Working memory and sleep in 6-to 13-year-old schoolchildren

Objective: To study the associations between sleep quality/quantity and performance in auditory/visual working memory tasks of different load levels. Method: Sixty schoolchildren aged 6 to 13 years from normal school classes voluntarily participated. Actigraphy measurement was done during a typical school week for 72 consecutive hours. It was timed together with the working memory experiments to obtain information on children's sleep during that period. The n-back task paradigm was used to examine auditory and visual working memory functions. Results: Lower sleep efficiency and longer sleep latency were associated with a higher percentage of incorrect responses in working memory tasks at all memory load levels (partial correlations, controlling for age, all p values <.05, except in visual 0-back and auditive 2-back tasks); shorter sleep duration was associated with performing tasks at the highest load level only (partial correlations, controlling for age, p <.05). Also in general linear models (controlling for age, gender, and socioeconomic status), sleep efficiency (F = 11.706, p =.050) and latency (F= 3.588, p =.034) were significantly associated with the mean incorrect response rate in auditory working memory tasks. Conclusions: Sleep quality and quantity affect performance of working memory tasks in school-age children. In children with learning difficulties the possibility of underlying sleep problems should be excluded.