Crognale M A, Page J W, Fuhrel A
Department of Psychology, University of Nevada, Reno 89557, USA.
Optom Vis Sci. 2001 Jun;78(6):442-6. doi: 10.1097/00006324-200106000-00018.
To examine changes in the chromatic onset visual evoked potential (VEP) as a function of aging.
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.
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.
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.
