In a recently released issue of Pediatrics(10.1542/peds.2019-0288), Dr. Renée Shellhaas and colleagues share with readers a fascinating study that examines the impact of maternal voice on the sleep of newborns receiving care in a level IV Neonatal Intensive Care Unit (NICU). In this study, 47 medically stable infants who were born at gestational ages 33-41 weeks and cared for in single-infant rooms underwent a 12 hour state-of-the-art polysomnogram sleep study: infants were randomized to hear a recording of their mother reading a children’s book during either the first or the second 6 hours of the sleep study. Standard sleep measures and an EEG (electroencephalogram) were recorded and scored, and a language processing device simultaneously audio recorded background noise – infants meanwhile continued to feed and sleep and receive routine care throughout. This study comes on the heels of recent work which the authors note suggests that infants protected from NICU noise in single rooms actually had abnormal language development as compared to those cared for in an open-bay and those with increased language exposure.1,2
The study yielded several interesting results. Measures of sleep, such as arousal metrics, were more strongly associated with gestational age at birth than the infant’s chronological age at the time of the sleep study; thus degree of prematurity impacted sleep-wake cycle development. In fact, for those infants of gestational age >35 weeks (but not those born at 33-34 weeks), increasing gestational age was associated with increasing awake time, but only during the voice recordings. And all infants were more likely to be able to stay asleep after loud noises during the voice recording, as compared to during usual care. The impact of the maternal voice recordings clearly reverberates throughout the study!
Ultimately, as the authors point out, more research is needed to understand when and how language exposure can best benefit the later language development of infants cared for in the NICU. This study suggests that the question is complex, in that optimal exposure may depend on gestational age at birth, chronological age at exposure, sleep-wake cycle, background noise, and other as yet unidentified factors. But at least for starters, I believe this study is wonderful news for parents. Rather than whispering and tip-toeing about the NICU, worrying that babies are being disturbed, this study suggests that mothers (and fathers, too!) can use every opportunity to “talk, read and sing” to their infants.3 Realizing that parental voice has a magic of its own is empowering knowledge.
References
1. Pineda RG, Neil J, Dierker D, et al. Alterations in brain structure and neurodevelopmental outcome in preterm infants hospitalized in different neonatal intensive care unit envrionments. Journal of Pediatrics. 2014;164(1):52-60.
2. Caskey M, Stephens B, Tucker R, Vohr B. Adult talk in the NICU with preterm infants and developmental outcomes. Pediatrics. 2014;133(3):e578-e584.
3. LoRe D, Ladner P, Suskind D. Talk, Read, Sing: Early Language Exposure As an Overlooked Social Determinant of Health. Pediatrics. 2018 Sep;142(3). pii: e20182007. doi: 10.1542/peds.2018-2007.
