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UBC Theses and Dissertations

Validation of the synactive theory of development : are body movements in preterm infants signs of stress? Holsti, Liisa


The synactive theory of development, a widely used theory which has revolutionalized the assessment and treatment of preterm infants in the NICU, consists of five principles which are applied through a model of care. This model, the Newborn Individualized Developmental Care and Assessment Program® (NIDCAP) directs developmental specialists to interpret preterm infant movements either as stress or stability cues. However, limited empirical validation of this dualistic classification system has been reported. The primary aim of this dissertation is to examine the validity of the NIDCAP® by studying the motor reactions of preterm infants in response to a continuum of stressor intensities which range from no stimulus to a painful stimulus. First, along with other valid biobehavioural measures of pain and in infants at 32 weeks corrected gestational age (GA), I examine the frequency of NIDCAP® movements during blood collection. Then, in a within subjects cross-over study (random order), I compare preterm infant biobehavioural pain reactions to responses during a tactile procedure. The secondary aim is to increase the accuracy and specificity of preterm infant pain assessment by determining whether NIDCAP® behaviours are reliable pain indicators and whether these indicators distinguish between pain and stress responses. Of the 26 NIDCAP® stress cues, 14 movements (flex arms and legs, extend arms and legs, hand on face, finger splay, fisting, salute, yawn, sit on air, frown, tongue extension, air plane, eye floating) are associated with intrusive and painful procedures. Finger splay, fisting and hand on face are particularly salient stress cues in infants born at earlier GA (< 30 weeks). Contrary to the NIDCAP®, twitches decrease during the stressor phases in both studies. In addition, in response to painful and tactile procedures, preterm infant body movements are often exaggerated, whereas facial responses are dampened. In conclusion, the dualistic classification of the NIDCAP® needs revision; it also should incorporate alternative explanations of preterm infant movements. The use of body movements as stress response indicators is promising; however, facial reactivity the most specific behavioural pain indicator in preterm infants. Future research is needed to refine further the measurement of stress responses in this vulnerable population.

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