Idiosyncratic cardiovascular response of human neonates to acoustic stimuli.

The heart rate response of acoustic stimuli was assssed for 15 newborns between the ages of 24 and 48 hr. Results of the analyses of covariance demonstrated that although the subjects responded to the stimuli, their responses were idiosyncratic in magnitude, direction, and pattern of rate change. Although spectrum and duration of the stimuli were varied, they were found not to be significant sources of response variation.