The effect of sleep on motor learning in the aging and stroke population - a systematic review

There is extensive evidence for positive effects of sleep on motor learning in young individuals; however, the effects of sleep on motor learning in people with stroke and in healthy older individuals are not well understood. The aim of this systematic review was to quantify the association between sleep and procedural memory performance - a marker for motor learning - in healthy older people and people with stroke. After searches in PubMed, Medline and Embase fourteen studies, including 44 subjects after stroke and 339 healthy older participants were included. Overall, sleep was found to enhance motor performance in people after stroke in comparison to an equivalent time of wakefulness. In addition, although evidence is limited, sleep only enhanced motor performance in people after stroke and not in age-matched healthy older adults. In older adults the effect of a sleep intervention did - in general - not differ from equivalent periods of wakefulness. Tasks with whole hand or whole body movements could show significant changes. The results suggest a delayed retention effect after longer breaks including sleep, hinting towards a changed learning strategy as a result of aging. Current evidence for sleep dependent learning in people after stroke is promising, however sparse.