Dementia with Lewy bodies (DLB) is defined, and differentiated from Parkinson’s Disease Dementia, as the emergence of dementia prior to, or within one-year of onset of Parkinsonism (movement symptoms). For unclear reasons, the onset of dementia and cognitive symptoms can vary greatly in synucleinopathies, with some patients living with Parkinson’s Disease for over ten years before developing dementia (PDD) and others having dementia prior to the onset of motor symptoms (DLB). Furthermore, at autopsy patients with PDD and DLB can have very similar findings of Lewy bodies throughout the brain, in addition to varying degrees of Alzheimer’s disease–associated plaque and tangles.
Clinical symptoms of DLB are identical to PDD in most cases, and in addition to motor difficulties (i.e. tremor, rigidity, falls, ect.), they have prominent cognitive features of:
Treatment includes medications used in Alzheimer’s disease to boost the neurotransmitter acetylcholine; however, there are currently no available treatments that prevent the neurodegenerative process (disease-modifying therapies).
The reasons for the different timing of dementia despite similar clinical features and pathological findings are unclear but are a matter of intense research. The Penn FTD Center and our colleagues at the Penn Udall Center for Excellence in Parkinson’s Disease Research are working on biomarkers to better distinguish DLB patients from PDD and other neurodegenerative diseases and help understand the relationships between Lewy pathology and Alzheimer’s disease-associated plaques and tangles to develop disease-modifying treatments.