A detailed examination of the major neuropsychiatric syndromes of Parkinson's disease and a cognitive theory that accounts for their neurology and phenomenology. Patients with Parkinson's disease (PD) suffer most visibly with such motor deficits as tremor and rigidity and less obviously with a range of nonmotor symptoms, including autonomic dysfunction, mood disorders, and cognitive impairment. The neuropsychiatric disturbances of...