will determine coping outcome (e.g., Reesor & Craig, 1988; Spanos et al., 1981). Non-Verbal Expression and Pain Non-verbal expression provides a means other than self-report of communicating emotions and other subjective states (Craig, 1978; Harper, Weins & Matarzarro, 1978). It is also a primary mechanism for eliciting caretaking and sympathetic responses from others (Fordyce, 1976; Sternbach, 1968). In natural and clinical settings, non-verbal expression is an important determinant of observers' judgements of others' distress. For example, Johnson (1977) reported that clinicians assign greater weight to non-verbal expression than to self-report when judging the severity of patient pain. Clinicians also rely heavily on nonverbal painful expression in formulating diagnostic decisions. For example, diagnostic tests for range of motion require the clinician to induce pain deliberately, with nonverbal expression, rather than verbal report, the primary index of pain (Main, 1982). Inclusion of the behavioural component is intuitively appealing since a large part of the pain experience clearlj' involves such observable motor features as immediate withdrawal from the pain stimulus, rubbing the affected area, vocalizing, and facial grimaces. While these behaviours might be appropriate variables to study in clinical samples, they are not readily amenable to study of the laboratory subject who is not free to get up and move to such an extent during the course of an 20 experimentally induced pain stimulus. One set of behaviours easily adaptable for measurement in laboratory settings is facial expression. It is fortunate that the face represents the most salient and richest source of nonverbal informaion available. Ekman and Friesen (1969, 1974) argue that facial expressions are less amenable to conscious distortion than self-reports of subjective states and they regard them to be the primary source of nonverbal affective communication. Although non-verbal expression plays a critical role in pain experience, systematic study of this phenomena has not been plentiful. In 1872 Darwin discussed pain expression in his conceptualisation of facial expression. He emphasized the adaptive evolutionary role of expressive behaviour. Darwin postulated that our facial expressions are habitually exhibited as expressions of psychological states and he believed in the existence of universal components of pain expression that convey meaning to others. Studies using experimental^ induced pain have demonstrated the close relation between intensity of pain and non-verbal indices. For instance, intensitj" of electric shock has been shown to be discriminable on the basis of facial expression and facial muscle movement (Lanzetta & Kleck, 1970; Patrick, Craig & Prkachin, 1986). This suggests that in some cases, unobtrusive measurement of facial expression might provide more accurate information about subjective states, including pain, than verbal indices. Multidimensional Assessment of Pain Progress in measurement has been slow as pain is a complex perceptual experience that can only be indirectly quantified (Chapman et al., 1985). As it is becoming increasingly clear that pain is an experience consisting of sensory, cognitive and affective-motivational dimensions (Craig, 1984; Melzack & Wail, 1983; Turk et al., 1983; Weisenberg, 1987), the often reported incongruence between pain experience and tissue damage highlights the necessity of a multifaceted approach to pain assessment both in analogue and clinical settings. 21 Furthermore, the use of multiple measures in pain research reflects the view that pain is multidimensional. While a full assessment of pain would include the subjective (cognitive and verbal self-report of pain sensitivity), behavioural and physiological aspects of pain, the focus here has been on the former two aspects which emphasize the communicative or expressive facets. Without a doubt, there is a great deal of inherent difficulty associated with measuring the cognitive and affective processes that modify (and are modified by) the sensory input and the overt behavioural aspects of pain. However, some researchers argue that the private and subjective experiences of pain can be inferred from verbal and non-verbal behavioural indicators of discomfort and distress (Fordyce, 1978). The hypothesized relationships between pain tolerance and the components of pain expression will be discussed at the end of this section. Pain Sensitivity Self-Report Traditionally, concern with the measurement of pain has been devoted primarilj' to evaluations of verbal reports (Ekman & Friesen, 1978; Prkachin, Currie & Craig, 1983). For many purposes, self-report has been found to be sensitive, reliable, and discriminating of variations in pathological conditions (Agnew & Mersky, 1976; Craig & Prkachin, 1983; DuBuisson & Melzack, 1976; Hilgard, 1969). Assessment of self-report can be most accurate and informative when the sensory and affective dimensions of pain are measured separately. Information on these individual dimensions could be useful in better specifying the impact of treatment and other psychological variables on the perceived pain intensity (sensation) and the affective dimension of pain (Price, Harkins & Baker, 1987). A technique that fulfills these criteria, and that is convenient to use in the laboratory has been developed by Gracely, McGrath and Dubner (1978a; 1978b; 1979). Two ratio scales of 12 words each measure the sensory and affective (or unpleasantness) dimensions of the pain stimulus. The pain descriptors were originally scaled and validated by subjects using numerical estimation and cross-modality matching (see Appendix B for the scales and their 22 corresponding ratio values). These scales have proven to be reliable and valid in follow up studies by Gracely and in Craig's laboratory and were therefore used in the present study as measures of pain sensitivity. However, there are limitations to verbal report that can not be ignored. Verbal report is vulnerable to the common problems of any subjective response (e.g. experimenter bias, demand characteristics) that influence self-reported pain. Cognitive Assessment of Pain Measurement of cognitive processes accompanying pain is no easy task given their private nature. Self-report measures have commonly been used in the assessment of pain (especially chronic pain) because of the assumption that only the individual has access to these private experiences (Reesor & Craig, 1988). However, various investigators have argued that self-report of overt or covert behaviour is difficult to distinguish from post-hoc rationalizations (Genest & Turk, 1981; Nisbett & Wilson, 1977). Self-report is vulnerable to distortion by situational factors, mood, and perceived environmental contingencies (Kremer, Block & Atkinson, 1983). One problem in assessing cognitions and thought processes is that self-report is dependent upon cognitive processes superordinate to the contents of the experience, i.e., memory, attention, or decision making processes which are not amenable to introspection (Nisbett & Wilson, 1977). According to attribution theory, Nisbett and Wilson (1977) maintain that an "actor" may overlook or mistake the actual cause and may not be more accurate than an "observer" who does not have access to the "actor's" cognitions. When subjects report on cognitive processes, they do so based on a priori implicit, causal theories or judgements about the extent to which a particular stimulus is a plausible cause of a given response. Hence reports of cognitive events as causal explanations or descriptions of thought patterns may be inaccurate for voluntary or involuntary reasons. Accurate reports will occur when influential stimuli are salient and are plausible causes of the responses they produce. A review of the literature evaluating coping strategies highlights the fact that there is no single agreed upon method to assess spontaneous coping strategies. Alder and Lomazzi 23 (1972) used open-ended interviews and asked subjects what they did or thought about to cope with the pain stimulus. Results showed significant positive correlations between pain tolerance and ratings of subjects' use of coping strategies. Spanos, Radtke-Bodorik, Ferguson, and Jones (1979) categorized reports to open-ended questions after repeated cold-water immersions. Incremental pain tolerance was observed with "non-catastrophizers" from the first to the second immersion whereas "catastrophizers" exhibited no evidence of increased tolerance. The magnitude of the increase was related to the number of coping cognitions employed e.g., imagery, distraction, and relaxing self-statements. Further, the investigators found that a number of subjects may have been spontaneously using a number of cognitive strategies, as suggested by their responses to post experimental questioning, but made misleading conclusions regarding their own cognitions and failed to label them as strategies. From this unexpected finding the experimenters cautioned that if only specific, directed questions are asked the prevalence of spontaneous coping strategies will likely be severely under-reported. Such under-reporting of the use of spontaneous coping techniques may be evidence of (a) an inability to verbally describe cognitive or subjective experiences, (b) a lack of metacognitive ability (Meichenbaum, Burland & Gruson, 1979) or, (c) a lack of conscious awareness of the use of specific coping strategies (Nisbett & Wilson, 1977; Turk, 1979). While recognizing the limitations of the direct assessment of covert processes, Genest and Turk (1981) maintain that biases inherent in self-report can be minimized by the use of open-ended questions, minimizing reflection through cueing, random sampling of self-report, and by asking for non-quantitative judgements. The use of a semi-structured interview format provides a rich source of information (Genest & Turk, 1981; Spanos et al., 1979). To improve recall of the experience, and to reduce biases potentially involved in retrospective recall, Genest and Turk (1981) played the subjects a videotape of their pain experience. This technique helps to minimize reflection and provides self-generated cues not influenced by experimenter bias (Meichenbaum et al., 1979). Merluzzi, Glass and Genest (1981) point out 24 that multiple convergent assessment methods may enhance the validity of cognitive assessment methods. Self-report measures of coping activity during pain have been used to assess cognitions related to CLBP patients in a systematic fashion by Rosensteil and Keefe (1983). Factors derived from items endorsed on their Coping Strategy Questionnaire significantly predicted behaviours, emotional adjustment, and pain ratings beyond patient history and other psychometric variables. These findings were recently replicated by Turner and Clancy (1986). However, Reesor and Craig (1988) found a resulting factor structure that was somewhat different from that reported by Rosensteil and Keefe (1983). One possible reason offered by the investigators for the discrepancy is that the subject to variable ratio was 9:1 in Reesor and Craig's sample, while the ratio for the factor structure reported by Rosensteil and Keefe (1983) was 6:1. Therefore, the factor solution reported by Reesor and Craig (1988) may have been somewhat more stable. Breznitz (1986) questions the existence of coping strategies. He argues that if one wishes to talk about coping strategies there are three requirements to fulfill: (1) there must be a demonstration of planning or intention before the behaviour takes place, i.e. premeditation must be present to consider the behavioural response as a "strategy"; (2) the presence of alternative modes of coping beyond the intention as well as in a choice or preference for a particular "strategy" must be shown; and (3) demonstration of consistency or pattern in the individual's behaviour must be evident. In the absence of consistency one might know that something was perhaps planned but be unable to demonstrate that a strategy was carried out unless expressed in certain consistent patterns. To fully demonstrate the existence of a coping strategy requires planning to allow introspective analysis prior to action. Consistent with Nisbett and Wilson's (1977) views, Breznitz (1986) states that when coping strategies are reconstructed after the event from an individual's self-report, there is the likelihood of over-estimating the strategy's presence. After the event one may find patterns and explanations 25 beyond what is warranted by the actual situation. Thus, Breznitz (1986) argues that, ideally, one needs to have access to thoughts and cognitions prior to the act or stressor to prove the presence of a coping strategy. None of the studies of pain coping reviewed have assessed the subjects' cognitions or coping strategies prior to any of the interventions (e.g., skills training, hypnotic suggestion, observer manipulations, etc.). Inferences about cognitive factors and cognitive mediation have been based on the individual's behaviours or post-hoc self reports with little information available about the cognitive processes that the subject came with to the experiment. Non-Verbal Measurement of Pain Recently, researchers have recognized that other communicative modalties for the assessement of pain may be more important. Non-verbal expression provides an alternative source of pain information that would be expected to supplement and complement self-report (Craig & Patrick, 1985) and might be less susceptible to situational demand characteristics than verbal measures (Craig & Prkachin, 1983). Patients who are unable to use language must be assessed by means of nonverbal measures (e.g., the very young) (Craig & Prkachin, 1983). Harper, Weins and Matarazzo (1978) argue that verbal behaviour is more likely to be discounted than non-verbal behaviour when they are inconsistent. One of the most sophisticated developments to date in the measurement of facial expression is the Facial Action Coding System (FACS; Ekman & Friesen, 1976, 1978a,b, 1982). This descriptive measurement system is based on analyses of the visible muscle movements in the face; how each muscle of the face acts individually or in combination with other muscles to create a visible appearance/expression change. FACS identifies 44 'action units' (AUs; discrete movements in the forehead, eye, cheek, nose, mouth, chin and neck regions) mostly based on single muscles, however where two or three muscles appear to move as one unit, they are classed as a single AU. This system was designed to measure all visible 26 facial behaviour and has been shown to be a reliable and valid tool in the differentiation of certain emotions: happiness, fear/surprise, anger, disgust/contempt, sadness (Ekman & Friesen, 1982), and pain (Craig & Prkachin, 1983). FACS allows experimenters to objectively describe any facial expression in terms of the combinations of action units that produce it. The duration and intensity of facial movements is also codable with FACS. The use of slow-motion videotape feedback allows even brief, complex facial expressions to be scored. FACS has proven valuable in the measurement of pain (Craig & Prkachin, 1983). Craig and Patrick (1985) found six A U categories to occur more frequently during exposure to cold-pressor pain than during a baseline experience: 6/7, 10, 12, 25, 26/27; and 43/45 (see Appendix A for list of AU descriptors). A stepwise multiple regression analysis proposed that AUs 26/27, 6/7/, 12, and 5 best predicted subjective distress at the onset of an acute pain experience. In another studj^ , AUs 4, 6, 10 and 45 occurred most frequently during phasic shock (Patrick, Craig & Prkachin, 1986) and when these AUs were entered in a stepwise multiple regression analysis, more than half of the variance in naive judges' ratings of the pain that the videotaped subjects were experiencing was accounted for by these AUs. In summary, the findings of at least these studies illustrate that there are certain AUs