Reducing NICU noise improves wellbeing of infants

Neonatal intensive care units can be noisy places which can disturb the sleep patterns of the youngest patients in the hospitals and have a negative effect on their health. In an effort to ameliorate this, some NICUs have set quiet times to limit exposure to noise. However, little was known about the effects of the ‘quiet time’ on infant health and it is only now according to a recent study in The Journal of the Acoustical Society of America that researchers have demonstrated its beneficial effect. The study, one of the first in this field, examined the effects of quiet time implementation in multiple NICUs on infants up to 18 months after implementation. They analysed how each NICU’s soundscape changed throughout the day and how this affected infant heart rates. They found that certain stressful pitches were actually quieter in respect to their effect on infant heart rates and that very loud sounds occurred less frequently with the result that quiet time throughout the day was longer. The results provide a sense of which features of quiet time policies have the largest impact on infants in NICUs and they recommend using quiet time protocols to help NICU patients in addition to implementing architectural noise reduction strategies in NICUs.
In a separate, but related study published in Sleep last year, researchers showed that preterm newborns sleep better in NICUs while hearing their mother’s voice. The study explored the possibility that infants’ exposure to their mother’s voice in the NICU could modulate the impact of noise in the NICU. The results indicate that newborns in a NICU were less likely to be awakened by noises when a recording of their mother’s voice was playing. The study also found that newborns born at or after 35 weeks’ gestation show sleep-wake patterns that appear to respond increasingly with age to recorded maternal voice exposure. Similar associations were not found for infants born before 35 weeks’ gestation. It appears that exposure to a mother’s voice recording may insulate NICU patients from some of the impact of unavoidable noise by reducing the likelihood of wakefulness during the highest peak noise levels. Because of this, the researchers suggest that for infants who are ill or born prematurely and may require extended care in a NICU during a time of critical brain development, interventions designed to improve sleep may need to be tailored according to gestational age. As such, the impact of playing a recording of a mother’s voice, reading a story for example, may have a more significant impact for newborns who are near term gestation than for more premature infants.