BODY MOVEMENTS DURING SLEEP - MATURATION DURING THE FIRST 6 MONTHS OFLIFE

This work analysed the evolution of generalized motility from normal b irth (39 to 40 weeks of gestational age) to six months of age, in 73 h ealthy infants during sleep, according to age. Sleep polygraphic recor dings were performed in the morning; body movements were recorded with piezo-electric accelerometers. Our results showed that the number of movements per sleep hour was higher in active sleep (AS) as compared t o quiet sleep (QS) whatever the age although the difference was less i mportant in neonates (P < 0.05) than after one month of life (P < 0.00 1). The number of movements and the percentage of lime spent in moveme nts decreased with age; however in BS these parameters decreased sharp ly from birth to one month and a half but then did not significantly d iffer; in AS they became progressively lower: There were no statistica lly significant differences in the duration of body movements between sleep states in each age group; their mean duration became shorter fro m birth to six months of age (in AS P < 0.0001 and in QS P < 0.05). Th e distributions of the number of movements throughout the sleep stage were different according to sleep state and age. The movements were eq ually distributed during AS whatever the age and in the neonate group during QS; in older infants, the number of movements increased at the beginning and at the end of QS stages. During the first six months of life, spontaneous motility during sleep was inhibited, however this pr ocess differed in quiet and active sleep. The relationship between bod y movements and sleep stages' organisation became closer during matura tion.