Dementia with Lewy Bodies and Parkinson's Disease-Dementia: Current Perspectives

Dementia with Lewy bodies (DLB) and Parkinson's disease-dementia (PDD) are two closely related major neurocognitive disorders with Lewy bodies of unknown etiology, showing notable overlap in their clinical presentation, pathological features, biochemistry, and genetic risk factors. According to international consensus, their diagnosis is based on an arbitrary distinction between the time of onset of motor and cognitive symptoms: dementia preceding parkinsonism in DLB, while it develops after onset of parkinsonism in PDD (the one-year rule). Clinically, both syndromes show cognitive impairment with severe deficits in executive function, visuo-spatial processing, fluctuating attention and parkinsonism, with higher prevalence of Alzheimer-type lesions in DLB that may account for earlier onset and severity of cognitive deficits.