highly correlated with the communication of pain. More specifically, results of these two pain studies have shown success in identifying discrete facial expressive behaviours associated with two different nociceptive stimuli with only partial overlap between them. Patrick et al. (1986) maintain that these differences in AU expression may reflect the different qualitative impacts of these noxious stimuli, thus lending added support to the notion of a multidimensional approach to pain assessment (e.g., Harris & Rollman, 1983). Recently FACS has been employed with a clinical pain population (CLBP patients) by Hyde (1986). Analyses of videotapes of the pain patients undergoing a painful phj'sical range of motion examination supported the laborator}' research findings that AUs associated with self-reported pain were AUs 4, 6, 7, 10, 25, and 43. Evidently the use of FACS has the 27 potential to provide a means of empirically comparing results from both clinical and laboratory research; a unique feature not found with other assessment tools. Experimentally Induced Pain Pain induction procedures have advantages and limitations associated with their unique properties. Acute pain is easily produced in the laboratory (Sternbach, 1984) but an important issue to confront when assessing the external validity of laboratory research is the extent to which nociception in the laboratory is analogous to clinical pain in the nature of the sensations produced. Among the available means of safely and ethically inducing experimental pain, the cold pressor test and muscle ischemia, unlike electric shock, share a close similarity to chronic pain in the sensations of deep, aching pain (Clark & Hunt, 1971; Kunckle, 1949; Turk et al., 1983). A number of studies (e.g., Lovallo, 1975; Scott & Barber, 1977; Turk, 1977) have shown that immersion of a limb in circulating ice water produces a continuing deep, aching or crushing pain that seems closer to the quality, duration and urgency of clinical pain than does that induced by man}' of the other procedures. In comparison to other methods of pain induction, cold pressor pain has a relatively slow onset of distress induction, providing time for the impact of mental operations to take place (Wolf and Hard}', 1943). The cold pressor pain is developed by having subjects immerse some part of the body (usually the hand and part of the arm) in ice water maintained at a stead}' temperature (e.g., 2°C). The pain sensations are a function of a cyclic phenomenon of vasodilation-vasoconstriction called the "Lewis effect". During exposure to the cold water, there is an alternating constriction and dilation of the capillaries near the skin surface (Lewis, 1929). This constitutes an experience of pain wherein vasoconstriction is associated with sensations of aching, crushing pain and vasodilation is associated with numbness, local warming, and relief from the pain. The vaso-dilation is experienced by most individuals between 270 and 400 28 seconds (Teichner, 1965). In most studies employing this procedure, a ceiling of 5 minutes has been established, with exposure terminated at that point at which local warming and numbness appear (Turk, et a!., 1983). Turk and his colleagues (Genest, 1978; Genest, Meichenbaum & Turk, 1977; Turk et al.,1983) noted that subjects in a cold pressor task naturally cluster, into two groups according to their tolerance times. These investigators observed a bimodal distribution among their samples with tolerances either less than 100 seconds or approximately 300 seconds (the ceiling imposed by the experimenters). Similar distributions have been observed by Dworkin and Chen (1985). Statement of the Problem The purpose of the research presented here was two-fold: (1) to identify and quantify facial expressive behaviours that distinguish subjects categorized as tolerant or intolerant to cold pressor pain, and (2) to identify cognitive strategies employed by subjects who endure or withdraw from the noxious stimulation. From the perspective of behavioural medicine, nonverbal expressions of pain, including facial expressions, represent an important subset of pain behaviours for both acute and chronic conditions. Facial expressions of different pain types have been identified (Craig & Patrick, 1985; LeResche & Dworkin, 1984; Swalm, 1987), however, the examination of differences in facial expressive behaviours for subjects who are tolerant or intolerant to noxious stimulation has not yet been examined. Through the use of the FACS system, the most prominent patterns of facial pain activity occurring during cold pressor exposure were assessed and tolerance group differences in facial activity examined. This research also attempted to address an issue of cognitive assessment. Experimental work with induced pain has suggested that the presence of cognitions that serve to magnify noxious sensory input or accentuate lack of control are associated with reduced 29 pain tolerance (e.g., Turk et al., .1983). However the results of past studies endorsing this conceptually attractive link between cognitive activity and pain performance may be erroneous and artifactual due to the post performance assessment of cognitions. Subjects who retrospectively reported catastrophising cognitions and had lower tolerances, may have done so as a function of their performance. That is, for these subjects, there may have been a greater availability of negative cognitions after the task or their self-report may have been distorted by perceived environmental contingencies and other situational factors such as their level of anxiety or mood. Such negative images may overshadow any functional strategies or cognitions that the subject came into the situation with and perhaps used, thus increasing the strength of any spurious relationship found between cognitive activity and pain tolerance. This problem has not gone unnoticed by researchers (Breznitz, 1986; Nisbett & Ross, 1980; Nisbett & Wilson, 1977). In the present study, data was collected on cognitions prior to the noxious stimulation and after the task for half of the sample. The other half of the subjects were assessed only after their immersion. This procedure enabled an examination of types of cognitions and coping strategies the subjects had available to them as thej' anticipated the noxious stimulation. Hypotheses In this investigation it was proposed that differences between individuals' tolerance to a nociceptive stimulus would be manifested in cognitive and behavioural processes, alread}' described, that modulate the pain experience. A number of hypotheses were proposed that highlight these processes: 1. Pain related AUs predicted from prior research were 4, 6/7, 10, 12, 14, 25/26/27, and 43/45. These were expected to occur during the cold pressor experience in this study. 2. Because non-verbal behaviour has been described as an indicator of pain experience it is expected that a greater frequency of facial activity indicative of pain would be displayed by subjects with short endurance times. This would suggest an amplification of pain sensation in 30 this group as indicated by expressive facial behaviour. Conversely, tolerant subjects were expected to have lower facial pain activity measures. 3. It was hypothesized that dysfunctional cognitions (obtained from both the CSQ and the SISP) relating to the search, selection, and interpretation of sensory information concerning pain in a negative or catastrophic manner and/or lack of effective cognitive coping activity during pain would characterize subjects who have short endurance times on the cold pressor task. Such subjects were hypothesized to engage in more catastrophizing (pain amplifying or worsening cognitions) and less coping or pain ameliorating cognitions. 4. Prospective accounts emphasizing different cognitive processes would not necessarily be expected to be reliable predictors of actual performance on the cold-pressor task and would not be hypothesized to necessarily correlate highly with cognitions assessed post-performance. 5. It was expected that different verbal descriptions of pain would be apparent for intolerant subjects in comparison to tolerant subjects. It was hypothesized that subjects with shorter endurance times would choose higher subjective estimates of pain intensity and higher affectivety laden 'discomfort' descriptors. 6. Anxiety level was expected to be negatively related to tolerance. That is, subjects high in anxiety prior to the task would be expected to be less tolerant of the nociceptive stimulus than less anxious subjects. Conversely, self-efficacy scores from the self-efficacy questionnaire were hypothesized to be positively related with tolerance group. Both anxiety and self-efficacy were assumed to exert an influence on the pain performance as measured by pain sensitivity and cognitive variables. METHOD Subjects Sixty female undergraduate student volunteers drawn from the departmental subject pool at U.B.C. served as subjects. Their ages ranged from 18 to 21 years with a mean of 18.32 years (SD = 0.65). Female subjects were used because they are more overtly expressive (e.g., Buck, Miller & Caul, 1974; Craig & Patrick, 1985; Schwartz, Brown & Ahern, 1980). Thirty subjects were randomly assigned to both the pre/post or post only cognitive assessment conditions. Subjects were paid $6.00 for their participation in the study. Apparatus and Materials Cold Pressor Test The cold pressor stimulus consisted of a styrofoam cooler painted black to lend authenticity to the apparatus. A Plexiglas barrier divided the tank into one section containing crushed ice and the other containing ice-free water. Contained in the ice compartment was a circulating pump (Rule, 400 gal. per hr.) with a plastic hose feeding into the water compartment. The pump served a dual purpose: (1) it vigorous^ circulated the water through the ice compartment thereby maintaining a fairlj' constant low temperature, and (2) it prevented local warming of the water near the skin surface of the immersed hand. The lid of the cooler was also painted black and a small hole cut through the cover allowed the subject's hand to enter the cold water compartment. A metal flange was attached to the subject's arm at a point just below the elbow joint extending 9 cm down. The distance between the top of the tank and the circulating water was approximately 7 cm. Thus, for each subject, the part of the arm from the fingertips to a point 16 cm below the elbow joint entered the water. The flange was instrumental in providing a precise account of the duration of the exposure to the cold water task. The flange consisted of two L-shaped pieces of metal attached to a velcro strip encircling the subject's arm. When the arm was inserted into the tank, the edges of the flange made contact with a metal strip surrounding the opening in the cover which completed a circuit activating a battery-operated relay device. This device produced an 32 audible click upon insertion and withdrawal of the subject's hand. A microphone attached to the relay device recorded the clicks on the audio channel of the videotape recorder. It was the time interval between clicks which was the measure of the subject's tolerance to the task. The tank rested on the front half of a platform with the opening to the cold water compartment at an accessible height and distance to the seated subject. A container filled with room temperature water was placed on the rear half of the platform. Prior to each session, crushed ice was added to the ice compartment to bring the temperature down to 1°C. The water temperature was checked after each session to ensure no temperature rise greater than 1°C had occurred. Self-report measures Two 12-point rating scales were adapted for use as dependent measures (Gracely et al. 1979, see Appendix B). To the Gracely "Unpleasantness" scale was added a lower rating of "no discomfort". The uppermost descriptor remained "excruciating". The "Sensory" scale included an added lower rating of "no sensation" and its uppermost descriptor remained "extremely intense". Thus the scales consisted of 13 descriptors each. The panel upon which subjects made their "Unpleasantness" and "Sensory" scale ratings consisted of 13 buttons labelled with letters from A to M which correspond to the descriptive adjectives arranged in ascending order from left to right. Letters were used to avoid choices based on numerical rank rather than word meaning. Gracely, McGrath and Dubner (1979) quantified these affective descriptors in the form of a ratio scale, assigning numerical weights to each adjective and provided evidence for its reliability and validity. Because of the psychophysical scaling properties built into these scales, they have been preferred over other types of rating scales for current pain intensity (Chapman et al. 1985). A tape recorded message cued the subjects to make their ratings at 20 second intervals. Responses were relayed to a similar panel in an adjoining room and recorded by the experimenter. Subjects completed a self-efficacy questionnaire (Appendix C) devised to measure perceived self-efficacy to withstand pain before the cold pressor task. In judging their 33 perceived efficacy to tolerate pain, subjects were presented with 20 items representing increasing lengths of cold-pressor stimulation, ranging from 15 sec. to 5 min. On each scale, subjects checked the items they judged that they could perform as of then. For each item so designated, they rated the strength of their perceived self-efficacy on a 100-point scale, ranging in 10-unit intervals from high uncertainty, through intermediate values of certainty, to complete certitude (Bandura et al., 1987). Measures of strength of perceived self-efficacy to cope with pain were derived from dividing the summed magnitude scores by the total number of items. Subjects also were asked to complete the Coping Strategy Questionnaire (Rosenstiel & Keefe, 1983). This Questionnaire consisted of 42 items reflecting six scales of cognitive strategies (e.g., diverting attention, reinterpreting pain sensations, coping self-statements, ignoring pain sensations, praying or hoping, and catastrophising) and one scale of behavioural coping (e.g., increasing activity level). In addition, there were two pain control effectiveness ratings (i.e., control over pain, and ability to decrease pain) (Appendix D and E). To determine the relative frequency that subjects use coping strategies, mean ratings across all 6 items for each subscale and for the two ratings of effectiveness were computed. Subjects also completed the State-Trait Anxiety Inventory (STAI) (Form X- l , State anxiety) (Spielberger, Gorush & Lushene, 1970). Videotape equipment Subjects' facial expressions were recorded by videotape equipment concealed behind a one-way mirror. This equipment included: a Panasonic AG6300 VHS recorder, an RCA JD975WV colour monitor, and an RCA TC2011/N high sensitivity black and white TV camera. An RCA video date/time generator, model TC1440-B, was connected to the video cassette recorder. It provided the videotapes with a digital time display (minutes, seconds, 60^ns of a second) so that they could subsequently be divided into segments for FACS coding. 