Time-of-day effects on postural control and attentional capacities in children

Abstract

The present study aimed to examine the effect of time-of-day on postural control, body temperature, and attentional capacities in 5–6year old children. Twelve male children (5–6-year-old) were asked to maintain an upright bipedal stance on a force platform with eyes open (EO) and eyes closed (EC) at 07:00, 10:00, 14:00, and 18:00h. Postural control was evaluated by center of pressure (CoP) surface area (CoPArea), CoP mean velocity (CoPVm), length of the CoP displacement as a function of the surface (LFS) ratio and Romberg's index (RI). Oral temperature and the simple reaction time were also recorded at the beginning of each test session. The one way ANOVA (4time-of-day) showed significant time-of-day effects on CoPArea (p<0.001), CoPVm (p<0.01), LFS ratio (p<0.001) and RI (p<0.01). Children's postural control was lower at 07:00h and at 14:00h in comparison with 10:00h and 18:00h. Likewise, the reaction time was significantly (p<0.001) better at 10:00h and 18:00h in comparison with 07:00h and 14:00h. Oral temperature was higher at 14:00h and 18:00h than 08:00h and 10:00h (p<0.001). In conclusion, the children's postural control fluctuates during the daytime (i.e., better postural control at 10:00h and at 18:00h) with a diurnal rhythm close to that of body temperature and attentional capacities. Therefore, the evaluation of changes in postural control of 5–6-year-old children using force plate measures is recommended in the middle morning or the late afternoon to avoid the post-awakening and the post-prandial phases.