Do former preterm infants remember and respond to neonatal intensive care unit noise?
BACKGROUND
Previous studies have shown that 4-month-old infants have a decrease in heart rate, a component of the orienting reflex, in response to interesting auditory stimuli and an increase in heart rate to aversive auditory stimuli.


OBJECTIVE
To compare the heart rate responses of former preterm and term infants at 4-5 months corrected age to a recording of NICU noises.


METHODS
13 former preterm infants and 17 full-term infants were presented NICU noise and another noise of similar level and frequency content in random order. Heart rate 10s prior to the stimulus and for 20s during the stimulus was analyzed. Group differences in second by second heart rate changes in response to the two noise stimuli were compared by analysis of covariance.


RESULTS
Both the preterm and term newborns responded similarly to the NICU noise and the control noise. The preterm infants did not alter their heart rate in response to either stimulus. In contrast, the term infants displayed an orienting response to the second stimulus presented regardless of whether it was the NICU or control noise.


CONCLUSIONS
Former preterm infants at 4-5 months corrected age have reduced responsiveness to auditory stimulation in comparison to 4- to 5-month-old term infants. Furthermore, they did not respond to the NICU noise as an aversive stimulus.
Barreto
Edwin D
ED
Department of Pediatrics, Division of Perinatal-Neonatal Medicine, University of Texas Medical School at Houston, TX 77030, USA.
Morris
Brenda H
BH
Philbin
M Kathleen
MK
Gray
Lincoln C
LC
Lasky
Robert E
RE
D000161:Acoustic Stimulation; D016022:Case-Control Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000523:psychology*; D007363:Intensive Care Units, Neonatal; D008297:Male; D009622:Noise; D012016:Reference Values