Longitudinal ocular motor study in corticobasal degeneration and progressive supranuclear palsy

Objective: To evaluate the usefulness of ocular motor information in the ea rly diagnosis of corticobasal degeneration (CBD) and progressive supranucle ar palsy (PSP). Methods: Seven PSP patients, six CBD patients, and three at ypical CBD patients were followed longitudinally with repeated electrooculo graphic (EOG) recordings, at 6-month intervals, to search for features that could confirm or modify the diagnosis. Visually guided saccades and antisa ccades were studied. Data from clinical evaluations were independently coll ected. Results: PSP patients had decreased saccade velocity throughout the disease course. Patients with probable CBD showed preserved saccade velocit y;but important increased saccade latency ipsilateral to the apraxia side. Similar to patients with PSP, those with atypical CBD features exhibited cl inically evident abnormalities of vertical saccades and early slowing of ho rizontal saccade velocity, but no increase in saccade latency or early squa re-wave jerks. When clinical "telltale signs" appeared and the clinical dia gnosis was reviewed independent of EOG recording, the three patients with a typical CBD features were diagnosed as having PSP although new or overlappi ng syndromes cannot be excluded. Conclusions: Consecutive EOG recordings he lp diagnose atypical CBD and PSP disorders earlier.