Is the trackball a better input device for the older computer user?

This study investigated age-related differences in user performance and pre ferences 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 ol der adults took longer to complete movements than younger adults and did so to a greater extent for large amplitude movements, but that their movement s were less variable. There was no age difference in movement time or varia ble error between the two devices. It has been hypothesized that the findin gs 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 ,ed no age-related differences in muscle activity. Ratings of perceived ext ertion revealed that older adults reported higher levels of exertion than y ounger adults using the mouse during click-and-drag motions. In light of fi ndings demonstrating that older adults have lower strength, this finding im plies that the mouse requires a greater percentage of the elderlys' maximum force. These results taken together suggest that the trackball may be a be tter device for the elderly computer user especially when performing freque nt, repetitive actions for prolonged periods of time.