UBC Theses and Dissertations

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UBC Theses and Dissertations

Usability and the effects of interruption in C-TOC : self-administered cognitive testing on a computer Brehmer, Matthew Michael


Cognitive Testing on a Computer (C-TOC) is a self-administered web-based computerised cognitive assessment battery. C-TOC's intended scenario of use involves an older adult, who has presented a concern regarding his or her cognitive health, completing the test independently at home, as directed by their family physician or a specialty clinic. This thesis presents the results of two studies aimed to address the viability of older adults completing the C-TOC test battery in a home setting, first to identify usability issues, and second to understand the effects of interruptions on C-TOC performance. In Study 1, an initial standard evaluation of C-TOC's usability was conducted with representative users and a cross-cultural advisory panel of health professionals. Based on our own observations of participants' interactions with C-TOC, together with subjective reporting measures (interviews, questionnaires, & focus group discussion), several user interface design issues were identified. Given these issues, this thesis presents a list of recommendations for improving C-TOC's usability in subsequent versions. The bulk of the novel contributions presented in this thesis arise from Study 2. In this study, we report the findings of a laboratory experiment to investigate the effects of increasingly demanding interrupting tasks on older adults' C-TOC testing performance. Related work has reported interruptions having a range of inhibitory and facilitatory effects on primary task performance. Cognitive ageing literature has suggested that increased interruption workload demand should have greater detrimental effects on older adults' performance, when compared to younger adults. With 36 participants from 3 age groups (19-54, 55-69, and 70+), we found divergent effects of increased interruption demand on two primary tasks. Results suggest that older and younger adults experience interruptions differently, that increased interruption demand can incur a task resumption cost. However, at no age is test performance, in terms of accuracy, compromised by demanding interruptions. This finding is reassuring with respect to the success of C-TOC, and is promising for other applications used by older adults. It is our hope that what was learned from both studies will contribute to the development of a usable and valid cognitive assessment test.

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