EYE-MOVEMENTS IN PARKINSONIAN SYNDROMES

Eye movements were recorded in 14 patients with Parkinson's disease (P D) in the ''off'' condition, 14 patients with striatonigral degenerati on (SND), 10 patients with corticobasal degeneration (CBD), and 10 pat ients with progressive supranuclear palsy (PSP), with comparison with 12 control subjects. Vertical saccade paralysis was not observed in th e PD, SND, and CBD groups but was present in 9 patients of 10 in the P SP group. In the PD and SND groups, horizontal reflexive visually guid ed saccade latency and accuracy were similar, and differed only slight ly from those of controls. In the CBD group, saccade latency was signi ficantly increased and correlated to an ''apraxia score''; whereas, in the PSP group, saccade amplitude was significantly decreased. Thus, t he abnormalities of both horizontal saccade parameters in the PSP grou p contrasted with those observed in the CBD group. The percentage of e rrors in the antisaccade task, an index of prefrontal dysfunction, was markedly increased only in the PSP group. The smooth pursuit gain was decreased in all groups but more severely in the PSP group. It may be concluded that saccade abnormalities are clearly different in SND, CB D, and PSP, and might help in early differential diagnosis in individu al patients, but that SND cannot be differentiated from PD on the simp le basis of eye movement abnormalities.