Distribution of skin potential responses according to states of sleep during the first months of life in human babies

Abstract

Sixty polygraphic records were made: 16 in newborns and 44 in infants aged from 1 to 25 weeks. 1. 1. The stage of development of the central nervous system is better defined by criteria such as spindle maturation or skin potential response (SPR) distribution according to stages of sleep, than by chronological age; SPR prevalence during “quiet” sleep (“adult” distribution) is not apparent before 12 weeks of age. Classification according to the presence or absence of spindles during quiet sleep shows that: (a) in the group without spindles (1–6 weeks old), SPRs are more numerous during “active” sleep than in newborns; (b) in the group with sporadic spindles (3–11 weeks old) the SPR mean frequency is about the same in “active” and in “quiet” sleep; (c) SPR prevalence during “quiet” NREM sleep (“adult” distribution) appears clearly in the group with spindles present throughout “quiet” sleep (10–25 weeks old). On the contrary, no relation was found between SPR distribution and the mode of onset of sleep. 2. 2. “Active” REM sleep seems to mature earlier than “quiet” NREM sleep. Our studies show that, in active sleep, SPRs increase significantly during the 1st month of life; after that, their frequency does not change any more. On the contrary, SPRs in quiet sleep increase throughout the whole period studied. This increase is also parallel to sleep spindle maturation. 3. 3. During transitional periods SPR frequency is between that of active and that of quiet sleep. There is no significant difference between SPR frequency during the first and the second sleep cycles.