The influence of auditory experience on the behavior of preterm newborns.

This review of the research literature is addressed to clinicians who care for, interact with, and advise parents of preterm newborns. In summary, research on the effects of sound on preterm infant behavior and development provide only a little reliable clinical guidance as many of the studies are flawed, some badly. Some studies use a high sound level (i.e., loud) stimulus yet fail to report effects of the stimulus on vital signs, movement, and behavioral state. Only a handful of studies report long term effects regardless of the length of exposure to the experimental stimulus. A consistent problem is that the ambient sound in the nursery research setting is neither described nor considered as a facet of the auditory stimulus yet all reports of ambient nursery sound show high levels without respite periods of quiet. Therefore, unless other documentation is provided, ambient nursery noise is likely an unreported confounding variable in these studies. The clinician is cautioned, therefore, to carefully evaluate any finding before implementing an intervention program of sound stimulation with preterm infants. There are many reports of efforts to reduce nursery noise by changing staff behavior but none describes more than marginal success. Given this general failure of noise reduction through behavior change, an alternative is proposed of achieving quiet by changing the crowded, reverberant nature of the physical space. Recommendations for care that can be drawn from this literature include measuring and reducing nursery noise, facilitating parents' efforts to talk and sing to their own babies, and limiting purposefully added sound stimulation to quite specific clinical situations.