Patterns of breath intervals during non-nutritive sucking in full-term and ‘at risk’ preterm infants with normal neurological examinations

The interaction between respiration and non-nutritive sucking rhythms was investigated in 12 sleeping, normal, full-term, newborn infants and in 14 preterm infants who were examined repeatedly at 34, 40 and 46 wk of conceptional age. Full-term infants showed a shortening of breath intervals in the middle of sucking bursts and a lengthening of the breath interval spanning the end of sucking bursts. The differences were more marked in females than males.A rhythm interaction between sucking and respiration was also observed in preterm infants as young as 34 wk of conceptional age. Clinical neurological examinations did not discriminate between pretern infants above and below a median score for optimal obstetric conditions, but the interaction between breathing and sucking rhythms made such a discrimination, most clearly in females. Preterm infants with lower optimal obstetric scores showed less change of breath durations during sucking than preterms with higher scores. It was concluded that interaction of concurrent motor rhythms may be a sensitive index of central nervous system integrity in newborn infants, even when there are no clinical neurological signs of nervous system dysfunction.