PSP is one of the parkinsonism-plus syndromes. Like Parkinson's disease, the dopamine system is affected, but in addition cholonergic and adrenergic systems are affected. Some of the symptoms of PD are present, although tremor is unusual and postural instability is often a major problem. Eye movements are often impaired. There is a poor response to medication.
Progressive Supranuclear Palsy
What is PSP?