Cerebral Cholinergic Activity Is Related to the Incidence of Visual Hallucinations in Senile Dementia of Lewy Body Type

Senile dementia of Lewy body type is characterized clinically by presenting symptoms such as acute/ subacute fluctuating confusion and in the majority also visual hallucinations, and neuropathologically by the presence of Lewy bodies especially in archicortical areas. Progressive dementia develops in the course of the disease which shares with Alzheimer''s disease a cortical cholinergic deficit, evident at autopsy. In two of four brain areas examined, parietal and temporal cortex, choline acetyltransferase activities were significantly lower in patients with, compared to those without, hallucinations (20% and 50% of the normal, respectively). These new findings suggest cholinergic mechanisms are involved in hallucinatory experiences and that this clinical feature may be diagnostic of severely deranged cholinergic activity in dementia.