Many individuals with movement disorders are unable to make efficient use of graphical computer interfaces commonly employed in personal computers. In this study, performance limitations in target tracking with a computer mouse were studied for eight young subjects aged 19 to 29 (M = 23, SD = 3), four old subjects aged 70 to 73 (M = 72, SD = 1), and five motor-disabled subjects aged 37 to 74 (M = 65, SD = 16). Subjects tracked simple one- and two-dimensional motions at various frequencies.

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... rmance was measured using an accuracy index derived from root-mean-square error, and a linearity index based on coherence estimation. A maximum bandwidth of 2 Hz for accuracy of mouse use was found, which often decreased due to advanced age or motor disability. Tracking linearity of all groups decreased as frequency increased. A significant degree of nonlinearity existed in all results (p < 0.05), with disabled subjects nearing complete nonlinearity in two-dimensional tracking. The data show that with advanced age and disability, mouse use becomes increasingly inaccurate and nonlinear. Assistive computer interfacing techniques, such as signal filtering, may improve mouse use.