Color VEPs in Parkinson's disease.

Evoked potential studies have confirmed visual pathway impairment in Parkinson's disease. Dopamine is also known to be involved in retinal color vision mechanisms. In this study, pattern evoked potentials were recorded in 20 parkinsonian patients in "on" and "off" conditions to compare the sensitivity of black-and-white and color pattern stimuli. Evoked responses to colored patterns proved more sensitive to L-DOPA therapy. This finding supports the proposed dopamine modulation of the retinal color system and suggests that color pattern evoked potential studies might be used in monitoring dopamine therapy in parkinsonian patients.