Neuropsychological follow-up of parkinsonian patients with and without cognitive impairment.

In order to evaluate possible progression in the severity of their cognitive impairment, 34 parkinsonians with intellectual impairment were followed longitudinally for 7 years. Each patient was matched for age, sex, severity and duration of illness, and pharmacological treatment, with a parkinsonian patient without cognitive impairment. Results suggest that cognitive deficits are not static but rather there is a progression in the severity. Furthermore, patients suffering from severe dementia are more likely to die during the follow-up period. The prognosis of Parkinson's disease seems to be changed substantially by the occurrence of dementia. The natural history of parkinsonian dementia does not seem to differ from the history of other forms of dementia with a progressively disabling course leading to a complete loss of autonomy.