The Effects of Donepezil on Postlearning Sleep EEG of Healthy Older Adults

Introduction: Aging is associated with cholinergic hypofunction and memory decline. Cholinergic activity also plays a crucial role in sleep-dependent memory consolidation. The acetylcholinesterase inhibitor (ACNE-I) donepezil has been found to increase sleep-related procedural memory consolidation in healthy older adults in a previous study. Methods: Data of the former study were reanalyzed with regard to the effects of donepezil on the sleep EEG of healthy older adults. This analysis was conducted with a special focus on spectral parameters of sleep, which have previously been linked to plasticity-related processes during sleep, i.e., sigma and delta activity. Fortytwo participants (aged: 60-77 years) received 5 mg of the ACNE-I donepezil orally 30 min before bedtime in a placebo-controlled, double-blind design. Power values for EEG delta, theta, alphal, alpha 2, sigma, beta and gamma frequency bands were calculated for stage 2 NREM sleep, SWS and REM sleep. Results: In line with our hypotheses, the AChEI donepezil led to an increase in sigma activity during stage 2 NREM sleep and delta activity during slow wave sleep. Conclusion: These results suggest that an ACNE-I facilitates processes of sleep-dependent memory consolidation in older adults.