Chapter 9 Dementia with Lewy Bodies and Parkinson's Disease Dementia

Abstract

Publisher Summary The chapter offers information on dementia with Lewy bodies and Parkinson's disease dementia. Neurodegeneration associated with abnormal alpha-synuclein metabolism and Lewy body (LB) formation may present as a variety of clinical syndromes depending on the distribution of pathologic changes and neurochemical disruption. Dementia with Lewy bodies (DLB) and Parkinson's disease (PD) are the two most commonly recognized manifestations of LB disease and the close association between them has only been recognized in the past decade. DLB is thought to account for up to 20% of all elderly cases of dementia reaching autopsy, with a clinical presentation primarily characterized by cognitive decline leading to dementia, accompanied in the majority of cases (∼75%) by extrapyramidal motor features and additional neuropsychiatric features. Parkinson's disease dementia (PDD) starts by contrast with extrapyramidal motor symptoms with the later onset of cognitive decline and psychiatric symptoms, progressing in many cases to a clinical and pathologic endpoint, which is largely indistinguishable from DLB. Distinction between DLB and PDD is based on the temporal sequence in which symptoms appear with the recommendation that PDD should be diagnosed if extrapyramidal motor features have been present for a year or more before cognitive decline is noted. Cholinesterase inhibitors (CHEIs) offer the greatest hope for symptomatic improvement in both psychotic and cognitive features of DLB and PDD at present and seem to offer these benefits without significant compromise of motor function.