Visual event-related potentials in progressive supranuclear palsy, corticobasal degeneration, striatonigral degeneration, and Parkinson's disease

To determine whether there are characteristic changes in event-related pote ntials (ERPs) in parkinsonian syndromes we studied 8 patients with progress ive supranuclear palsy (PSP), 10 patients with corticobasal degeneration (C BD), 9 patients with striatonigral degeneration (SND), and 16 patients with idiopathic Parkinson's disease (PD) with a mean duration of illness shorte r than 5 years in each group. A visual oddball paradigm was employed to eli cit P300. P300 to the rare target and rare nontarget stimuli and reaction t ime (RT) to rare target stimuli in each group were compared with those in t he corresponding age-matched normal control group and to each other after a ge correction. The correlation of P300 and RT to motor disability score was also studied. In PSP P300 amplitude was markedly reduced while in CBD P300 latency was prolonged P300 amplitude to rare nontargets in SND and PD was attenuated. The mean RT in the PSP and the CBD group was significantly long er than in the other two groups. The mean RT in PD and P300 amplitude to ra re nontargets in both CBD and PD showed significant correlation with the se verity of motor disability. Simultaneous measurement of P300 and RT may yie ld useful supplementary information in facilitating diagnosis of parkinsoni an syndromes in addition to clinical criteria.