New Data on the Ontogeny of the Child's Sleep-Wake Rhythm

Abstract

The present study is part of a broader body of research concerning the ontogeny and regulations of the young child's sleep-wake rhythm. It was carried out with 12 children admitted to a day-care center from 4 or 5 months of age. None of the children showed any anomalies or functional disorders. The method used in this study consisted in organizing a data collection on the alternations of wakefulness and sleep as well as on the children's behavior throughout the 24-h period, both in their family and at the day-care center from 4 to 15 months of age. The main findings are (a) the circadian rhythm of wakefulness and sleep is clearly set up as early as at 4 months of age and consolidates between 6 and 7 months; (b) some ages are characterized by significant changes in the daily distribution and duration of sleep spans: 6 to 7 months; 10to 12months; 13to 15 months; (c) these changes suggest the existence of several ultradian rhythmicities which become successively prevailing from one age to the next throughout child development. The longitudinal study of the young child's sleep-wakefulness rhythm allows better evaluation of the influence of developmental factors in its structuralization and formulation of new hypotheses on its disorders and dysfunction. Individual factors are under study.

Key Words:

• Children
• Sleep-wake rhythm
• Circadian rhythm
• Ultradian rhythms
• Ontogeny
• Regulations
• Day-care centers