Neurophysiologic assessment of neonatal sleep organization: preliminary results of a randomized, controlled trial of skin contact with preterm infants.

BACKGROUND Sleep is important to brain organization, but few strategies to promote sleep among premature infants have been tested. Behaviorally based measures of sleep have shown increased quiet sleep (QS) and decreased active sleep (AS) during skin-to-skin contact (SSC) with the mother, but these results have not been confirmed with objective electroencephalographic/polysomnographic measures of sleep organization. Important differences exist between behavioral and electroencephalographic/polysomnographic definitions of sleep state. METHODS Data for the first 28 relatively healthy, preterm subjects of an ongoing randomized trial of one 2- to 3-hour session of SSC or incubator care between feedings are reported here. Infants were positioned prone, inclined, and nested in an incubator during the 2- to 3-hour pretest period, were fed, and then went into the test period of SSC or incubator care. Infants were left largely undisturbed throughout testing. A mixed-model regression analysis compared the test-pretest differences in outcome measures within and between groups. RESULTS Results showed that arousals were significantly lower in the SSC group, compared with the control group, for the entire study period and for test-pretest matched segments of QS and AS. Rapid eye movement was significantly lower for the SSC group for the study period and AS segments. Indeterminate sleep was significantly lower for the SSC group when confounding environmental variables were included in the regression analysis. When 4 subjects who experienced excessive ambient light levels during SSC were removed from analysis, QS increased during SSC. CONCLUSIONS The patterns demonstrated by the SSC group are analogous to more-mature sleep organization. SSC may be used as an intervention to improve sleep organization in this population of preterm infants.