A Smart Preterm Breather: Variation of Cry Duration by Laryngeal Constriction Phenomena.

Abstract

Introduction and objective: Human neonates are born with some control over their larynx, which is essential for breathing, swallowing and phonation. Laryngeal constriction phenomena were observed during not provoked crying of full-term infants. As preterm infants show alterations in lung development and functionality, the aim of the present study was to examine whether these infants generate laryngeal constriction phenomena during the first week of life.

Methods: Cry vocalizations (n = 562) of 11 healthy, preterm infants (6 females) were analyzed visually (frequency spectrograms and oscillograms) and auditorily. The analyses of the occurrence of laryngeal constriction phenomena and the duration of vocalization were conducted using the open-source software PRAAT.

Results: Constriction phenomena were found in the crying of all preterm infants. No significant sex differences were observed. There was a significant correlation between the occurrence of laryngeal constriction phenomena and gestational age (r = -0.81). Vocalizations containing constriction phenomena were significantly longer than those without constrictions.

Conclusion: The study showed laryngeal constrictions as a regular phenomenon in cry vocalizations of preterm infants during their first week of life. They seemed to be mainly used as a respiratory mechanism to increase end-expiratory lung volume and to improve alveolar gas exchange.