Diagnosis and management of parkinsonism in the elderly.

Of 123 patients with parkinsonism attending a department of medicine for the elderly who were assessed, 73% were thought to have idiopathic Parkinson's disease, and 91% of these cases and 52% of the remaining cases had a history of rest tremor; 34% of all cases were demented. The prevalence of dementia did not correlate with the duration of disease. Demented patients with presumed idiopathic Parkinson's disease were not distinguishable from non-demented by duration of disease, presence of a history of rest tremor or use of L-dopa. Eighty-eight per cent of non-demented patients but only 44% of demented patients were thought to have responded to L-dopa. Lower doses of L-dopa were used than are conventional with younger patients.