Matthew Brehmer

Abstract: Interruptions in the home pose a threat to the validity of self-administered computerised cognitive testing. We report the findings of a laboratory experiment investigating the effects of increased interruption workload demand on older adults' computerised cognitive test performance. Related work has reported interruptions having a range of inhibitory and facilitatory effects on primary task performance. Cognitive ageing literature suggests 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, 70+), we found divergent effects of increased interruption demand on two primary tasks. Results suggest that older and younger adults experience interruptions differently, but at no age is test performance compromised by demanding interruptions. This finding is reassuring with respect to the success of a self-administered computerised cognitive assessment test, and is likely to be useful for other applications used by older adults.

Abstract: A haptic icon is a short physical stimulus attached to a simple meaning, which provides information and feedback to a user. To scale the utility demonstrated for small icon sets to larger ones, we need efficient strategies to help users learn subtle distinctions among stimuli, in a modality for which they may not hold detailed descriptive percepts. This paper investigates the effect of naming haptic stimuli – i.e. explicitly creating a linguistic marker – on the accuracy with which users are able to identify, distinguish, and recall stimuli.

We conducted a between-subjects experiment using 60 participants equally divided among three naming conditions: no names, pre-selected non-descriptive names, and self-selected names. The experiment examined the impact of naming strategy on the ability of participants to identify stimuli in a nonverbal matching test, and on remembering stimulus names. For this challenging task and the degree of learning afforded, naming did not significantly impact accuracy of matching stimuli to meanings for all participants. However, more than twice of many of those allowed to choose names reported the ability to remember and distinguish stimuli than those required to use non-descriptive names, and many participants felt that the names were useful. Of middle-performing participants, the self-selected names group performed significantly better than the non-descriptive names group, and appeared to progress more quickly in learning. We summarize evidence for a trend that might widen with refined naming strategies and more extensive learning.

Abstract: Active games are video games that involve physical activity. Interaction in active games is captured via a variety of input devices such as accelerometers, cameras, pressure sensors and exercise equipment. It is difficult for programmers to deal with this profusion of devices, leading most active games to be tied to a particular hardware platform. In this paper, we introduce the GAIM toolkit. GAIM simplifies input handling in active games through a high-level API that abstracts the details of individual devices. This allows developers to write code independently of the input devices used, allows the toolkit to dynamically adapt to the devices a player has available, and allows people with different hardware to play together. We illustrate the approach through two active games developed using the GAIM toolkit.

Abstract: Active games are video games that involve physical activity. Active games capture input via a variety of devices such as accelerometers, cameras, pressure sensors and exercise equipment. Although active games have become highly popular, the interaction styles they support are poorly understood, and largely driven by the capabilities of individual hardware devices. In order to allow for a standard development approach, a better understanding of the interaction found in active games is required. We have investigated existing commercial and academic games in order to classify input for active games. Our classification abstracts input from hardware, providing a better understanding of the interaction itself. Our ultimate goal is to make it easier to develop active games independently of underlying input hardware.

Abstract: 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.

Abstract: We present two ongoing studies that are part of a larger multi-disciplinary research project which aims to design, develop, and implement a web-based computerized screening test for cognitive impairment, called Cognitive Testing on a Computer. A laboratory study is conducted to investigate the impact of interruptions on task performance among three different age groups. A qualitative field study is undertaken in older adults’ homes to examine potential interruptions and distractions that may be present as barriers to their performance when taking the assessment tool from home. Our initial findings indicate that technological interventions may help detect and mitigate interruptions for older adults.