34 Procedure The entire procedure took sixty minutes to complete. The subject was taken to a laboratory room containing the two tanks of water, a table on which the self-report panel is mounted and a chair facing the partially obscured one-way mirror. The experimenter explained the nature of the experiment as a study of "peoples' reactions and thoughts to cold water immersion." The procedure, expected duration, and the rate of pay was outlined to the subject with the assurances that the immersion would not result in physical harm and that she could withdraw her hand from the bath at any time. The subject was informed-of her right to withdraw from the study without penalty, or to refuse to answer any questions, and confidentiality was assured. A consent form outlining this information was signed (Appendix F). Videotaping was not disclosed until the debriefing at which time subjects were offered the option of destroying the videotape. (Appendix G). This procedure reduced the likelihood that subjects would modulate their facial activity as a result of being observed (Kleck et al., 1976) and has been used successfully in prior studies. The subject was asked to complete the self-efficacy questionnaire, the STAI and the Coping Strategies Questionnaire. All jewelry was removed from the hand to be immersed. The flange was attached to the subject with the explanation that its contact with the metal strip on the lid of the tank activated a timer to measure the duration of her exposure to the cold water. The subject was asked to ensure contact was maintained between these surfaces so as not to disrupt the timing. The subject was given a set of written instructions and the tape recording which began as follows: During the time when your hand is immersed in the cold water you are asked to rate your feelings using each of the two scales that you see on the stand in front of you. The Sensory Scale on the left represents how intense the sensation, or how strong your reaction to the cold water is. The Unpleasantness Scale on the right represents how unpleasant or disturbing the pain is for you. The distinction between these two aspects of pain might be made clearer if you think of listening to a sound, such as a radio. As the volume of the sound increases, I can ask you how loud it sounds or how unpleasant it is to hear. The intensity of pain is like loudness; the unpleasantness of pain depends not 35 only on intensity but also on other factors which may affect you. Please try to judge these two aspects of pain independently. Whenever you hear the instruction "rate", choose a word from the Sensory Scale and push the button on the panel with the corresponding letter from A to M. Next, choose a word from the Unpleasantness Scale and push the button on the panel with the corresponding letter. The distinction made between the sensory and unpleasantness aspects of pain was adapted from Price et al., (1983). The experimenter then said: I will be in the other room during the session. Before I leave I will ask you to place your hand into the room temperature bath keeping your fingers in a loosely curled position and I will also turn on this tape recorder to provide further instruction. The taped instructions will say "Hand out" - take your hand out of the room temperature water. Do not put your hand into the water until the taped instructions say "Hand In". Insert your hand into the cold water tank while maintaining a comfortable sitting position. You must be careful not to move during the time when your hand is in the tank. Following the "Hand In" instruction, the tape will begin requesting ratings from you based on the two scales on the panel every 20 seconds. Initial exposure to the room temperature water ensured comparable experience and exposure for all subjects prior to the cold pressor. The subject was instructed to rate quickly after each and every request. She was informed that the intensity of her discomfort would increase over exposure time to a point at which she would no longer wish to continue. She was urged to keep her hand in the ice water until she could not tolerate it any longer. At that time, she was to raise her hand out of the water and rest it on the lid of the cold pressor tank until the experimenter returned to the testing chamber. To avoid any risk of physical harm, maximum exposure time was limited to five minutes, the length of time between "Hand In" and "Hand Out" instructions. After the subject had withdrawn her hand from the cold water bath, the experimenter returned to the testing room with towels to allow the subject to dry her arm. Cognitive Assessment Subjects were assessed using a structured interview adapted from Genest and Turk's (1981) Structured Interview Schedule for Pain (Appendix I, scoring key: Appendix J). Specific times were used as cues to help them describe what they were 36 thinking, feeling, and experiencing at these moments during the exposure: (a) before immersing their hand in the cold water bath; (b) just after they had immersed their hand; (c) after they felt and reported pain; (d) while they gave ratings from time to time; and (e) just before they withdrew their hand. The reports were tape recorded and transcribed verbatim. Subjects in the pretest/posttest group were interviewed regarding their cognitions immediately prior to and following the water immersion. The posttest-only subjects were interviewed immediately following their immersion. The only difference between the interviews at the pre-test and post-test was that the tense of the cues used for the interview was altered to suit the testing time. Genest (1978) used a videotaped record of the subject's own pain experience to aid in recall of the pain experience. However, Reesor (1986) indicated that in pilot testing of the interview, recalling the sequence of events (a to f above) was sufficient to elicit descriptions of cognitive activity. After the immersion and the interview, the subject completed the post test questionnaire (Appendix H) and then was debriefed as to the true nature of the study, our interest in videotapes, and the reason for the deception. No subjects opted to have their videotapes erased and no subjects dropped out of the study for any reason. Coding Five 3-second segments from each subject's videotape were selected for scoring. The first of these was a "baseline" segment taken while the subject had her hand immersed in the room temperature water. The 3-second "baseline" corresponded to the first 3 consecutive seconds of the 30-second baseline record that were scorable (i.e., where the subject's face was wholly visible for scoring). This segment was selected to provide a record of spontaneous facial expression which could be compared with facial behaviour during exposure to the noxious stimulation. Segment 2 corresponded to the first 3 seconds of cold pressor exposure for each subject, that is, the facial activity in the 3 second period immediately following immersion of the hand 37 in the ice cold water. This segment was chosen to compare subjects' initial reactions with their behaviour at later points. Segment 3 provided a record of the subject's facial behaviour during the 27 to 30 second mark of cold pressor exposure. Since all subjects retained for analysis withstood the cold pressor test for at least 33 seconds, Segment 3 was available for the entire sample. This allowed a comparison of facial behaviour of subjects in the different conditions after a comparable period of reasonably substantial exposure to the cold pressor test. Segment 4 corresponded to the 3-second period immediately preceding the first rating higher than 'Very Unpleasant' (G) on the 'Discomfort' scale. This rating level was chosen because it is beyond rating 'G' that the self-report descriptors denote "pain" as opposed to discomfort or unpleasantness. Thus, the expressive behaviour of subjects could be compared at the same level of self reported discomfort. In short, segment 4 was chosen to provide a sample of subject facial behaviour during early reports of experiences akin to the pain threshold. Segment 5 corresponded to the last 3 seconds of cold pressor exposure for each subject; that is, facial expressive behaviour occurring in the 3-second period immediately preceding withdrawal of the hand from the ice cold water bath. This segment was selected to permit group comparisons of facial expressiveness at the point where subjects terminated (either of their own volition or by the experimental ceiling) their cold pressor exposure. These five segments were located by the experimenter on the subject's videotape and their positions specified via the time display provided by the time-date generator. A data coder who has passed proficiency tests as a FACS coder scored the facial expression (Ekman & Friesen, 1978a). Each segment of videotape was scored for all 44 facial action units (AU's) specified in the FACS system. 38 This procedure has been used before and resulted in inter-rater reliabilities of 0.85 for agreement of the occurrence of pain-related AUs, 0.71 for agreement of all AUs scored (Craig & Patrick, 1985) and 0.76 for percentage agreement (Hyde, 1986). Patrick et al. (1986) calculated two intercoder reliabilities: (1) the ratio of total number of agreements to total number of AUs scored was 0.74, and (2) the ratio for 13 pain related AUs was 0.84. Two undergraduate students were used as coders for the Structured Pain Interview. They were given a manual and trained to criterion level before coding the subjects' reports. 39 RESULTS Overview of the Statistical Analyses Dependent variables were divided into three a priori conceptual groups: behavioural, subjective pain sensitivity self-report and cognitive variables. Each set of variables was analyzed first using MANOVA's and then, where warranted by significant multivariate effects, univariate analyses were conducted on variables within each of the three sets. Data from the State Anxiety Inventory (STAI) and the Self-efficacy questionnaire were analyzed in a oneway between subjects factor MANOVA to determine if that combination of variables could account for differences between the two pain tolerance groups (tolerant, intolerant). Univariate analyses were then examined to identify the covariates to be used in subsequent analyses. The purpose of these analyses was to identify variables that might potentially confound the interpretation of differences between groups on the dependent variables. The variable identified as a potentially confounding variable was included as a covariate in MANCOVA's for each of the three sets of variables. Univariate analyses of covariance were examined when appropriate. Comparison of the analyses first with and then without the introduction of the covariates was used to clarify the interpretation of the results. Finally, in order to assess the relative contribution of variables in discriminating intolerant from tolerant cold pressor pain subjects, all the significant dependent variables from the univariate analyses involving the covariate were entered into a step-wise discriminant function analysis. The purpose of this analysis was to determine the variables that significantly discriminate intolerant from tolerant subjects. 40 Group Differences: Subject Characteristics The first step of the analyses was to examine the distribution of tolerance times to the cold pressor test to confirm past observations (e.g., Dworkin and Chen, 1985; Turk et al., 1983) that the,distribution of tolerance times to the cold pressor test clusters into two distinct groups. Figure 1 illustrates the distribution of subjects' tolerances in this sample. The median of the population (N = 60) lay at 175 seconds (maximum permissible tolerance time was 300 seconds). The intolerant group ranged from 33 to 175 seconds endurance while the tolerant group ranged from 239 to 300 seconds in the cold water. The scores from the STAI and the self-efficacy questionnaire were entered into a oneway MANOVA to determine if these variables distinguished between the tolerance groups. The overall F was significant (F(2,57) = 5.899,_rj<.005). Inspection of the univariate F's revealed significant effects for only the self-efficacy questionnaire. Tolerant subjects had higher scores of perceived self-efficacy regarding the task than intolerant subjects. Self-efficacy scores were included as covariates in the subsequent analyses. The means and results of the univariate analyses performed on each of the dependent variables have been listed in Table 1. Figure 1 Cold Pressor Tolerance Distribution 28 49 70 91 11 2 1 33 1 54 1 75 I 96 21 7 238 259 280 300 Tolerance Time (seconds.) 42 Table 1 Group Differences of Self-efficacy and Anxiety Scores: Means and Univariate Analyses Tolerance Group Source: Group effect Intolerant Tolerant Variable M £D_ M S_D_ fi1,58) p. Anxiety (a) 36.70 7.37 . 34.20 7.09 1.84 0.18 Self-efficacy (b) 17.28 10.74 31.24 20.75 10.72 0.002* n=30 per group; *p_ < 0.005 (a) higher scores reflect higher anxiety (b) higher scores reflect higher perceived self-efficacy 43 Behavioural Analyses: Facial Expression Indices Facial expression indices of the tolerant and intolerant subjects were examined to determine if there were any apparent group differences. Reducing the Number of Dependent Variables As discussed, each of the five videotape segments selected for analysis was coded for all 44 AU's specified by the FACS system. To eliminate consideration of rarely occurring AU's, the top 25% of all AU's for all subjects were retained for subsequent analyses. Of the 44 scorable actions specified by the FACS system, the following 9 AU's in descending order of frequency remained: 45, 25, 12, 04, 26, 14, 23, 41, and 10. Preliminary Analyses: Baseline versus Cold-Pressor Exposure A repeated measures MANOVA was carried out to determine which of the 9 dependent measures of facial expression were more evident during exposure to the noxious stimulus. The overall multivariate test was significant, jj\9,51) = 4.37,ja<.0001. Univariate analyses at the .05'level revealed significant differences on 6 of the 9 dependent measures. Results of the univariate analyses appear in Table 2. The 6 AU's significantly different between the baseline (3 second segment before the task) and the cold pressor segments (mean of videotape segments 2,3,4,5) were retained for subsequent analyses. A U 45 was the most frequent category, occurring an average of 0.66 times per subject during each of the cold pressor segments. All but 5 subjects showed at least one occurrence of AU 45 during the cold pressor exposure. However, the frequency per segment varied greatly from subject to subject: from 0 occurrences over all four segments during the cold pressor exposure to 8 occurrences in the 4 segments. The other AU categories were not displayed universally. AUs 4 and 10 were totally absent during baseline and were observed among only 8 and 7 of the subjects respectively, with frequencies of occurrence ranging from 0 to 3. AU 12 was displayed at least once by 25 subjects, ranging from 0 to 4 occurrences; AU 14 by 10 44 Table 2 Action Unit (AU) Categories Remaining After Application of Exclusion Criteria: Mean Frequency of Occurrence for Cold Pressor and Baseline Periods and Univariate Analyses Frequency Data Baseline Cold Pressor Source: Seament effect AU Descriptor . M n £D_ F( 1,59) e. 4* brow lowerer 0 0 0.06 0.18 7.08 0.01** 10* upper lip raise 0 0 0.04 0.10 8.25 0.006** 12* lip corner pull 0.10 0.30 0.19 0.27 4.86 0.031** 14* dimpler 0 0 0.05 0.12 10.41 0.002** 23* lip tight 0.05 0.22 0.03 0.11 0.44 0.51 25* lips part 0.18 0.39 0.38 0.45 13.36 0.001** 26* jaw drop 0.03 0.18 0.05 0.11 0.24 0.626 41 lid droop 0.08 0.33 0.02 0.06 2.25 0.139 45* blink 0.95 0.99 0.66 0.45 5.75 0.02** * consistent with Craig and Patrick (1984), and/or Hyde (1986), and/or Patrick et al. (1986) and/or Swalm (1987) findings. * * p_<.05 (retained for further analyses) Note: Baseline period = videotape segment 1, Cold pressor period = mean of videotape segments 2, 3,4, and 5; n=60 subjects per period. 