Parkinson’s Disease and Dementia with Lewy Bodies

Abstract

Parkinson’s disease (PD), PD with dementia (PDD), and dementia with Lewy bodies (DLB) can all be seen as falling within the spectrum of diseases known as Lewy body disease, which is characterized by the presence of Lewy bodies. Parkinsonism in DLB shows less resting tremor and fewer bilateral differences than that in PDD. On the other hand, cognitive dysfunction, such as in processing speed, visuospatial cognition, executive function, and attention are more pronounced in DLB than in PD. Dementia with Lewy bodies is also characterized by more Alzheimer pathology than PDD. Neuronal loss of the substantia nigra is greater in PDD than in DLB. In general, the term DLB is used when dementia precedes Parkinsonism, while PDD is used when Parkinsonism precedes dementia by more than one year. There is no evidence, however, to support a fundamental difference between the two.