Auditory event-related potentials in Parkinson's disease in relation to cognitive ability.

Auditory event-related potentials were evaluated in 45 nondemented patients with mild to moderate Parkinson's disease and 40 matched normal controls. All patients were neuropsychologically assessed by means of the Raven Colored Progressive Matrices, four subtests of the Wechsler Memory Scale (Digit Span Forward, Logical Memory, Visual Memory, Associate Learning), and the Wisconsin Card-sorting Test. The P300 component of the auditory event-related potentials was significantly prolonged in the patients with Parkinson's disease. Correlations between P300 latency and neuropsychological measures showed significant associations with lower performance on the Raven Colored Progressive Matrices and the Wisconsin Card-sorting Test. Our results indicate that for patients with mild to moderate Parkinson's disease subtle changes in cognitive abilities may be reflected as P300 prolongation.