45 subjects, 0 to 2 occurrences during the cold pressor, and AU 25 was displayed by 34 out of the 60 subjects, ranging from 0 to 7 occurences. Derivation of Facial Activity Score . To establish a quantitative index of the facial response to the cold pressor exposure, a principle components analysis (PCA) was performed on the correlation matrix of frequently occurring AU's previously derived. Schaffer (1978) reported that the PCA is the method of choice when data includes multiple occasions of measurement as it permits a more precise specification of the effects of treatment over time. He also argues that it is possible that this procedure increases the sensitivity of further statistical analyses. For the purposes of this study, the PCA permitted analyses of a composite score for facial activity in contrast to analyses that focus on the separate, equally weighted 6 AU's. PCA extracted the major component that accounted for the largest amount of variance. The principle component is the most internally consistent and reliable linear combination of the variables. In this study, the eigenvalue for the extracted principle component was 1.816. The factor score coefficients for the first principle component derived from this solution were used to weight the 6 frequently occurring AU's for individual subjects. These weights are listed in Table 3. A weighted sum of the 6 AU's formed the measure of facial pain activity for each subject. This procedure was done for each videotape segment thus, each subject had an index of facial pain activity formed by the clustering of the weighted AUs at each of the 4 cold pressor segments. Table 3 Weights Used To Derive The Facial Pain Activity Measure AU Descriptor Weight 12 lip corner pull .7333 25 jaw drop .6692 04 brow lowerer .6177 10 upper lip raise .3973 14 dimpler .3356 45 blink -.4228 47 Group Comparisons: Facial Expressivity Group comparisons of facial activity during cold pressor pain segments were conducted using two approaches. The first set of analyses used the facial pain activity measure derived for each subject at each segment. A second set of anatyses examined the individual equally weighted 6 AU's that were found to be significantly more frequent in the cold pressor segment (AU's: 4, 10, 12, 14, 25, 45). Facial Pain Activity Measure In the first analysis, a repeated measures ANOVAR was performed using the four facial pain activity indices at each segment (i.e. cold pressor segments 2, 3, 4, and 5). The between groups factor was the tolerance level divided into tolerant and intolerant groups based on the population median (see Figure 1). No significant effects were obtained from this analysis >0.1). The summary of the ANOVAR results are presented in Appendix K. Thus, facial expressions of both tolerant and intolerant subjects were similar across all segments of the cold pressor experience. Individual Facial Action Units For the second approach, the individual AU's at each segment were used in a 2 X 4 (tolerance group X segment) repeated measures MANOVA. The only significant main effect was the segment effect,_F(18,41) = 3.91, _g<.0001). The group effect and the interaction between the two main effects were non-significant (Appendix L). Univariate analyses were carried out to examine which dependent variables were significantly different between segments, results of these analyses and means for the dependent variables are shown in Table 4. Multiple comparisons using the Tukey range tests were conducted for the Segment effect for the dependent variable AU 45 (blink). Significant effects were found for this action unit between segment 5 and 4 and segment 5 and 3 _(n< .05) (Figure 2). Thus, tolerant and intolerant subjects did not differ with respect to the mean frequency of individual facial action units displayed during each segment of the cold pressor task. However, A U 45 (blink) varied greatly in frequency over the different videotape 48 Table 4 Comparisons of Facial Action Units (AUs) Between Segments: Means and Univariate Analyses Segment Source: Segment effect AU Descriptor 2 3 4 5 F(3,174) SL 4 brow lowerer M 0.05 0.05 0.05 0.10 0.55 0.65 SD. 0.22 0.29 0.29 0.35 10 upper lip raise 0 0.05 0.02 0.08 1.82 0.15 SD. 0 0.22 0.13 0.33 12 lip corner pull M 0.13 0.17 0.20 0.27 1.59 0.19 SJ2 0.39 0.38 0.40 0.48 14 dimpler Jl 0.67 0.08 0.02 0.03 1.25 0.29 SD_ 0.25 0.28 0.13 0.18 25 lips part a. 0.33 0.33 0.38 0.48 1.51 0.21 SD_ 0.51 0.51 0.61 0.73 45 blink n 0.68 0.57 0.42 0.97 6.19 0.001* SD_ 0.79 0.83 0.62 0.82 * p_<.001 49 Figure 2 Distribution of AU 45 (blink) over Cold Pressor Videotape Segments Mean Frequency of Occurrence 2 3 4 5 Segment 50 segments. Regardless of tolerance capbilities, subjects blinked more frequently just prior to termination of their cold pressor experience (whether this was a self-imposed or experimenter directed termination) than at more 'intermediate' points during their exposure. Self-Report Measures of Pain Sensitivity Self-report measures of pain sensitivity were examined in an attempt to discern pain tolerance group differences among such measures. Group Differences: Self-Report Measures of Pain Sensitivity . A onewaj' MANOVA was carried out to examine group differences on 9 measures of sensitivity to the noxious stimulus used in this study. Three of these dependent measures related to subjects' ratings of sensation during the cold pressor test. The three measures were chosen to correspond approximately with the videotape segments 2, 3, and 5 chosen for FACS analysis: magnitude of initial rating of sensation (cf. segment 2: initial 3 seconds of scorable facial activity during the exposure), magnitude of the third rating (cf. segment 3: 27 to 30th second of exposure), and magnitude of final rating before terminating the exposure (cf. segment 5: 3 second period immediately preceding hand withdrawal). Again, subject ratings were assigned their appropriate numerical weights (Gracely, McGrath & Dubner, 1979) for purposes of analysis. Three more dependent measures related to subjects' ratings of unpleasantness during the cold pressor task. These measures were chosen in the identical manner as above. A seventh 'rating' dependent measure was chosen to correspond with the videotape segment 4. This measure was the number of ratings made before selecting a rating of 'very unpleasant' or higher on the unpleasantness scale. The final two dependent measures were items 2 and, 8 of the post-test questionnaire (Appendix H). The former asked subjects to rate the pain of the cold pressor test on a 7-point 51 scale, the latter to estimate their time of exposure to the noxious stimulus. Subjects' estimated time of exposure was converted to a discrepancy proportion: Estimated time of exposure - Actual time of exposure Actual time of exposure This was done to correct for the greater margin of estimate error associated with longer exposure times. The overall multivariate test was significant (F(9,50) = 2.723,_p_<.05). Prior to the introduction of the covariate, univariate F's for the dependent variables were conducted and significant results were obtained for: the post test pain rating, the final ratings of both sensation and unpleasantness and the number of ratings made before choosing a descriptor higher than ver}' unpleasant. After controlling for the possible effects of differing strengths of self-efficacy to withstand pain, the multivariate test again reached significance (F(9,49) = 2.41, _p_<.05) however, only the discrepancy score of estimated exposure time to the cold pressor and the final rating of sensation reached significance. Table 5 presents means and F-ratios of the univariate analyses. 52 Table 5 Group Comparisons of Pain Sensitivity Self-Report Indices: Means and Univariate Analyses Group Analyses: Group effect Intolerant Tolerant Without Covariate With Covariate Variable Obs. Ad). Obs. Adj. £(1,58) p_ £(1,57) p_ Tolerance M -0.32 -0.28 -0.48 -0.53 2.23 0.14 5.09 0.03* discrepancy score (a) Post test rating M 5.37 5.32 4.83 4.88 4.05 0.049* 2.36 0.13 of pain severity (max=6) Initial sensation M_ 16.46 15.14 21.93 23.25 1.25 0.27 2.35 0.13 rating (max=59.5) 30 second sensation M_ 28.32 27.63 22.14 22.84 2.06 0.16 1.04 0.31 rating (max=59.5) Final sensation M 52.15 50.77 40.19 41.56 7.93 0.007* 4.06 0.049* rating (max=59.5)-lnitial(max=44.8) ft 10.23 9.50 9.16 9.87 0.20 0.66 0.02 0.88 unpleasantness rating 30 second M. 17.15 16.36 12.53 13.32 2.87 0.96 1.07 0.31 unpleasantness rating Final (max=44.8) M_ 35.68 34.58 27.41 28.51 5.95 0.02* 2.76 0.10 unpleasantness rating No. of ratings below M 1.93 2.12 3.43 3.25 4.78 0.03* 2.34 0.13 7th descriptor (max= 15) * C < .05; n=30 per tolerance group (a) estimated exposure time = discrepancy score = estimated time - actual time actual time Note: Obs. Observed means before covariate analysis Adj. Adjusted means after the covariate analysis Self-efficacy questionnaire scores used as covariates. 53 Cognitive Measures Self-report measures of cognitive strategies taken from a retrospective and an in-vivo assessment standpoint were assessed to determine if they distinguished between tolerance groups. Structured Interview Schedule for Pain A reliability check was performed to determine how well the trained undergraduate coders concurred in their ratings of the structured interviews. The reliability index was the ratio of agreements over the total number of sentences coded. The magnitude of this ratio for a random selection of four practice interviews was calculated to be 0.87, a respectable level of intercoder agreement. The interviews in each condition (pre/post) were coded on three dimensions: (1) the frequency of each category of cognition in the interview, (2) the proportion of the total interview that category occupied, i.e., frequency of occurrence divided by the total number of sentences in the interview, and (3) qualitative ratings of each interview for each category as outlined in the scoring key (Appendix J). Due to the infrequent self-report occurrence of all of the cognitive categories for each subject, the mean of the four cognitive strategies relating to coping (e.g., dissociation from pain, relaxation, use of imagery, and non-imagery distraction, for examples see Appendix J) was calculated on each of the three dimensions (frequency, proportion, and qualitative ratings) for each subject's interview(s) (pre and post test interviews where applicable). Pearson correlations were conducted for each cognitive designation (i.e., coping, sense of control, catastrophising) examining the relationships among each of the three measures of that designation. Correlations are presented in Table 6. As the relations among the three measures of each cognitive strategy category were reasonably high and uniform and significant (p<.0001, one-tailed), a PCA was conducted for each strategy designation. Only the principle component was extracted to provide an 54 Table 6 Correlations Among the Three Measures of Each Cognitive Strategy of the Structured Interview Schedule for Pain Cognitive Strategy : Coping Sense of Control Catastrophising Variable Pair Pre Post Pre Post Pre Post Frequency with Proportion 0.71 0.60 0.84 0.78 0.60 0.70 Frequency with Qualitative 0.88 0.89 0.80 0.83 0.56 0.78 Proportion with Qualitative 0.79 0.62 0.86 0.85 0.76 0.88 C. < .0001 for all correlations, one tailed n=30 for Pre groups, n=60 for Post groups 55 internally consistent and reliable index of each cognitive designation for both the pre and post interviews. Thus, each subject received three scores for their interview: a coping strategy designation (pre/post)^ , a sense of control designation (pre/post) and a catastrophising score (pre/post). Group Differences: Pre and Post Structured Interview Scores The relationship between the pre-cold pressor interview measures and post-task interview measures were assessed (Table 7). All the correlations were significant (j)<.05, one-tailed) for the relationships between the pre and post measures of the interview. Thus, measures of cognitive strategies from the in-vivo structured interview for pain taken at pre-test, consistent^ predict cognitive strategies assessed from the self-report post-task interview. A .one-way repeated measures MANOVA was used to examine group differences on the pre and post interview scores using the three categories of cognitions derived from the PCA analysis of the three measurements of each category in the interview, and the number of sentences in each interview. There were no significant main effects for either the presentation time of the interview (i.e. pre versus post), nor for the pain tolerance between group factor _(£>.05) but a significant interaction effect between tolerance group and time of interview presentation (F(4,25) = 3.99,_£<.05) was observed. A MANOVA summary table is shown in Appendix M. Univariate F's for each of the variables in the interaction were examined to determine which variables were significantly different between groups. Means and univariate results are presented in Table 8. The number of sentences of the interviews was significant in this analysis and a simple main effects analysis was carried out at each time period (pre/post)(Figure 3). A significant effect was observed for the difference in number of sentences of each interview at the post-test only between the tolerance groups (F(l,56) = 12.11,_rj <.001). High tolerant subjects tended to verbalize more at the post-test Table 7 Correlations Among Pre and Post Cognitive Strategy Measurement Cluster Scores of the SISP Variable (pre vs. post) Correlation coefficient p. Coping strategy 0.40 0.01* Catastrophlsing 0.45 0.007* Sense of Control 0.31 0.048* *p_<.05, one-tailed; a=30 57 Table 8 Pre and Post Structured Interview Cognitive Strategy Measurement Scores: Means and Univariate Analyses Tolerance Group Intolerant Tolerant Source: Group X Time effect Variable pre post pre post F( 1,28) a Coping Strategy -0.28 -0.36 0.24 0.30 0.11 0.75 sp_ 0.99 0.98 0.97 1.10 Sense of Control M -0.29 -0.16 0.26 0.32 1.68 0.21 SP_ 0.75 0.92 1.14 1.11 Catastrophising Jl 0.38 0.02 -0.33 -0.19 0.04 0.85 0.99 1.08 0.91 0.98 Number of sentences M 13.64 13.57 18.50 25.63 8.83 0.006* in theinterview 4.25 5.52 10.38 13.59 * p_ < .01; n= 15 per tolerance group Note: Higher values for each category reflect greater activity of that cognitive strategy. Figure 3 6roup Differences in the Number of Sentences in Pre and Post Structured Interviews Mean Number of Sentences 30 25 f 20 15 10 5 • o-Pre Post Time of Assessment Low tolerance High tolerance 59 than intolerant subjects. The difference in number of sentences for either group at the pretest was not significant. Coping Strategy Questionnaire Scales Prior to analyses of group differences, the nine CSQ scales were collapsed into three a priori cognitive strategy categories: the active use of coping strategy to deal with pain, a pain related sense of control or self-efficacy, and catastrophising and a perceived need for a miraculous intervention. This was done to reduce redundancy among the scales. These a priori categories were similar to the factor structure reported by Reesor (1986). They were also conceptually similar to the three main cognitive strategy designations coded in the SISP. Specific pain coping strategies forming the coping score on the CSQ were also reflected in the coping strategy designation of the SISP. Similarly, self-efficacy or control ratings on the CSQ closely resembled cognitions recorded in the sense of control designation of the SISP. Catastrophising and perceived need for miraculous intervention from the CSQ also closely resembled the coding criteria of the SISP for catastrophising. However, as Table 9 indicates, the correlations among these cognitive variables were nonsignificant with the exception of coping. Group Differences: Cognitive Measures (CSQ and SISP) A total of six cognitive measures (the three Coping Strategy Questionnaire scores and the three in-vivo interview cluster measures of coded cognitive categories in the post interviews) were analyzed in a one-way tolerance group MANOVA. Since an association between self-efficacy and pain tolerance group was found, variables were analyzed first without the self-efficacy questionnaire scores and then with self-efficacy indicators included as covariates. There was a significant multivariate main effect for tolerance group both with (F(6,53) = 3.31,_£<.05) and without (F(6,52) = 2.74,j)<.05) self-efficacy questionnaire scores taken into consideration. 