ACHE and Alzheimer disease: Normal naïve listeners rapidly and spontaneously learn to understand sinewave messages.12 We hypothesized that compared with untreated healthy controls, AD patients in a relative cholinergic deficiency state (prior to the next dose of acetylcholinesterase inhibitor) would show impaired understanding of sinewave speech but that this would improve disproportionately to other cognitive functions following a dose of acetylcholinesterase inhibitor, given that sinewave speech perception is likely to depend on cognitive plasticity and dynamic neural processing.