This study will examine how well the study drug, BIIB092 works when compared to a placebo and to study the long-term safety and tolerability of the study drug in subjects with Progressive Supranuclear Palsy (PSP)
This study examines eye movements and the pupil's response to light in progressive supranuclear palsy (PSP), comparing to Parkinson's disease and control subjects without neurological disease. Computerized measures of eye movements and pupil changes will be used. Subjects will also receive an eye exam to rule out other eye diseases. The goal of this study is to use subtle changes in eye movements and the pupil's response to light for earlier diagnosis of PSP.