Mutual interference between a visual and a motor task in young and elderly subjects

Abstract

Since aging brings about difficulty in dividing attention, this study aimed at verifying, in youth and aged: (1) the possible interference between a visual and a motor task; (2) whether such interference varies between young and elderly subjects; (3) whether there is correlation between the proposed tasks and the trail making test (TMT) and the timed up-and-go test (TUGT). The visual task measured the ability to state whether two quickly presented figures were same or different. The motor task consisted on alternating steps from the ground to a 10 cm-high platform. Tasks were assessed both as single-task (isolated) and dual-task (simultaneous) in two groups: 10 young people (aged 23±2.8) and 10 elderly (aged 68.8±8.6). In the visual task, young volunteers presented less errors than the elderly (p<0.001); in both groups no increase in the number of errors was detected at dual-task when compared to the single-task. At the motor task the elderly presented lower speed in dual-task as compared to the single-task (p=0.009). TMT correlated positively to the number of alternations of step (p<0.05) and TUGT correlated negatively to the number of alternations of step (p<0.05). For both young and elderly, the motor task did not interfere on the visual task; however, the elderly showed lesser speed in the motor task when associated to the visual task. The non-assignment of primality to either task proved useful to detect these interferences.