Cortical Lewy body disease and Parkinson's disease dementia

Abstract

The health and socioeconomic impacts of dementia with Lewy bodies and dementia associated with Parkinson's disease have become increasingly recognized. Whilst the nosological status of dementia with Lewy bodies has been better classified as 'Lewy body dementias', both conditions are now believed to represent a disease spectrum, characterized pathologically by synuclein protein and clinically by a variable admixture of cognitive, neuropsychiatric and extrapyramidal features. Recent epidemiological studies are described and clinical and pathological similarities emphasized between dementia with Lewy bodies and Parkinson's disease. A number of investigational techniques are highlighted which have helped to better characterize dementia with Lewy bodies and discriminate it from Alzheimer's disease, whilst also shedding light upon the pathophysiology of both conditions. Finally, the therapeutic aspects of the Lewy body dementias will be considered, concentrating upon studies of the cholinesterase inhibitors. The pathology underlying dementia with Lewy bodies and Parkinson's disease is heterogeneous, and is neither stereotyped in its topography nor its composition. Cholinesterase inhibitor drugs improve cognition and neuropsychiatric symptoms but the clinical response is unpredictable. Major future challenges are to better understand the pathophysiological basis underpinning the diseases, what determines clinical phenotypic expression and how disease-modifying therapies may best be developed and deployed.