WEEKLY CHANGES IN PSYCHOPHYSIOLOGICAL VARIABLES OF 8-YEAR-OLD TO 10-YEAR-OLD SCHOOL GIRLS

Three groups of schoolgirls 8, 9, and 10 years of age, respectively, s elf assessed sleep onset/offset and duration, as well as oral temperat ure and a set of cognitive measures, at school at 09:00, 11:00, 14:00, and 16:00 h on Mondays, Tuesdays, Thursdays, and Fridays (and/or Satu rday) for 2 consecutive weeks (spring 1987 and 1989). The scores of a letter cancellation test exhibited neither daily nor weekly temporal v ariation at the age of 8 years [analysis of variance (ANOVA), p > 0.05 ]. In contrast, in the 10-year-olds, changes as a function of both tim e of day (peak time 14:00-1 6:00 h) and day of week (peak day Tuesday- Friday) were substantiated. Moreover, the time of best performance on the letter cancellation test varied systematically according to the da y of the week (ANOVA, p = 0.000). Day of the week changes in the obser ved duration of sleep, self-rated fatigue, drowsiness, and attention c hanges were not detected in any of the age groups. It is hypothesized that temporal performance variations in the girls during the 7-day per iod was age related.