Early and widespread cholinergic losses differentiate dementia with Lewy bodies from Alzheimer disease.

Background: Reductions in cholinergic function occur in Alzheimer disease (AD) and dementia with Lewy bodies and correlate with cognitive decline. However, whether such alterations appear in early-stage disease is unclear.

Objective: To examine the timing of cholinergic deficits in AD and dementia with Lewy bodies.