EFFECTS OF AGE AND DISABILITY ON TRACKING TASKS WITH A COMPUTER MOUSE- ACCURACY AND LINEARITY

Many individuals with movement disorders are unable to make efficient use of graphical computer interfaces commonly employed in personal com puters. 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 m otor-disabled subjects aged 37 to 74 (M=65, SD=16). Subjects tracked s imple one- and two-dimensional motions at various frequencies. Perform ance was measured using an accuracy index derived from root-mean-squar e error, and a linearity index based on coherence estimation. A maximu m bandwidth of 2 Hz for accuracy of mouse use was found, which often d ecreased due to advanced age or motor disability. Tracking linearity o f 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 sh ow that with advanced age and disability, mouse use becomes increasing ly inaccurate and nonlinear. Assistive computer interfacing techniques , such as signal filtering, may improve mouse use.