Dementia in Parkinson's disease: the problem of clinicopathological correlation.

Four cases of Parkinson's disease with advanced dementia are described. Postmortem examination revealed cell loss in the substantia nigra, with Lewy bodies present, and loss of cells in the basal nucleus of Meynert. A few tangles were observed in the hippocampus, but no senile plaques or neurofibrillary tangles were found in the neocortex. The authors note that a dramatic dementia syndrome may occur with Parkinson's disease alone, without the associated cytoskeletal markers of Alzheimer's disease. Cases were characterized by disorientation, episodic confusion and hallucinations persisting off medication, disturbed behavior, and the absence of aphasia.