Schooltime subjective sleepiness and performance in Italian primary school children

Despite its clinical importance, the issue of the diurnal time course of sleepiness and performance in children remains largely unexplored. The objective of this study is to draw a profile of daytime subjective sleepiness and performance, at simple and complex tasks, in a cohort of Italian primary school children. To this aim, a sample of 316 children (age range: 5-11 years; mean 8.2 +1.5) was recruited and sub-divided into 3 groups, according to age: Group 1 (5-7 years; N= 127), Group 2 (8-9 years; N=108), Group 3 (10-11 years; N=81). Subjective sleepiness and simple performance were evaluated respectively through the Pictorial Sleepiness Scale and the Simple Reaction Time Task. Executive functions were addressed by means of the “Go/No Go” Task. Measurements were made in the children’s class three times a day, one day a week over a three weeks period in order to reliably reflect the habitual time course of sleepiness and performance, within the following time intervals: a) 8:30 am-10:30 am; b) 11 am-1 pm; c) 2 pm-4 pm. For the global sample, a significant increase of subjective sleepiness was found at the end of school day (2-4 pm), although at relatively low levels. No significant differences were observed in reaction times across the day, whereas a significant worsening was detected in performance at complex task already since mid morning. Significant correlations were found between subjective sleepiness and complex performance at all points. Slight age-related differences were found in the time courses of subjective sleepiness: in fact, a significant overday reduction of vigilance levels, from mid-morning onwards, was observed in children aged 5-9 years, but not in the older children (10-11 years). However, the daily time course of both simple and complex performance did not differ between children of the three age groups. Our results show changes in vigilance and cognitive functions across a typical schoolday in childhood, as well as age-related differences in sleepiness profile, that we suggest to thoroughly consider when conceiving chronopsychological interventions in the school context.