Improving sleep and cognition by hypnotic suggestion in the elderly

Sleep quality markedly declines across the human lifespan. Particularly the amount of slow-wave sleep (SWS) decreases with age and this decrease is paralleled by a loss of cognitive functioning in the elderly. Here we show in healthy elderly females that the amount of SWS can be extended by a hypnotic suggestion “to sleep deeper” before sleep. In a placebo-controlled cross-over design, participants listened to hypnotic suggestions or a control tape before a midday nap while high density electroencephalography was recorded. After the hypnotic suggestion, we observed a 57% increase in SWS in females suggestible to hypnosis as compared to the control condition. Furthermore, left frontal slow-wave activity (SWA), characteristic for SWS, was significantly increased, followed by a significant improvement in prefrontal cognitive functioning after sleep. Our results suggest that hypnotic suggestions might be a successful alternative for widely-used sleep-enhancing medication to extend SWS and improve cognition in the elderly. [Display omitted] •Hypnotic suggestions increase the amount of deep sleep by 57% in the elderly.•Deeper sleep by hypnosis improves prefrontal cognitive functioning.•Well-controlled study using high density EEG recordings in the sleep laboratory.•Hypnosis might have the potential to benefit sleep and cognition in healthy aging.