Measurement of cholinergic drug effects on memory in Alzheimer's disease.

Double-blind, placebo-controlled investigations of scopolamine, physostigmine, arecoline, and tetrahydroaminoacridine (THA) in normal adults and in dementia of the Alzheimer-type (DAT) were reviewed to determine the relative sensitivity of various assessment procedures in the measurement of drug effects. In normal adults, word list learning techniques have been most widely employed and have been sensitive to drug effects. In DAT, a wide variety of assessment procedures have been employed. Based on the limited number of possible comparisons across studies, two procedures appear to be useful: word list learning tasks that generate an index of intrusion errors, and visual recognition tasks. The lack of standardized assessments limits the ability of investigators to replicate studies, to compare relative efficacy of various drugs, or to address a number of other questions that are fundamental to the development of effective cholinergic treatments for DAT.