Effect of aging on sensorimotor functions of eye and hand movements.

Changes in coordinated eye and hand movements with aging were studied in normal young and elderly subjects. Electrooculograms, flexor and extensor electromyograms, and potentials representing hand movements were recorded and used to evaluate the performance in aiming tasks. The parameters that reflect motor functions did not change significantly with aging in both eye and hand movements. However, elderly subjects commonly showed increases in reaction times of the initial (open-loop) movements in both eye and hand movements. Interestingly, the time increments were almost equivalent in these two functionally distinct motor systems. The durations of error-correcting (closed-loop) movements also increased significantly with aging in both motor systems. These increases suggest that the aging effects are the manifestation of impairment in the sensory process.