Bifurcations and chaos in the cries of full-term and preterm infants

Pain-induced crying episodes were collected from groups of full-term and preterm infants and analyzed acoustically for the relative occurrence of various dysphonation segments. The crying episodes of full-term infants were found to contain a greater number of bifurcation and aperiodic segments compared to preterm infants. The results suggest that bifurcation and aperiodic segments are normally occurring phonatory events during infant crying. The differences observed between infant groups are discussed in regard to neuromaturational differences in infants' expression to a painful stimulus.