Cry analysis in infants resuscitated for apnea of infancy

Abstract

Objective: The purpose of the present study was to examine the acoustic features of crying demonstrated by infants who experienced apnea of infancy (AOI) and compare these features to a non-AOI group of infants. Based on past physiological descriptions of AOI, three predictions in regard to the influence of AOI on acoustic cry features were proposed: (1) the rate of crying would be significantly faster among infants with AOI, (2) the latency of crying onset would be significantly longer among infants with AOI and (3) the F(0) characterizing an overall episode of crying would be significantly lower among infants with AOI.

Patients and methods: Pain-induced crying episodes were collected from a group of healthy term infants (HT) and those with AOI. One complete crying episode was obtained from each infant and analyzed acoustically with regard to durational and spectral features of the cry.

Results: Infants comprising the AOI group were found to demonstrate a significantly longer cry latency and lower F(0) compared to HT infants.

Conclusions: The acoustic cry features measured for the AOI infants are discussed with regard to past reports of poor arousal and decreased muscle tone. A model of AOI crying is proposed whereby the autonomic nervous system and associated pathways are slower to interpret pain stimulus compared to HT infants.

Figure 1

Amplitude-by-time waveform displays of the crying episode of a healthy term (HT) infant (panel A) and an infant with apnea of infancy (AOI) (panel B). The waveforms depict instances of several expiratory cries comprising the overall crying episode. Each crying episode was preceded by an audible tone that was time-locked to administration of the pain stimulus. The tone served as the acoustic reference for measurement of cry latency.