60 Univariate F's for the individual variables were examined to determine which variables were significantly different between groups when the strength of the self-efficacy belief was controlled for. Means and univariate results are presented in Table 10. Relative to intolerant subjects, tolerant subjects reported on the post-test in-vivo measure that coping was characteristic of their thinking when they felt pain even when self-efficacy was covaried out. In comparison to tolerant subjects, intolerant subjects reported more catastrophising cognitions and thoughts of praying or hoping for a miraculous intervention. This difference was not significant when self-efficacy beliefs were covaried out. 61 Table 9 Relationships Between Coping Strategy Questionnaire Scores and Structured.interview Cognitive Categories Measurement Scores Coping Strategy Questionnaire Scores Structured Interview Active Coping Pain Self- Catastrophising/ Schedule for Pain Scores Strategy Efficacy' Praying-Hop ing Coping Strategy (pre) 0.09 0.001 0.09 (post) 0.23* 0.27* -0.17 Sense of Control (pre) 0.42* 0.24 -0.07 (post) 0.14 0.21 0.13 Catastrophising (pre) -0.15 -0.25 -0.14 (post) -0.12 -0.10 0.19 * p_< .05, one-tailed; n=30 for pre group; n=60 for post group Table 10 Group Differences Between Coping Strategy Questionnaire and Structured Interview Categories: Means and Univariate Analyses Group Analyses: Grouo effect Intolerant Tolerant Without Covariate With Covariate Obs. Adj. Obs. Adj. £(1,58) a £(1,57) p_ Variable Copino Strategy Questionnaire Coping Strategy 2.90 2.98 3.18 Self-Efficacy 3.47 3.51 3.60 Catastrophising 2.53 2.49 2.38 Structured Interview Schedule for Pain (post) Coping Strategy -.42 -.42 0.43 Sense of Control -.23 -.20 0.23 Catastrophising 0.26 0.19 -.25 3.12 2.39 0.13 0.50 0.48 3.55 0.54 0.47 0.04 0.84 2.41 0.42 0.52 0.10 0.75 0.42 12.98 0.001* 10.69 0.002 0.20 3.34 0.73 2.14 0.15 -.19 4.00 0.50* 1.99 0.16 *P_<.05;N=60 Note: Self-Efficacy Questionnaire scores used.as covariate. 63 Discriminant Function Analyses of Pain Tolerance Group Since the tolerance groups were comprised of equal numbers of subjects, behavioural, self-report, and cognitive measures were included in a discriminant function analysis to determine what dependent variables optimally discriminated the two types of tolerance times to cold-pressor pain. The four dependent variables that were significant in the previous covariate analyses in distinguishing between tolerance groups and self-efficacy questionnaire scores were entered into the equation. These variables included the number of sentances in the post-test interview, the pain tolerance discrepancy score, the final rating of sensation and the post-test in-vivo interview cluster score for presence of coping strategies. In the first analysis, all the variables were entered simultaneously resulting in a significant discriminant function (X (5) = 30.84,_£< .00001) in which 80% of subjects were correctly classified as to pain presentation (Table 11). Following this analysis, a stepwise discriminant function analysis was conducted to determine what set of variables optimally discriminated the two tolerance groups. Since the use of stepwise entry order as a criterion for determining the relative importance of variables has been questioned (Huberty, 1984), standardized weight of the first discriminant function and the F-to-remove index were used in determining the relative importance of variables. The values have been presented in Table 12. As this table shows, all the variables except the coping strategy cluster score from the structured interview emerged as optimally discriminating the pain tolerance groups. The determinant function based on these variables correct]}' classified 82% of the subjects. Three intolerant subjects were misclassified as Tolerant, while 8 Tolerant subjects were misclassified as Intolerant. Table 11 Classification of Pain Tolerance Membership with the Discriminant Function Predicted Group Actual Group Intolerant Tolerant Intolerant 26 4 Tolerant 8 22 Table 12 Relative Ordering of Discriminating Variables Statistic Standardized Discriminant F to Variable Function Coefficient Remove Total number of sentences (post interview) 0.71 13.10 Self-efficacy questionnaire scores 0.57 7.63 Final rating of sensation - 0.40 3.78 Tolerance discrepancy score - 0.32 2.24 65 Relationships Among Cognitive Variables and Facial Expression A correlation matrix was constructed to investigate the relationships among the amount of facial activity during the cold pressor exposure and the eleven cognitive variables from the Coping Strategy Questionnaire and both the pre and post-test of the Structured Interview Schedule for Pain cognitive cluster scores (Table 13). Only two variables, the coping cluster score from the post-test of the structured interview and the mean number of sentences for the post-test interview correlated significantly with a measure of facial activity computed for the entire cold pressor exposure. Table 13 Correlations Among Cognitive Variables and the Facial Pain Activity Measurement Score Variable r Cooina Strategy Questionnaire Cognitive Categories (N=60) Coping -0.188 0.15 Catastrophising. 0.047 0.72 Self-efficacy -0.163 0.21 Structured 1 nterview Schedule for Pain (Pre-test, N=30) Coping 0.97 0.61 Catastrophising -0.122 0.52 Sense of Control -0.061 0.75 Number of Sentences in Interview -0.293 0.17 (Post-test, N=60) Coping -0.292 0.02* Catastrophising 0.177 0.18 Sense of Control -0.173 0.19 Number of Sentences in Interview -0.298 0.02* *G< .05, two-tailed test 67 DISCUSSION Past research has noted the lack of correspondence among the multi-dimensional aspects of pain. This investigation was designed to permit an evaluation of which self-report, cognitive and facial activity variables differentiate between people with a high tolerance to induced pain and those with a shorter endurance. Consistent with past observations, findings from this research established that subjects did cluster into two endurance groups during cold pressor stimulation (Dworkin, personal communication; Turk et al., 1983). The results of this study indicated that differences in.the tolerance group designation were consistent with differences in self-report of pain sensitivity and the presence/absence of coping and catastrophising cognitions. Measures of facial activity failed to distinguish between the two tolerance groups. The findings for the self-report, cognitive and facial indices of the cold pressor pain experience are discussed separate^, followed by a summary of the cognitive assessment issues relevant in this study. The final section presents a summary of the findings and an analysis of implications for future research. Self-Report Measures of Pain The present study found that tolerant subjects differed from less tolerant subjects in their self-report of pain sensitivity. The variables that were significantly different between the groups were the final ratings of sensory intensity and affective discomfort, the number of ratings made before rating the experience as very unpleasant or higher, and the post-task subjective rating of amount of pain experienced. The results supported the hypothesis that tolerant subjects would have significantly lower ratings of sensation and discomfort during their cold pressor experience than less tolerant subjects. However, this difference was apparent only at the final ratings of each of 68 these two dimensions. Tolerant subjects also took comparatively longer to make a rating exceeding "very unpleasant" on the Unpleasantness Scale. Thus, it would appear that subjects persisting in the cold pressor task did not perceive it to be as intense a sensation and were not as distressed by the noxious stimulation, especially moments before the experiment was terminated, than subjects who withdrew relatively quickly. Tolerant subjects also retrospectively rated their overall experience as less painful. Thus, in comparison to less tolerant subjects, the subjective pain experience tended to be perceived and judged as less disturbing and distressing for tolerant subjects, even from a retrospective standpoint. While the emphasis here was on whether differences in the dependent measures were associated with the apparent differences in pain tolerance for this study, the role of the strength of self-efficacy beliefs to withstand cold pressor stimulation was also important. Relative to other variables that differed between the two tolerance groups, the presence of thoughts indicative of personal self-efficacy beliefs to withstand the cold pressor pain were one of the most important discriminators of the tolerance designation. The strength of the self-efficacy beliefs to endure the cold pressor pain were greater in the pain tolerant group. Bandura and his colleagues (1986, 1987) have pointed out that greater pain persistence is associated with stronger beliefs of self-efficacy to withstand pain. Since subjects came to the , experiment with varying strengths of their personal self-efficacy to tolerate the induced pain, this variable was used as a covariate in the analyses. Group differences, such as the final rating of unpleasantness of the stimulus, the retrospective pain rating from the post-test questionnaire, and the time it took before rating very unpleasant or higher, did not differ between the tolerance groups when the degree of strength of self-efficacy beliefs was introduced as a covariate. However, significant differences between groups after covariate analyses were observed for the final rating of sensation and the discrepancj' score of subjects' estimated exposure time. Thus, regardless of beliefs about how long they could tolerate the 69 cold water, tolerant subjects still had lower ratings of sensation at the end of their experience than did intolerant subjects. Less tolerant subjects anticipated more distress and amplified the sensation of the stimulus. On the one hand, these results support the idea that low tolerant subjects were more affectively distressed and report more pain sensations faster than tolerant subjects. On the other hand, these results also suggest that the degree of subjective pain may be more a function of the level of the belief of self-efficacy to withstand the pain in the situation. These results are consistent with past research (e.g., Dolce, Doleys, Raczynski, Lossie, Poole & Smith, 1986) in which data suggested that observed levels of self-efficacy expectancies are better predictors of tolerance levels than subjective pain ratings. Bandura (1986) also argued that the more self-efficacious a person judges him or herself to be, the less they report pain and discomfort. Thus, consistent with past observations, it appears that the strength of personal self-efficacy beliefs to withstand pain are influential factors in moderating pain self-report. Cognition and Pain Tolerance This investigation was designed to permit an evaluation of cognitive reactions to acute pain and whether they characterize different tolerance groups. Subjects differed in the type of cognitive events that occurred during their experience of pain. The results supported the hypothesis that subjects who clustered into the low pain tolerance group (i.e. endured cold pressor immersion less than 175 seconds), would engage in less efficacious coping with pain than subjects who were endured for a longer period of time. Intolerant subjects appeared to engage in more maladaptive or dysfunctional cognitions concerning their pain. In a retrospective interview of the cold pressor experience, relative to tolerant subjects, intolerant subjects reported more cognitions reflecting catastrophising thoughts, or wishes of miraculous escape from the pain during the cold water immersion. This result is similar to that reported by Reesor and Craig (1988) who found that CLBP patients with incongruent physical 70 symptoms also reported more catastrophising cognitions during an acute pain task. Differences between the pain tolerance groups also emerged on the post-task interview cognitive cluster score reflecting the use of coping strategies, even when differing strengths of self-efficacy beliefs were taken into consideration. The cluster score from the post-task interview reflecting catastrophising cognitions failed to reach significance when self-efficacy was introduced as a covariate. Thus, the degree of maladaptive coping may be more a function of the strength of the self-efficacy beliefs of the subjects in their ability to withstand pain. Pain has been recognized as a signal of actual or potential tissue damage (Melzack & Wall, 1983). Cognitive processes that accentuate the distress associated with pain may predispose some individuals to more readily evaluate their pain as a signal of tissue damage. Those individuals with cognitive processes that accentuate the distress may be more likely to avoid persisting in situations involving pain than those with cognitions that facilitate coping and pain endurance. A cycle of negative reinforcement and heightened fear of pain, may be enhanced by such dysfunctional thought processes and may lead to quicker avoidance or withdrawal from painful activities (Letham, Slade, Troup & Bentley, 1983; Slade, Troup, Lethem & Bentley, 1983). The results of the present study highlight this consistency between amplification of sensation and distress, presence of maladaptive cognitive responses, low frequency of occurrence for coping responses and low pain tolerance. A second way in which cognitive processes may affect pain tolerance is through the person's beliefs of self-efficacy in their ability to withstand the pain. However, retrospective responses reflecting a sense of control from the Coping Strategy Questionnaire and cognitions of control from the in-vivo assessment did not significantly differ between the tolerance groups. This may have been a reflection of their indirect relevance to the task at hand, the cold pressor exposure. Conversely, scores from the self-efficacy questionnaire which referred specifically to how long subjects estimated they could endure the ice cold water and provided 71 ratings of the strength of their convictions were more directly relevant to the cold pressor task. Thus, the significant results concerning these self-efficacy scores may be more pertinent to this discussion. Bandura (1977, 1982, 1986) has made the distinction between an efficacy belief and the strength of that belief. Self-efficacy expectancies are believed to function as mediators of behaviour however, a weak sense of efficacy is argued to be less adaptive than strong expectancies for reducing avoidance behaviour. The strength of the specific efficacy expectancy is also argued to determine how much effort individuals will exert and how persistent they will be in dealing with stressful situations (Bandura, 1977, 1986). The results of the present study were consistent with findings from previous research that individuals with weak efficacy expectancies are less likely than individuals with strong expectancies to persist in such responding in the presence of aversive experiences (e.g. Bandura, 1977, 1982, 1986; Dolce, 1987). Presumably, pain intolerant subjects lacked the conviction that the strategies they had at their disposal would be efficacious in facilitating coping or attenuating painful or distressing sensation. Alternatively, these subjects may have had a history of being ineffective in implementing coping strategies. Self-efficacy expectancies are believed to be strengthened from mastery experiences (Bandura, 1977, 1982, 1986). Low tolerant subjects may be those individuals who have used their coping skills too inconsistently, or may have engaged in catastrophising despite attempts to engage in coping. A final result stemming from this investigation that deserves comment is that relative to other variables, the number of sentences in the post -cold pressor interview was the most important discriminator between pain tolerance groups. Both tolerant and intolerant subjects had equivalent numbers of sentences at pre-task interviews however, following the cold pressor task, tolerant subjects were considerably more verbose in the total length of their interviews. The apparent difficulty of some individuals to communicate and express themselves, particularly when emotions are involved, has received more attention in the past few years due to the evidence that such characteristics have been 72 implicated in other medical