Differences and similarities between Lewy body dementia and Parkinson's disease dementia

The diagnosis of Lewy body dementia (LBD) and Parkinson's disease dementia (PDD) is based on an arbitrary distinction between the time of onset of cognitive and motor symptoms. Both diagnoses share many features, like the presence of Lewy bodies, the core symptomatology and the core neurochemical deficits. However, the cognitive symptoms are more severe in DLB, very likely due to extensive beta-amyloid deposits in the cortex, the parkinsonian symptoms are more severe in PDD, due to the more extensive loss of presynaptic dopaminergic neurons and the hippocampal atrophy is more extensive in DLB, very likely due to a loss of fronto-hippocampal projections. Therefore DLB and PDD seem to be part of a spectrum of Lewy body pathologies, which may be accompanied by other protein deposits, like beta-amyloid, causing a different seventy and timing of the symptoms. The cognitive symptoms and hallucinations can be treated by cholinesterase inhibitors and anti-psychotics. DLB patients mostly do not tolerate antipsychotics, causing extrapiramidal side effects