Cardiorespiratory reactivity during the Brazelton Scale in term and preterm infants.

Determined the relationship between behaviour measured with the Brazel zelton Scale and simultaneously recorded cardiorespiratory activity. The Brazelton Scale was administered and videotaped in a sample of 22 term and 22 preterm infants at term conceptional age. The videotapes were coded off line with a computer interface to time lock behavior and physiological activity for the duration of four alert, non-crying conditions. Term infants showed increases in heart rate and breathing rate when unswaddled and cuddled following cry and increases in respiratory sinus arrhythmia (RSA) during orientation and swaddling. Preterm infants showed the same general trend as term infants in heart rate and breathing rate. However, RSA decreased during orientation in preterm infants. On behavioral scores, preterm infants showed lower scores on self-regulation and a higher cost of attention. Correlations between behavior and physiological activity showed lower RSA associated with enhanced behavioral scores for the preterm infants. Results of this study are consistent with the hypothesis that attentional responsivity in the preterm infant may be at the expense of physiological stability.