and psychological syndromes, more specifically, depression and chronic pain. Sifneos (1973) reported a prevalence among patients who suffered from various psychosomatic diseases, of a relative constriction in emotional functioning, poverty of fantasy life, and an inability to access appropriate words to describe their emotions. Sifneos called these characteristics "alexithymic" (derived from the Greek compound meaning "a lack of words for emotions or moods"). The predominant feature of alexithymia is a communicative style in which feelings, attitudes and desires are not revealed (Nemiah & Sifneos, 1970). A recent study (McDonald & Prkachin, 1988) examined the validity of this concept for nonverbal expression. Their results suggested that deficits in spontaneously expressed facial activity also play a role in the definition of this phenomenon. Emotional overcontrol frequently characterizes patients with chronic pain and patients with major depression. Evidence for this relationship has been presented by numerous investigators. For example, Keefe et al. (1986) found that the number of depressive symptoms present predicted many aspects of the subsequent, pain experience. Beutler et al. (1986) propose that, the two conditions share a common pattern of disturbance in the process of expressing or blocking intense affect. The role of ease of expressing emotions for therapeutic change in disease states has begun to gain empirical support. This pattern is often cited as evidence that these two syndromes are psychological equivalents (Blumer & Heilbronn, 1982). However, clear cut conclusions on the extent and nature of the relationship can not be made and chronic pain and depression are best viewed as independent phenomena (Craig, in press) that share certain characteristics. From a series of recent studies, Pennebaker (Pennebaker & Hoover, 1986; Pennebaker & O'Heeron, 1984) concluded that people who discuss emotionally laden events have lower long-term probabilities of incurring stress-related disease than those who do not confide in others or who have difficulty expressing the emotions. Despite the tangential nature of the latter literature review, it is tempting to make an inferential leap from the present investigation's results concerning the attenuated loquaciousness of intolerant subjects and illness-vulnerable patients who demonstrate marked 73 deficiencies in expression of emotions and difficulties in finding appropriate descriptors of their experience. Such findings, in spite of their correlational nature, have implications for pain patient management and therapy. This study's results indicated that just as intolerant subjects verbalize less when asked to recount their thoughts and feelings during their immersion, the frequency of occurrence of their reported coping strategies was also lower than tolerant subjects, and the proportion of the total interview that the self-report of cognitions occupied was much smaller relative to the lengthier and richer samples of cognitive 'events' reported by tolerant subjects. Individuals who are better able to utilize effective coping strategies are also able to express their emotions and feelings regarding their pain experience. It was hypothesized that levels of state anxiety would influence the pain tolerance of the subjects. The lack of significant findings confirm some researchers conclusions that knowledge of anxiety level alone is insufficient (Weisenberg, 1987). It is possible that anxiety, when in conjunction with other key variables such as attitudes and past experiences may be a more salient predictor of pain response. It is also possible that a different set of variables may be important predictors of pain tolerance but it appears necessary to separate state from trait anxiety as they may have different outcome implications (Taenzer, Melzack & Jeans, 1986). Taenzer et al.(1986) examined the relationship between post-operative pain and a number of personality, affective and demographic factors. They found that high levels of trait anxiety and neuroticism were associated with high pain perception. Moreover, these two factors together were the most important predictors of pain. In contrast, situational anxiety and fear of surgery, were not correlated with pain measures, nor did they contribute to predictions of pain levels. They concluded that while a patient's pre-operation emotional state is a factor related to post-operation state, the patient's pain perception is more highly related to • dispositional or typical emotional reactivity. This may account for the findings in the present investigation in which only the state anxiety of the subject was assessed. On the other hand, one can not ignore other possible confounding factors that may have influenced the relationship between anxiety and pain tolerance. Prior to signing the consent form and 74 completing the STAI questionnaire, subjects were informed that the procedure would not cause physical damage to them and, that they could terminate the experience at any time. This is quite a bit different than clinical settings in which the noxious stimulus is not under as much control as in the laboratory. State anxiety levels may not have been as salient in this laboratory setting as in clinical situations. Moreover, the mean state anxiety rating for the sample of subjects in the current study was no different than the norm state anxiety rating for female undergraduates reported by Spielberger et al. (1970). Thus, in this investigation, the insignificant results for anxiety level may have been due to the fact that the subjects' anxiety was not necessarily a direct result of the immediate experimental situation. Facial Expression of Pain Another aim of this research was to evaluate whether the tolerance groups would be associated with characteristic facial activity. Nonverbal expression has become recognized as an important mode of communication, especially for pain. As a prior condition for assessing this possibility, it was necessary to determine whether specific AU categories were associated with exposure to the noxious stimulus (i.e., AU's significantly more prominent during exposure to the noxious stimulus as compared to baseline). Six A U categories were found to occur more frequently during the cold pressor period: AUs 4 (brow lowerer), 10 (upper lip raise), 12 (lip corner pull), 14 (dimpler), 25 (lips part), and 45 (blink). The current results are consistent with those of previous studies which have examined facial expressions of pain, with the exception of the presence of AU 6 (cheek raiser) which did not occur with sufficient frequency to remain after exclusion criteria were applied (Craig & Patrick, 1985; Hyde, 1986; LeResche & Dworkin, 1988; Patrick et al. 1986; Swalm, 1987). Before discussing in greater detail the analyses involving the 6 AUs isolated from the frequency data, two points should be noted. First, these facial movements were not displayed by all 60 subjects during the cold pressor videotape segments; individual differences in the 75 frequency of occurrence were considerable. It is important to mention that the brief interval coded, 3 seconds for each of the 5 videotape segments, is a relatively severe test. A second issue to address is whether the subjects were in fact experiencing pain and thus, the AUs observed to be more frequent during the cold pressor exposure were facial expressions of their pain. To some extent this point refers to the classic issue of "sensitivity" (i.e. does the expression, or the set of AUs pick up all instances of pain?) more commonly used in making diagnostic judgements. To determine if the subjects were experiencing pain during their exposure to the cold water one need only examine the physiological information pertinent to the cold pressor task. Lewis (1929) observed that phasic vasoconstriction and vasodilation occur during the course of hand immersion in ice water. Since then, various researchers (e.g. Kunckle, 1949; Teichner, 1965) have verified that the cyclic vasoconstriction is associated with the perception of pain. Conversely, cyclic vasodilation (the Lewis effect) is associated with numbness and diminution of pain, but does not usually begin until after a substantial period of exposure - in most cases, between 270 and 400 seconds (Teichner, 1965), although some subjects may not manifest it at all. In the present study, exposure to the cold water was limited to 300 seconds thus, we can be reasonably confident that subjects were experiencing pain during their exposure to the ice cold water. Furthermore, subjects were asked to rate how much pain they had experienced in the post-test questionnaire (Appendix H). The mean response rating for all 60 subjects to this item on a scale ranging from 0 to 6 was 5.1 (S.D. 1.02) indicating that nearly all subjects found the experience to be extremely painful. Thus, one can infer with reasonable confidence, that these AUs occurring more frequently during the cold pressor exposure, are a sensitive reflection of facial pain activity. It is important to note that changes in facial expression may have been affected by variables other than the noxious stimulus during the cold pressor segments. One can best understand this issue if one looks at the complex social context of the experiment and the tasks required of the subject. Subjects provided ratings of both their discomfort and sensation 76 during the cold pressor test. One could argue that this decision-making task may have affected their facial expressions. However, the mean response of all subjects to the post-test questionnaire item 1 which asked subjects to estimate how difficult it was for them to make their ratings during their exposure using a 7-point scale was 3.02. This suggests that most subjects did not find the rating requirement overty demanding. Although we can not rule out this extraneous factor, we can assume that an undemanding task is less likely to provoke confounding or idiosyncratic facial expressions other than those reflecting the effects of the stimulus experienced. Thus, for the sake of the discussion of these results, I have chosen to call these 6 AUs (4, 10, 12, 14, 25, and 45) "pain" AUs. The current results are consistent with those of previous studies which have examined facial expressions of pain (cf. Craig & Patrick, 1985; LeResche & Dworkin, in press; Swalm, 1987). Pain A U Analyses Having concluded that a specific pattern of facial activity was associated with the experience of pain, analyses appeared justified to determine whether tolerant and intolerant subjects were differentially facially active during their cold pressor exposure and whether there were changes in facial expression over time. The findings were unexpected since tolerant subjects displayed as much pain as less tolerant subjects. The six pain AUs identified in the present study were used as dependent variables. Facial pain activity indices were derived from linear combinations of the weighted AUs. Facial pain activity measures for the cold pressor segments were derived. In the first set of analyses, the aim was to determine whether indices of facial pain activity using appropriately weighted sums of AU frequencies were systematically influenced by the independent variable in the study (pain tolerance group) or varied at different points during the cold pressor exposure (the segment factor). No significant results were obtained for any of these analyses using the facial pain activity indices. These findings were unexpected. One would have anticipated differing facial expressive activity depending on tolerance group Figure 4 Facial Pain Activity Indices Over Time 78 Figure 5 Sensory Intensity and Affective Discomfort Ratings Over Time 50 T Segment 79 membership, i.e., those subjects with short endurance times to display a greater frequency of facial activity. It would appear that facial activity was more closely associated with self-report that the duration of exposure (although not all of the segments were based on comparable self-report). Inspection of the data indicated that in general, facial activity indices increased over time in a similar fashion to self-report ratings (see Figures 4 and 5). This study was not designed to allow a test of this association however, the most powerful test to assess this would be when time was constant for all subjects, but self-report differed substantially. Further analyses found an overall group difference among the segments for the 6 individual, equally weighted AUs. The action unit that varied in frequency to the greatest extent across the segments was AU 45 (blink). This action unit occurred more frequently in segment 5 than in segments 4 or 3. A U 45 was also associated with a large negative weight for the principle component from the PCA analysis (Table 3). This finding is consistent with Swalm's (1987) weights for the action units derived in a similar fashion. Thus, it could be argued that A U 45 is in fact not a specific "pain" AU, in the same sense as the other 5 AUs comprising the facial pain activitj' measure despite the fact that it occurred frequently during the cold pressor exposure. Researchers have argued that eyeblink frequency may be a measure reflecting some inner state or process. Attentional and response requirements of a task are important factors that can affect eyeblink production. Additional significant contributions of variability in blinking are such organismic variables as alertness and arousal, fatigue, and anxiety (Stein, Walruth & Goldstein, 1984). A review of the available evidence indicates that blinking frequency decreases during intense visual concentration (Hall & Cusack, 1972) and increased attention paid to a task (Baumstimler & Parrot, 1971; Telford & Thompson, 1933; Carpenter, 1948). Conversely, eyeblink increases occur during periods of "mental excitement" such as sudden, experimentally induced anger (Ponder & Kennedy, 1927) and are associated with 80 increases in stress and/or arousal (Appel, McCarron & Manning, 1968; Ekman, 1985; Stein, et al., 1984). The initial response to cold pressor pain probably induces startle, orienting behaviours and expressions of pain and affective discomfort (Patrick et al. 1986). This initial "shock" could account for heightened arousal and increased eye blinking (Hager & Ekman, 1985). Later as the exposure progresses, eye blink frequency drops significantly at the 30 second mark of the exposure and also in the 3 seconds just before choosing a rating of very unpleasant or higher. This is perhaps not surprising when one considers the demands of the rating task, which required the subjects to orient toward the panel in front of them, quickly scan the two scales, select words which described their situation and then perform a motor response by pushing the corresponding buttons on the panel. This task although not difficult as indicated by their responses to the post-test questionnaire, would require some effort and concentration on the part of the subject when called upon to rate. Thus, it follows from the literature review, that there would be a decrease in the rate of eyeblinks at these times (e.g. Baumstimler & Parrot, 1971; Hall & Cusack, 1972). Moreover, videotape segments often just preceded the actual rating. The literature also indicates that during a task that requires concentration at different intervals, blinks tend to occur during the moments of decreased attention (Stern et al., 1984) that is, in the intervals when they are not required to rate. Inspection of subject self-report at the last rating before termination reflected considerable sensation and discomfort. It is not unreasonable to assume that subjects are highly aroused and feeling anxious at this point in time. According to the literature, one would expect a higher frequency of eye blinking (Stein et al., 1984). Thus, in accordance with past findings, the endogenous eye blink (AU 45) may well be a mirror of attention and arousal factors, independent of other facial action units. Although the exact reason for endogenous eyeblinks (i.e., the