Light sleep and sleep time misperception – Relationship to alpha–delta sleep

ObjectiveWe investigated the association of alpha–delta sleep (A–DS) with: (1) perception of light sleep and (2) discrepancy between subjective and objective sleep duration.MethodsWe analyzed data from 5764 individuals who underwent polysomnography (PSG) and replied questions about quantity and quality of sleep, including sleep depth. The difference between objectively recorded sleep time and subjectively estimated sleep time was calculated. Alpha–delta sleep (A–DS) was visually scored in a scale from 1 to 4, based on the density and overnight duration of alpha activity and confirmed using spectral array of the electroencephalographic activity.ResultsA–DS scores 1–4 occurred in, respectively, 37.9%; 31.3%; 20.5%; and 6.2% of the cases. ANOVA showed significant difference of light sleep sensation (p < 0.001) and sleep time underestimation (p < 0.001) among the four A–DS categories. Regression to explain both light sleep and sleep time underestimation, controlling for confounders, confirmed A–DS as a significant regressor.ConclusionsThis study of a large prospective sample provides evidence for the association of alpha–delta sleep with subjective sensation of light sleep and with sleep time underestimation.SignificanceAlpha–delta sleep may be a marker of the physiological disorder underlying light sleep and sleep state misperception.