Dementia with Lewy bodies overlaps clinically with Alzheimer's disease and Parkinson's disease, but is more associated with the latter.With DLB, the loss of cholinergic (acetylcholine-producing) neurons is thought to account for the degradation of cognitive functioning, as in Alzheimer's disease; while the loss of dopaminergic (dopamine-producing) neurons is thought to account for the degradation of motor control, as in Parkinson's disease.
While the specific symptoms in a person with DLB will vary, core features of DLB are: 1) fluctuating cognition with great variations in attention and alertness from day to day and hour to hour 2) recurrent visual hallucinations (observed in 75% of people with DLB), and 3) motor features of Parkinson's. Suggestive symptoms are rapid eye movement(REM)-sleep behavior disorder and abnormalities detected in PET or SPECT scans.
Parkinson's features could include shuffling gait, reduced arm-swing during walking, blank expression (reduced range of facial expression), stiffness of movements, ratchet-like cogwheeling movements; low speech volume, sialorrhea and difficulty swallowing. Tremors are less common in DLB than in Parkinson's disease.DLB patients also often experience problems with orthostasis, including repeated falls, syncope (fainting), and transient loss of consciousness.One of the most critical and distinctive clinical features is hypersensitivity to neuroleptic and antiemetic medications that affect dopaminergic and cholinergic systems. In the worst cases, a patient treated with these drugs could become catatonic, lose cognitive function and/or develop life-threatening muscle rigidity.
There is no cure for DLB; available treatments offer relatively small symptomatic benefit but remain palliative in nature.