Neonatal intensive care unit incubators reduce language and noise levels more than the womb

Objective: To assess the sound reducing characteristics of modern incubators in the neonatal intensive care unit (NICU) and to better characterize auditory and language exposures for NICU infants. Study design: Sound frequency spectral analysis was conducted on language and noise audio acquired simultaneously inside and outside incubators located in the NICU. Results: Sound transmission into the incubators was nonuniform. Very low-frequency sounds (<100 Hz) were unattenuated or even slightly amplified inside the incubators. Maximal reduction was observed for low-to-mid frequencies (300–600 Hz) and high frequencies (>2000 Hz), which convey important language information. Conclusions: Sound reductions observed across NICU incubator walls are more severe than those reported for sound transmission into the intrauterine environment, particularly for midrange frequencies that are important for language. Although incubator walls may serve as a protection against noxious noise levels, these findings reveal a potentially detrimental effect on language exposure for infants inside a NICU incubator.