Movement specification time with age.

An experiment is reported which localizes and compares movement specification times between three age groups, young (18-25 yrs.), middle (40-50 yrs.), and elderly (65-75 yrs.), in order to assess whether movement planning processes are partially responsible for the commonly observed slowing of response initiation time in the elderly. A movement precuing paradigm was used in which 24 subjects (8/age group) received either no, partial, or complete movement task information prior to the imperative response signal. The results established that the elderly had slower reaction times, movement times, information transmission rates and more errors. While the results indicated that the elderly could use precue information to prepare an upcoming movement, their specification times for arm, direction, and extent were markedly slower. The data are interpreted as providing evidence that part of the slowing in reaction time observed in the elderly is due to the increased time required to specify a dimension of movement.