Respiratory sinus arrhythmia and social interaction patterns in preterm newborns

Recent evidence suggests that the amplitude of respiratory sinus arrhythmia (RSA) may be a useful predictor of cognitive and affective development in high-risk infants. Stability and relations among RSA and behavioral measures were studied in healthy and sick (respiratory and/or central nervous system disorders) preterm newborns at approximately 35 and 42 weeks postconceptional age (PCA). The Hobel Neonatal Complications Factor score was used to measure the extent of neonatal illnesses potentially associated with subsequent developmental risk. At each age, an electrocardiogram (ECG) was recorded for 10 min each during active sleep and social interaction. The amplitude of RSA was derived from ECG using the Porges (1986) method to estimate cardiac vagal tone (V). The study examined the relationship between neonatal RSA and simultaneous videotaped recordings of infants' focused attention, unfocused alertness, and distressed/avoidant behavior under two conditions: (a) during a standardized protocol for responsive social interaction with an examiner at 35 and 42 weeks; and (b) during an unstructured interaction session with their mothers at 42 weeks. At 35 weeks, RSA was related to neonatal behavior with an examiner. In addition, the 35-week RSA and behavioral measures were predictive of maternal and infant interaction behavior at 42 weeks. These preliminary findings suggest that an assessment protocol which includes social interaction behavior and RSA may be useful in identifying infants who are at greatest risk for developmental and relationship disturbances.