Short sleep duration is associated with poor performance on IQ measures in healthy school-age children

Objective: To examine the associations between habitual sleep duration and intellectual functioning in healthy, well-rested, school-age children. Methods: The study group consisted of 39 healthy children, aged 7-11 years old. Nightly actigraphic sleep recordings were taken for four consecutive nights to determine habitual week-night sleep duration in the home environment. Objective measures of cognitive functioning and sleepiness were used to measure daytime functioning. Results: Longer habitual sleep duration in healthy school-age participants was associated with better performance on measures of perceptual reasoning and overall IQ, as measured by the WISC-IV, and on reported measures of competence and academic performance. No association between sleep duration and the studied behavioral measures was found. Conclusions: These findings support the hypothesis that sleep duration is differentially related to some components of cognitive functioning, even in the absence of evidence for sleep deprivation or attention deficits. (C) 2010 Elsevier B.V. All rights reserved.