Delayed Onset of Sleep-Wake Cycling with Favorable Outcome in Hypothermic-Treated Neonates with Encephalopathy

ObjectiveTo determine whether hypothermia modulates acquisition of sleep-wake cycling in term neonates with moderate to severe hypoxic-ischemic encephalopathy (HIE) and the relationship to outcome.Study designTwenty-nine term infants with moderate to severe HIE treated with selective head cooling were evaluated. All were monitored with amplitude-integrated electroencephalography during and video electroencephalography immediately after hypothermia for ≥72 hours. Electroencephalograpic data were analyzed for background and sleep-wake cycling. Abnormal outcome included death or severe global neurodevelopmental disability ≥18 months.ResultsAcquisition of sleep-wake cycling was noted in nine infants by 72 hours, in 13 by 96 hours, 19 by 120 hours, and 22 by 144 hours. Presence of sleep-wake cycling was associated with normal outcome, that is, 14 of 22 (64%), versus abnormal outcome, that is, none of seven without sleep-wake cycling (P = .006). The presence of sleep-wake cycling by 120 hours had a positive predictive value of 68% and negative predictive value of 90%. Magnetic resonance imaging abnormalities were related to onset of sleep-wake cycling.ConclusionsAlthough onset of sleep-wake cycling is markedly delayed in term neonates with moderate to severe HIE treated with hypothermia, approximately 65% with acquisition of cycling have a normal outcome. Sleep-wake cycling is an important additional tool for assessing recovery in term infants with moderate to severe HIE treated with hypothermia.