Premature infants, despite advances in NICU care, face significant risks to their physical and neurological development due to the stress of invasive procedures and assessments. These stressors can lead to physiological instability, potentially causing cerebral injury and long-term developmental issues. To mitigate these risks, neuroprotective strategies are vital.
Born too soon, premature infants leave the protective womb for the harsh, overwhelming environment of the NICU. Their underdeveloped systems struggle to cope with the constant barrage of bright lights, loud noises, and invasive touch. These infants endure frequent handling, often multiple times within a few hours, for essential assessments. Each interaction can trigger physiological stress, impacting vital functions. While eliminating all stressors is impossible, managing noise levels has emerged as a key focus for improving the NICU environment.
Sound, a vibration perceived by the auditory system, becomes relevant early in fetal development. By 20 weeks gestation, the structures are formed, including the crucial cochlea with its hair cells. These hair cells, essential for transmitting sound to the brain, are vulnerable to damage from environmental stressors like loud noise and certain medications, especially after the vestibular system becomes functional around 25-29 weeks. Background noise exceeding 60 decibels can significantly impair hair cell sensitivity.
Despite the American Academy of Pediatrics (AAP) recommending noise levels below 45 dB to protect infants' hearing in the NICU, the reality is far different. Typical NICU sound levels, often exceeding 50 dB, are exacerbated by medical equipment, alarms, and procedures. Even seemingly innocuous actions like opening incubator sleeves or closing portholes can generate noise levels far above the recommended threshold, putting infants at risk for hearing damage.
The unavoidable high noise levels inherent in premature infant care pose a significant risk to their auditory systems. These sounds, both sudden and excessive, can also disrupt vital physiological functions, leading to instability in heart rate, blood pressure, respiration, oxygen levels, and sleep patterns. Given that many NICUs already exceed the AAP's recommended noise limit of below 45 dB, the introduction of music therapy might seem paradoxical.