Neonatal Heart-Rate Response to Tactile, Auditory, and Vestibular Stimulation in Different States

Newborn cardiac activity was analyzed in the context of the orienting response. Stimuli in 3 modalities were presented to Ss in different states: before and after a feeding, while sleeping and awake. Each S received 3 trials of tactile, vestibular, and auditory stimulation. Statistical analyses were performed on heart rate (HR) during each of the 10 seconds of stimulation. In sleeping Ss, the HR response was primarily accelerative to tactile and vestibular stimulation but unreliable to auditory stimulation. For the awake Ss, the feeding variable affected Ss' responsivity to auditory and vestibular stimuli. Before feeding, awake Ss decelerated to both types of stimuli. After feeding, there was no reliable response to any stimulus. A decelerative response was also found to vestibular stimulation in sleeping babies tested before feeding, but only when this type of stimulus was presented first in the sequence. In general, newborns tended to respond with less variability when tested before feeding. The newborn's cardiac response to stimuli in different modalities is affected by arousal state and feeding condition.