Is the Trackball a Better Input Device for the Older Computer User?

This study investigated age-related differences in user performance and preferences using two widely available computer pointing devices, a mouse and trackball. Participants acquired on-screen targets of varying distance and size using point-and-click and click-and-drag motions. It was found that older adults took longer to complete movements than younger adults and did so to a greater extent for large amplitude movements, but that their movements were less variable. There was no age difference in movement time or variable error between the two devices. It has been hypothesized that the findings reflected the adoption of a device independent movement strategy by the elderly designed to compensate for age-related declines in motor control. Analysis of muscle activity (RMS) of the forearm flexor and extensor showed no age-related differences in muscle activity. Ratings of perceived extertion revealed that older adults reported higher levels of exertion than younger adults using the mouse during click-and-drag motions. In light of findings demonstrating that older adults have lower strength, this finding implies that the mouse requires a greater percentage of the elderlys' maximum force. These results taken together suggest that the trackball may be a better device for the elderly computer user especially when performing frequent, repetitive actions for prolonged periods of time.