[Evaluation of intellectual functions in patients with Parkinson's disease. Bibliographic review].

A literature review shows that patients affected by Parkinson's disease present an intellectual impairment more frequently than the comparably aged population. Such impairment has been related to several factors (age, arteriosclerosis, motor difficulties, depression, dopaminergic therapy, cortical and/or subcortical lesions). Parkinsonian dementia may be caused by the extent of the degenerative process. Our own results show that parkinsonian patients with dementia are different from nondemented ones with the following features: a) a more marked bradykinesia b) a more severe extrapyramidal picture c) a progressive unresponsiveness to levodopa in a shorter time. It seems possible that there is a Parkinson syndrome characterized, clinically, by an intellectual impairment with a poor prognosis quoad valetudinem, and, anatomically, with multiple cortical and subcortical lesions. Such syndrome may be a "transition" form between Parkinson disease and senile-presenile dementia.