Differences in sleep spindles and polysomnography in humans: a meta-analysis on the influence of age, sex, and cognitive ability

= 1,878 healthy subjects met our criteria. With age, sleep spindles decreased in amplitude, density, and duration. Sleep quality was reduced in older subjects showing shorter durations of both slow wave sleep (SWS) and rapid-eye movement (REM) sleep. Females revealed higher sleep spindle power (11-16 Hz), more prominent in older subjects; greater sleep efficiency, more total sleep time (TST), and longer SWS. Correlations between sleep properties and cognitive ability revealed age-dependent effects. Results yield key considerations in population comparisons and when targeting spindle activity, both for mechanistic research and for neuropsychiatric treatment. Yet further systematic investigations are warranted.