Longitudinal ocular motor study in corticobasal degeneration and progressive supranuclear palsy

To evaluate the usefulness of ocular motor information in the early diagnosis of corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). Seven PSP patients, six CBD patients, and three atypical CBD patients were followed longitudinally with repeated electrooculographic (EOG) recordings, at 6-month intervals, to search for features that could confirm or modify the diagnosis. Visually guided saccades and antisaccades were studied. Data from clinical evaluations were independently collected. PSP patients had decreased saccade velocity throughout the disease course. Patients with probable CBD showed preserved saccade velocity but important increased saccade latency ipsilateral to the apraxia side. Similar to patients with PSP, those with atypical CBD features exhibited clinically evident abnormalities of vertical saccades and early slowing of horizontal saccade velocity, but no increase in saccade latency or early square-wave jerks. When clinical "telltale signs" appeared and the clinical diagnosis was reviewed independent of EOG recording, the three patients with atypical CBD features were diagnosed as having PSP although new or overlapping syndromes cannot be excluded. Consecutive EOG recordings help diagnose atypical CBD and PSP disorders earlier.