Content area
Full Text
Abstract
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.
Copyright (C) 2003 S. Karger AG, Basel
KeyWords
Full-term infants * Preterm infants * Acoustic analysis * Cry * Dysphonation
Introduction
Acoustic characterization of infant crying has been of interest to researchers for over 50 years, dating back to Fairbanks [1], who examined the pitch of infant hunger wails. Since then, most infant cry research has centered on correlating an infant's neurobehavioral integrity with his or her corresponding laryngeal behavior [2]. Corwin and Golub [3] suggested there are four distinct types of acoustic cry vocalizations (or segments) that an infant may produce during a complete bout (i.e., episode) of crying. One of these cry vocalizations occurs while the infant is inspiring air, and the remaining three types of cry vocalizations occur on expiratory airflow. The first type of cry vocalization, termed inspiratory phonation, was described by Fisichelli et al. [4] as a gasping inhalation of air following a burst of crying that is strong enough to produce vocal fold vibration. The three types of expiratory vocalizations are cry phonation, cry hyperphonation, and cry dysphonation. Cry phonation is characterized as a periodic cry vocalization with a fundamental frequency (F^sub 0^) between 250 and 700 Hz. Cry hyperphonation is also periodic but higher in F^sub 0^ (1,000-2,000 Hz). Cry dysphonations encompass a wide range of fluctuating F^sub 0^ and/or intensity patterns and may contain aperiodic energy [5].
Essentially all studies of normal and disordered infant groups focus exclusively on cry phonation and hyperphonation [6, 7]. Far less is known about inspiratory phonations and cry dysphonations. Grau et al. [8] performed a detailed acoustic study of inspiratory phonation. These researchers found inspiratory phonation to be a regularly occurring feature among normal newborns, whereby the stress and strain placed on the vocal folds during crying contribute...