ACHE and Alzheimer disease: Among these, one of the most extensively studied is the cholinergic system, with second-generation acetylcholinesterase inhibitors (AChEI), namely rivastigmine, galantamine, and donepezil, still representing the mainstay of therapy in AD, dementia with Lewy bodies (DLB), and Parkinson's disease dementia (PDD), and, although less widely accepted, even vascular dementia (VaD).