Clinicopathologic Study of Dementia in Parkinson Disease

We attempted to correlate dementia to histopathologic lesions in 15 autopsy patients with Lewy body type Parkinson disease (PD) by semiquantitative analysis of Alzheimer pathology, cortical Lewy bodies, locus ceruleus, nucleus basalis and vascular lesions. Ten out of the 15 patients were demented and consisted of 6 with PD alone, 2 with PD and marked Alzheimer pathology, 1 with PD, marked Alzheimer pathology and diffuse Lewy body disease and 1 with multiple cerebral infarcts, PD and marked Alzheimer pathology. The degeneration of the locus ceruleus was prominent in 2 patients with marked dementia but without any significant cortical pathology. Our findings are consistent with previous observations suggesting that the cause of dementia in PD is heterogeneous and further indicate that degeneration of the locus ceruleus may contribute to the pathogenesis of dementia in a subgroup of PD patients.