Factors associated with vagal tone responses in preterm infants.

The purpose of this study was to examine factors related to vagal tone (VNA) among preterm infants receiving a 10-minute gentle human touch (GHT) intervention three times daily for 10 days. VNA was measured continuously for 10 minutes before, during, and after each 10-minute GHT intervention. Findings indicated that there was a significant relationship between VNA and gestational age, although there were no relationships between VNA and measures of motor activity or behavioral distress. There was no difference in pattern of response to GHT or level of morbidity, average daily weight gain, or behavioral organization among infants with low, moderate, and high baseline VNA levels. There was no difference in VNA comparing infants in the GHT and control groups or during baseline, touch, and posttouch phases for infants in the GHT group. There is a need for further research to examine the usefulness of VNA as a measure of stress vulnerability among preterm infants.