Vagal Regulation of Heart Rate in the Prediction of Developmental Outcome for Very Low Birth Weight Preterm Infants

To Investigate heart rate and respiratory sinus arrhythmia (RSA) as markers of developmental outcome, infant ECG and 3 year outcome were assessed in 41 very low birth weight (<1,500 g) infants. Measures of mean hart rate and RSA, and the maturational shifts in their values from 33 to 35 weeks gestational age, were recorded. RSA measures predicted 3 year outcome beyond the effects of birth weight, medical risk, and socio-economic status. Higher RSA was associated with better social skills, whereas greater RSA maturation was associated with better mental processing and gross motor skills. Lower heat rate was associated with better behavior regulation and social skills, whereas greater maturational decreases were associated with better gross motor skills. Dividing the sample into groups of infants with birth weight less than 1,000 g and these with birth weight over 1,000 g, RSE maturation emerged a strong predictor of mental processing, knowledge base and gross motor skills in the former. A measured of joint maturation of RSA and heart rate was associated with better behavior regulation at 3 years, as measured by Child Behavior Checklist and parenting Stress Index scores, for this group. The findings directly respond to the need for physiological variables in the prediction of outcome in high-risk infants.