Normal checkerboard pattern reversal evoked potentials in parkinsonism.

The utility of checkerboard pattern reversal visual evoked potentials in the evaluation of Parkinson disease (Pd) was studied in 25 patients and controls without eye pathology. The results did not reveal differences in potential latency but the amplitude appeared slightly larger in PD than controls. Major intraocular differences were observed only in Pd patients with glaucoma, cataracts or retinal degeneration. The commonly employed high contrast and luminance, checkerboard pattern reversal technique did not appear useful in the evaluation of Pd. Selection of proper stimulus parameters may be critical in detecting VEP abnormality in Pd.