rapid closing and reopening of the eyelid in the absence of identifiable external stimulation or irritation, is not well understood (Hall & Cusack, 1972), this action 81 appears to represent a separate category of facial activity from those previously identified AUs, that persists or increases in frequency throughout a painful ordeal (Craig & Patrick, 1985; LeResche & Dworkin, 1984) according to the demands of the task. In contrast to Craig and Patrick's (1985) findings that some pain AUs occur more frequently during the first ten seconds of the cold pressor exposure than during later points, the present study's insignificant findings for the other AUs and the reversed trend, that facial activity increases over time, could be argued to be a result of the brief segment width chosen (i.e. 3 seconds). One could argue that the full spectrum of facial pain activity associated with the cold pressor, especially this initial intense reaction, was not observed due to the brief interval coded. To address this concern, a supplementary analysis was carried out to examine whether there were differences in frequency of occurrence of the pattern of facial activity if the videotape segment to be coded was lengthened to encompass the span chosen by Craig and Patrick (1985). The facial pain activity index for the initial three seconds (i.e. the segment used in the current study) was contrasted against facial pain activity indices calculated for two other 3 second segments (i.e. seconds 4,5,6 and seconds 7,8,9) for a random selection of 20 of the 60 subjects. The results indicated that the amount of facial activity present in the initial 3 seconds of cold pressor exposure was not different from facial activity occurring in the later segments. The ANOVA summary table is presented in Appendix N. Means and standard deviations for each of the individual AUs at each of the three segments are presented in Table 14. From these results we can be quite confident that the original segment width of 3 seconds encompassed a representative sample of facial activity and that the low frequency occurrence of AUs, especially during the initial time of exposure to the cold water was not due to the brief interval coded. Table 14 82 Mean Frequency of Occurrence of Action Unit Categories During Initial Nine Seconds of Cold Pressor Exposure Frequency Data Segment 2a 2b 2c Descriptor M SD M SD M SD Brow Lowerer 0.05 0.224 0 0 0 0 Upper Lip Raise 0 0 0 0 0 0 Lip Corner Pull 0.20 0.52 0.05 0.22 0 0 Dimpler 0.05 0.22 0 0 0.05 0.22 Lips Part 0.50 0.61 0.60 0.75 0.40 0.50 Blink 0.85 0.88 0.45 0.83 0.80 0.77 N=20 Note: Segment 2a refers to sees 1, 2,3 of cold pressor exposure Segment 2b refers to sees 4, 5, 6 of cold pressor exposure Segment 2c refers to sees 7, 8,9 of cold pressor exposure 83 Although these results do stand in contrast to those of Craig and Patrick (1984), one possible reason for the discrepancy deserves some mention. The influence of differing methodologies is suggested by the lack of concordant findings. Craig and Patrick's (1985) study involved a social modeling paradigm which relied upon a confederate present in the room as the experiment took place. Other methodological differences between the studies may have varying impacts upon the behaviour of the subjects. Moreover, the experimenter in that study was a male and the subjects were all females, whereas in the present study, the experimenter was a female and the subjects all females. Future research would need to investigate the impact of the sex of the experimenter upon subject responses. Another possible confound that might have affected subjects' overt behaviour was the covert videotaping procedure. Although this study was designed so that subjects would remain unaware of the observation technique, it is possible that there were some subjects who were not naive to the experimental procedure (e.g. from past experiences with other experiments etc.) and who may have suspected they were being observed in some fashion. This is a potential source of bias in any study employing covert observation techniques no matter how sophisticated. A manipulation check on the post-test questionnaire asked subjects to indicate on a 7 point scale how aware they were of being observed during the experiment. The mean response to this question was 0.55. Thus, we can be reasonably confident that the videotaping procedure was not an influential factor biasing subjects' facial expressions. The relationships among the cognitive variables and the measure of facial activity for the cold pressor experience was assessed. Only two cognitive measures were strongly associated with the measure of facial activity: the coping cluster score from the post-test structured Interview, and the number of sentences in the post-test. Both these measures were negatively correlated with facial activity. It would appear that subjects who display high levels of facial activity are less likely to report the use of coping techniques after a pain induction task. Moreover, the subjects with high facial activity are also those who have a 84 paucity of detail in their post-test interviews. Future research would be necessary to explore this association between cognitive and behavioural indices of pain to determine the extent and the consistency of such a relationship. Cognitive Assessment of Pain As previously suggested (Merluzzi et al., 1981), different types of cognitive assessment methods may produce different results. In this study, a cued, prospective and retrospective account of cognitive events in an acute experimental pain session revealed different kinds of cognitive activity. These results demonstrated that cognitive 'samples' could be reliably and relatively easily coded and provide meaningful data. Cognitions sampled from the structured interview were different than those revealed in a self-report, retrospective questionnaire that tapped a longer time frame. Conceptually, similar kinds of pain related cognitions were not correlated between these measures, with the exception of coping which was only moderately correlated. The lack of correspondence in the measures may reflect the different foci of the two measures. The structured interview was aimed at tapping cognitions associated with the immediate pain experience; whereas, the Coping Strategies Questionnaire had a broader more retrospective focus for coping with pain which may not have been relevant for this sample of subjects. The cognitions that differentiated the two tolerance groups were those that were directly related to the noxious stimulation. This may mean that the cognitions sampled in an experimental setting have no relevance to more t3^ pical cognitive characteristics of the subjects in dealing with pain especially if they are non-pain patients and have had little exposure to chronic pain of one kind or another. Furthermore, caution must be exercised when making generalizations between pain-patient populations. Future analogue research should be cautioned from overgeneralizing results obtained from non-pain patients to pain patients and also from overgeneralizing the construct of pain-patient itself. However, such observations should not preclude research using cognitive-behavioural trials with pain patients. On the contrary, cognitive-behavioural trials have been demonstrated to be effective in sampling 85 cognitive coping styles (Turk et al., 1983) in the treatment of chronic pain disorders, and in discriminating subgroups of chronic low back pain patients (Reesor & Craig, 1988). It was hypothesized that prospective accounts emphasizing cognitive processes would not be consistent predictors of performance on the cold pressor task and would not correlate highly with post-task assessment of cognitions. However, this hypothesis was not confirmed; the pre and post task measures of cognitive strategies correlated highly with one another. This significant effect adds support to the assumption made by past researchers that cognitions assessed after a task are consistent examples of a person's cognitive processes. However, as discussed above, this consistency is evident only for an assessment that is focussed on the task at hand. Assessments that attempt to tap longer periods of time, such as the CSQ do not predict post pain performance or cognitive activity. Conclusions This investigation points to not only the necessity of assessing multiple measures that tap the different dimensions of pain, but also to the importance of measuring the strength of self-efficacy beliefs to withstand noxious stimulation in future research on psychological processes during pain in both analogue and clinical settings. While facial expressions of pain were identified during the cold pressor experience, thej* did not differ between pain tolerance groups in this study. Tolerance group differences emerged on other self-report variables. Low tolerant cold pressor pain subjects appeared less efficacious in their abilit}' to cope with pain and appeared to engage in dysfunctional catastrophising when experiencing pain. A tendency to rate the pain they were experiencing as more painful and affectively distressing was also observed in intolerant subjects. However, the differences in affective discomfort and the recalled amount of pain felt by these subjects appeared to be more a function of self-efficacy beliefs. The strength of the self-efficacy belief may possibly contribute to the utilization of either coping or catastrophising strategies that influence the pain response.' 86 Future research would be necessary to explore the factors that may have mediated the difference in facial activity results between this study and Craig and Patrick (1985). The cognitive-behavioural relationship that was suggested in this study also deserves study. Implications from this line of research are far reaching especially in the health care fields of behavioural medicine. Accurate diagnoses and effective management and treatment of chronic pain disorders as well as applications for treatment during more immediate interventions for patients suffering from acute pain states are some of the possible future ramifications of study of cognitive and behavioural correlates of pain responses. 87 REFERENCES Ahles, T.A., Blanchard, E.B., & Leventhal, H. (1983). 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The effects of imagery content, choice of imagery content, and self-evaluation on the self-control of pain. Cognitive Therapy and Research, 2, 225-240. 97 APPENDIX A FACS Action Units A U FACS NAME 1 Inner brow raise 2 Outer brow raise 4 Brow lowerer 5 Upper lid raise 6 Cheek raiser 7 Lid tightener 10 Upper lip raiser 11 Nasolabial deepener 12 Lip corner pull 14 Dimpler 20 Lip stretcher 23 Lip tight 25 Lips part 26 Jaw drop 27 Mouth stretch 43 Eyes close 45 Blink (Ekman & Friesen, 1978) 98 APPENDIX B Gracely Rating Scales SENSORY INTENSITY UNPLEASANTNESS Extremely Intense 59.5 Very Intolerable 44.8 Very Intense 43.5 Intolerable 32.3 Intense 34.6 Very Distressing 18.3 Strong 22.9 Slightly Intolerable 13.6 Slightly Intense 21.3 Very Annoying 12.1 Barely Strong 12.6 Distressing 11.4 Moderate 12.4 Very Unpleasant 10.7 Mild 5.5 Slightly Distressing 6.2 Very Mild 3.9 Annoying 5.7 Weak 2.8 Unpleasant 5.6 Very Weak 2.3 Slightly Annoying 3.5 Faint 1.1 Slightly Unpleasant 2.8 No Sensation 0 No Discomfort 0 (adapted from Gracely, McGrath, & Dubner, 1979) 99 APPENDIX C Perceived Self-Efficacy to Tolerate Pain Questionnaire Directions: Write "yes" or "no" in the space next to each goal, indicating whether you believe you will be able to achieve the specific goal during the pain task. Next, indicate on the scale provided how sure you are that you will achieve the specific goals. At this time do you think you can: 1. Tolerate 10 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderately completely uncertainty certain sure 2. Tolerate 20 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderately completely uncertainty certain sure 3. Tolerate 30 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderately completely uncertainty certain sure 4. Tolerate 40 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderately completely uncertainty certain sure 5. Tolerate 50 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 high moderately uncertainty certain 60 70 80 90 100 completely sure 6. Tolerate 60 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 high moderately uncertainty certain 90 100 completely sure 7. Tolerate 75 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 high uncertainty 20 30 40 50 60 70 80 90 100 moderately completely certain sure 8. Tolerate 90 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 high moderately uncertainty certain 80 90 100 completely sure 9. Tolerate 105 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 high moderately uncertainty certain 80 90 100 completely sure 10. Tolerate 120 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 101 0 10 20 30 40 50 high moderately uncertainty certain 60 70 80 90 100 completely sure 11. Tolerate 135 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderately completely uncertainty certain sure 12. Tolerate 150 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 high moderately uncertainty certain 60 70 80 90 100 completely sure 13. Tolerate 165 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 high moderately uncertainty certain 70 80 90 100 completely sure 14. Tolerate 180 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderately completely uncertaintj' certain sure 15. Tolerate 200 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 102 0 10 20 30 40 50 60 high moderately uncertainty certain 70 80 90 100 completely sure 16. Tolerate 220 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 high moderately uncertainty certain 90 100 completely sure 17. Tolerate 240 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderate^ completely uncertainty certain sure 18. Tolerate 260 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 high moderately uncertainty certain 70 80 90 100 completely sure 19. Tolerate 280 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 . 70 80 90 100 high moderately completely uncertainty certain sure 20. Tolerate 300 seconds cold water ? (yes or no?) How likely is it that you will achieve this goal? Put an X on the scale. 0 10 20 30 40 50 60 70 80 90 100 high moderately completely uncertainty certain sure 104 APPENDIX D Coping Strategy Questionnaire The CSQ described by Rosenstiel and Keefe (1983) consisted of seven scales, 6 concerning cognitive activity and 1 concerning behavioural activity during the experience of pain. Each scale consisted of 6 items. Patients rated each item on a 7-point scale where: the '0' anchor indicated that the cognitive or behavioural activity was "never" characteristic of their experience during pain; the '3' anchor indicated that the cognitive or behavioural activity was "sometimes" characteristic of their experience during pain; the '6' anchor indicated that the cognitive or behavioural activity was "alwaj's" characteristic of their experience during pain. The seven scales have been listed below along with representative items: 1. Diverting attention: I count numbers in my head or run a song through my mind. I think of people I enjoy doing things with. 2. Reinterpreting the pain sensations: I don't think of it as pain but rather as a dull or warm feeling. I just think of it as some other sensation, such as numbness. 3. Catastrophising: I worry all the time about whether it will end. I feel like I can't go on. 4. Ignoring sensations: I don't pay any attention to it. I just go on as if nothing happened. 