Visual evoked potentials in Parkinson's disease - correlation with clinical involvement

A total of 18 patients with Parkinson's disease were evaluated clinically a nd by transient checker-board VEP study. There were significant differences between bradykinesia (P < 0.01), rigidity (P < 0.02), and tremor (P < 0.05 ) subscores of the more and less severely affected sides. There were no asy mmetry of VEP latency or amplitude between the more and less severely affec ted sides by stimulation of the corresponding eye. There were no significan t correlations between the VEP latency or amplitude and any of the clinical features except the bradykinesia scores. The bradykinesia scores on the mo re severely involved side (r: 0.57; P = 0.014) and less severely involved s ide (r: 0.82, P = 0.00003) showed medium to high degree positive correlatio ns with VEP amplitudes by stimulation of the corresponding eye. By studying monocular fullfield responses our data can only suggest that there is no p rechiasmal asymmetry. The positive correlation between the VEP amplitude an d bradykinesia score might indicate that D2 receptors dominate in the retin a. (C) 2001 Elsevier Science B.V. All rights reserved.