Effect of aging on saccadic eye movements to visual and auditory targets

Elderly patients with diseases of the central nervous system often show saccadic disorders. Before these disorders can be called pathological, they must be distinguished from the physiological effects of aging. The purpose of this study was to determine the effect of aging on visual and auditory saccadic eye movements. Ninety healthy volunteers were divided into three groups (younger than 30 years; 30-50 years; older than 50 years), with 30 volunteers in each group. Visual and auditory predictive 15-degree saccades were evoked and recorded with electrooculography. Recorded parameters were peak velocity, duration, and latency. Both stimuli showed increasing latencies with increasing age and a higher peak velocity in the middle group as compared to the oldest group. The latter result was significant only for saccades to visual targets. Duration was almost identical for both patterns and all age groups. Between the age groups, latencies were significantly shorter for the saccades to auditory targets, and no differences in peak velocity occurred. The results stress the importance of an age-related assessment for saccadic parameters. The increasing latency and decreasing peak velocity in elderly people probably result from age-related degenerative changes in central nervous system parts that are involved in the generation of saccadic eye movements. We found no indications of a different effect of aging through either the visual or the auditory pathway for saccadic parameters.