Aging of the chromatic onset visual evoked potential.

ABSTRACT

PURPOSE: To examine changes in the chromatic onset visual evoked potential (VEP) as a function of aging. METHODS: VEP's were measured in response to chromatic sinusoidal gratings (1.0 and 0.5 cpd), selectively chosen to modulate the L-M channel and S - (L+M) channel and presented in onset-offset mode. Responses to achromatic gratings presented in a reversal mode were also measured. Twenty subjects were tested, ranging in age from 21 to 93 years. RESULTS: Unlike changes observed earlier in life, the general shape of the chromatic onset wave-form changed little with age; however, latencies increased significantly as a function of age. Amplitude changes revealed a decreasing trend that was not statistically significant. There was little change in the achromatic responses with age. CONCLUSIONS: Our results demonstrate a systematic slowing of the chromatic onset VEP with age. The gradual nature of the latency changes and the lack of dramatic and complex wave-form shape changes may allow development of age-based normative data for use in clinical settings.