This Publication Is Searchable The Merck Manual of Diagnosis and Therapy Section 14. Neurologic Disorders Chapter 179.
Etiology is unknown.
Neurons in the basal ganglia and the brain stem degenerate. Typical pathologic changes include neurofibrillary tangles containing an abnormally phosphorylated tau protein. Symptoms usually begin in late middle age. The oculomotor disturbance often begins with abnormal vertical gaze. Patients have trouble climbing up and down stairs or looking up without neck extension.