5. Praying or hoping: I pray to God it won't last long. I have faith in doctors that somedaj' they can cure my pain. 6. Coping self-statements: I tell myself that I can overcome the pain. No matter how bad it gets, I know I can handle it. 105 7. Increased behavioural activities: I try to be around other people. I do something I enjoy, such as watching TV or listening to music. In addition to these seven scales, the CSQ also contained two items concerning the • effectiveness of patients' efforts to cope. Patients were also asked to rate, on 7-point scales, the amount of control they had over their pain and the extent to which they were able to decrease their pain. 106 APPENDIX E Coping Strategy Questionnaire (adapted from Rosenstiel and Keefe, 1983) Individuals who experience pain have developed a number of ways to cope or deal with pain. These include saying things to themselves when they experience pain, or engaging in different activites. Below are a list of things that people have reported doing when they feel pain. For each activity, please indicate, using the scale below, how much you engage in that activity when you feel pain, where a 0 indicates that you never do that when you are experiencing pain, a 3 indicates that you sometimes do that when you experience pain, and a 6 indicates you always do it when you experience pain. Remember, you can use any point along the scale. 0 1 2 3 4 5 6 Never Sometimes Always WHEN I FEEL PAIN... 1. I try to feel distant from the pain, almost as if the pain was in somebody else's body. 2. I leave the house and do something, such as going to the movies or shopping. 3. I try to think of something pleasant. 4. I don't think of it as pain but rather as a dull or warm feeling. 5. It is terrible and I feel it is never going to get any better. 6. I tell myself to be brave and carry on despite the pain. 7. I read. _8. I tell myself that I can overcome the pain. 9. I count numbers in my head or run a song through my mind. 10. I just think of it as some other sensation, such as numbness. 11. It is awful and I feel it overwhelms me. 12. I play mental games with myself to keep my mind off the pain. 13. I feel my life isn't worth living. 14. I know someday someone will be here to help me and it will go away for awhile. 15. I pray to God it won't last long. 16. I try not to think of it as my body, but rather as something separate from me. 17. I don't think about the pain. 18. I try to think ahead, what everything will belike after I've gotten rid of the pain. 19. I tell myself it doesn't hurt. 20. I tell myself I can't let the pain stand in the way of what I have to do. 21. I don't pay any attention to it. 22. I have faith in doctors that they can cure my pain. 23. No matter how bad it gets, I know I can handle it. 24. I pretend it is not there. 25. I worry all the time about whether it will end. 26. I replay in my mind pleasant experiences. 27. I think of people I enjoy doing things with. 28. I pray for the pain to stop. 29. I imagine that the pain is outside of my body. 30. I just go on as if nothing happened. 31. I see it as a challenge and don't let it bother me. 32. Although it hurts, I just keep going. 33. I feel I can't stand it any more. 34. 1 try to be around other people. 35. 1 ignore it. 36. I rely on my faith in God. 37. I think of things I enjoy doing. 38. I feel like I can't go on. 39. I do anything to get my mind off the pain. 40. 1 do something I enjoy, such as watching TV or listening to music. 108 _41. I pretend it is not a part of me. 42. I do something active, like household chores or projects. Based on all the things you do to cope or deal with your pain, on an average day, how much control do you feel you have over it? Please circle the appropriate number. Remember, you can circle any number along the scale. 0 1 2 3 4 5 6 No control Some control Complete control Based on all the things you do to cope, or deal with pain, on an average day how much are you able to decrease it? Please circle the appropriate number. Remember, you can circle any number along the scale. 0 1 2 3 4 5 6 Can't decrease it at all Can decrese it somewhat Can decrease it completely I l l APPENDIX H Post-test Questionnaire Name: Please complete the questionnaire based on your participation in this study. Please circle the number which best describes your oppinion or fill in the blanks where appropriate. 1. How difficult was it for you to rate your discomfort? 0 1 2 3 4 5 6 very easy moderately very easy difficult 2. How painful was the cold water stimulus at its most intense period? 0 1 2 3 4 5 6 not painful moderately extremely at all painful painful 3. To what extent were you aware that you were being videotaped during the experiment? 0 . 1 2 3 4 5 6 not aware very aware 4. What things made you aware of the videotaping? 5. To what extent did your awareness of the videotaping procedure affect your behaviour during the experiment? 0 1 2 3 4 5 6 not at all somewhat considerably 6. To what extent did the self-reports of pain during the immersion affect your your pain tolerance? 0 1 2 3 4 5 6 not at all somewhat considerably 7. If you felt that the ratings affected your performance please give some reasons why. In your estimation, how long was your hand immersed in the cold water bath? minutes seconds Thank-you for your cooperation 113 APPENDIX I Structured Interview Schedule for Pain The interview, adapted from Genest (1978), begins as follows: (note: for subjects interviewed prior to the task the tense is changed) ONE OF THE THINGS WE ARE INTERESTED IN IN THIS EXPERIMENT IS WHAT PEOPLE ARE FEELING AND THINKING ABOUT WHILE THEIR HAND IS IMMERSED IN THE COLD WATER. I AM GOING TO ASK A FEW QUESTIONS ABOUT ANY THOUGHTS, FEELINGS OR ANYTHING THAT OCCURRED TO YOU WHILE YOUR HAND WAS IN THE COLD WATER AND I WOULD LIKE YOU TO ANSWER IN AS MUCH DETAIL AS YOU CAN. OK? TRY TO IMAGINE YOURSELF BACK DURING THE FEW MOMENTS JUST BEFORE YOU PUT YOUR HAND INTO THE COLD WATER TANK. TELL ME EVERYTHING YOU CAN REMEMBER ABOUT WHAT YOU WERE THINKING AND FEELING AT THAT TIME, EVEN IF YOUR THOUGHTS WERE BRIEF OR RANDOM, AND EVEN IF THEY SEEM TRIVIAL. Reflect each of the subject's items in turn, paraphrasing them briefly when the subject pauses. If the subject has provided more than three items, reflect the first, some representative sample of the following ones, and the last item. At any point, if the subject reports having done something non-cognitive (e.g.,"looked at the tape recorder", "looked away", "tapped my knee"), respond with, "WHAT WERE YOU THINKING WHILE YOU... (looked at the tape-recorder, etc.)". Prompt if necessary. See note 1. Then ask: IS THERE ANYTHING ELSE? Repeat this question until the subject reports no new cognitions that occurred before the hand was immersed. Then proceed: ONCE YOU HAD PUT YOUR HAND IN THE WATER, WHAT KIND OF FEELINGS AND THOUGHTS DID YOU HAVE THEN? Prompt if necessary. Then repeat until no further responses are given: AFTER THAT, WHAT CAN YOU REMEMBER? And, until no further cognitions are reported, ask: IS THERE ANYTHING ELSE? 114 When subject reports they can recall no further information: AS YOU WERE SITTING THERE, WITH YOUR HAND IN THE COLD WATER, GIVING REPORTS FROM TIME TO TIME, WHAT ELSE DO YOU RECALL EXPERIENCING, ANY THOUGHT, FEELING, IMAGE; EVEN FLEETING OR RANDOM? Finally, ask: WHAT DO YOU REMEMBER THINKING ABOUT OR FEELING JUST BEFORE YOU TOOK YOUR HAND OUT OF THE WATER? Again, until the subject reports no new cognitions, repeat: IS THERE ANYTHING ELSE? NOTE 1: If the subject (1) reports being unable to recall anything when a question is posed, or (2) responds to a question very briefly or with apparent difficulty in either formulating a response or remembering, then prompt with a question such as one of the following: WHAT WERE YOU THINKING ABOUT? HOW WERE YOU FEELING? WAS THERE ANYTHING ELSE GOING ON? CAN YOU TELL ME MORE ABOUT THAT? If these prompts are insufficient to elicit more than a minimal response from the subject, then assist by "painting a picture" in more detail by describing specific aspects of the situation. NOTE 2: If it is unclear whether a statement made during the interview is meant to be a report of a cognition that occurred during the pain pressure task or is simply something that the subject is thinking of during the interview, the ambiguity should be resolved by a question such as: WERE YOU THINKING ABOUT THAT THEN (DURING THE COLD PRESSOR TASK)? Request additional clarification if necessary. 115 APPENDIX J SISP Scoring Key The spontaneously reported cognitions are coded on a 5-point scale for each of the 6 categories from Genest (1978). The 5-point rating scale has the following anchors: 1. No occurance of the thought/feeling category 2. Some elements of the thought/feeling category 3. At least one clear occurance of the thought/feeling category 4. Multiple examples or implication that this thought/feeling categorj' was more than an isolated cognitive event 5. Implication that the thought/feeling category predominated mental activity The categories, adapted from Genest (1978), were defined as follows: 1. Dissociates Pain From Self (a) Statement or implied meaning that the pain is limited to one part of the bodj7 with the implication or explicit statement that this limitation made the pain less aversive or bothersome. Examples: "My mind was calm; it was just my hand that was hurting". "I just thought about how comfortable I was in the rest of my body. My hand wasn't going to bug the rest of me". (b) Report of "objectively observing" or attempting to objectively observe sensations in the painful part with some detachment (i.e., negative affect is not salient). Examples: "I think I was trying to feel the pain, to think about what was going on in this hand". "I was feeling the sensations, the throbbing and the numbness; looking at my finger and feeling it". (c) An expression of distance from the sensations, either physical or psychological. Examples: "The pain seemed far away, not really bothersome". "It seemed my arm was experiencing something irrelevant, unimportant". (d) A report of not thinking or "thinking about nothing". 116 Examples: "I tried not to think". "It felt like nothing was coming, no input, just sort of an emptiness". 2. Relaxation Score if the subject referred to being drowsy, relaxed, at ease or in a similar state, either physically or mentally. Examples: "I felt calm, just took it easj'". "I took a deep breath and felt the tension drain away for awhile". "I just tried to relax". 3. Imagery Score for mention of an image, either from memory or fantasy, that does not include pain, or includes pain but without negative affect. Examples: "I was just imagining that I had smashed my hand and was lying on a hopsital bed being taken care of by nice nurses". "I was planning my summer trip home, thinking of all the details". 4. Non-Imagery Distraction Score for any thought or feeling not related to the pain, or an attempt to ignore or distract attention from the pain, that does not constitute an image (see 3 above). Examples: "I was going over my appointment schedule for tomorrow". "I kept my thoughts on the sounds from the corridor". "I was tapping my foot". 5. Sense of Control Expressed (a) A statement that the patient could, or felt able to control physical sensations or degree of painfulness. Examples: "I thought it would be possible to just not think about it; then it shouldn't realty bother me; it wouldn't hurt me as much". "I felt I could reduce the pain if I tried". (b) A deliberate attempt to use some strategy or technique to affect the sensations, or the attribution of some variation in the sensations, or painfulness, or awareness of sensations to some action of the patient. Just the use of a strategy is not sufficient: intention to affect the experience must be explicit or implicit (e.g., determined extensive or deliberate use, or statement of intent). Examples: "I was just trying not to concentrate on my hand, because sometimes when you're conscious about something you can increase your feelings in it". "I started to distract myself on my right leg. I thought that 117 would help". "When I looked at it it seemed that it hurt more than when I looked away so I turned away". "I was singing this song in my head, and then I noticed that it didn't bother me as much". BUT NOT: "I was just looking around the room". "I was bored and began thinking about a book I'm reading". (c) A statement that the subject could, or felt able to control her reactions to the sensations experienced, that is that she could persevere despite pain, or could tolerate the aversive stimulation. Examples: "Oh I can take this. I've got a good tolerance for pain. I think it's a snap". "I figured I could control myself..that it would be painful but what's a bit of pain? I could take it anyway". (d) A deliberate attempt to use some strategy or technique to affect reactions to the sensations, or the attribution of control of reactions to some action of the subject. Examples: "I was concentrating on saying to myself, 'You've got to keep it in; you've got to keep it in', and gritting my teeth, and biting my lip and pinching my leg..doing anything". "I was able to stay because I was thinking about how others had done, and that made me stay in longer". (e) Indication of being in control by being able to terminate. Example: "I knew I could stop whenever I wanted, so I just kept going". 6. Catastrophising (a) An expression of fear, anxiety, or other negative affect, or "worrythoughts" about possible dire outcomes. Examples: "I was afraid of what was going to happen to my hand". "I was thinking that there might be an electric curent or something in there". "I thought, 'This will hurt'". "I hate pain" (as a reported cognition). "I thought my arm might be damaged if I stayed too long". (b) Attention focused on or drawn to pain or other unpleasant feelings. Either: (i) a statement that the patient thought of little other than the pain, or could not attend to anything else; or (ii) reference to pain, discomfort, or unpleasant feelings, or attempts to escape from such events or both. Examples: "Except for the pain, I wasn't really thinking about anything else". "All I could feel was the pain". "I couldn't concentrate on anything else". "It's really bugging me now..It was starting to bug me there..Just trying to get away from the thought again...The pain was steady, you know, it was hard". 118 "I was thinking I should think about other things..I was trying not to think about it..It was bothering me more..When I looked at it, it hurt". (c) Termination thoughts The subject mentions having thoughts about termination or not terminating (as a conflict, not a resolved decision to stay). Examples: "All the way through, I was wondering, 'Well, should I stay a little longer'". "I was thinking, how long could I stand it..'I wish I could take it out'..kept encouraging muself to stay in". "I really wanted to take it out". "It crossed my mind to take it out, but I just didn't..thinking, 'God, I'd like to take it out'..I was saying to myself, 'You've got to keep it on'..I figured I'd be taking it off soon". (d) Indication of no control over sensations, painfulness, or reactions to sensations. Examples: "It (the subject's attempt to distract herself from the pain) didn't work. I couldn't concentrate on it". "I wondered whether I would feel a lot of pain anywaj' (despite attempts to control it)". 119 APPENDIX K Repeated Measures ANOVA Summary Table: Group Differences on Facial Pain Activity Measures Across Cold-Pressor Segments Source D.F. SS MS F _£ Tolerance 1 4.92 5.01 0.98 0.33 Segment 3 1.74 0.58 0.39 0.76 Tolerance X Segment 3 8.85 2.78 1.85 0.14 N = 60 120 APPENDIX L MANOVA Summary Table: Group Comparisons on Facial Action Units Across Cold-Pressor Segments Source Wilks Lambda •(s=l, M = 8, N=19 1/2) _F(18,41) _p_ Tolerance 0.87 1.34 0.256 Segment 0.37 3.91 0.0001 Tolerance X Segment 0.57 1.75 0.068 N = 60 .. Appendix M MANOVA Summary Table: Group Differences on Pre and Post-test Interview Scores Source Wilks Lambda (s=l, M = l , N = l l 1/2) _F(4,25) _D Tolerance 0.73 2.38 0.081 Time 0.70 2.70 0.054 Tolerance: X Segment 0.69 2.97 0.039 122 APPENDIX N Repeated Measures ANOVA Summary Table: Differences in Facial Pain Activity Measures During the Initial Nine Seconds of Cold Pressor Exposure Source D.F. . SS MS F _£ Segment 2 0.00 0.00 0.00 0.99 Within 38 11.51 0.30 N = 20 


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