Preterm birth is associated with an increased fundamental frequency of spontaneous crying in human infants at term-equivalent age.

Yuta Shinya,Masako Myowa-Yamakoshi,Masahiko Kawai,Fusako Niwa

doi:10.1098/rsbl.2014.0350

Abstract

Human infant crying has been researched as a non-invasive tool for assessing neurophysiological states at an early developmental stage. Little is known about the acoustic features of spontaneous cries in preterm infants, although their pain-induced cries are at a higher fundamental frequency (F0) before term-equivalent age. In this study, we investigated the effects of gestational age, body size at recording and intrauterine growth retardation (IUGR) on the F0 of spontaneous cries in healthy preterm and full-term infants at term-equivalent age. We found that shorter gestational age was significantly associated with higher F0, although neither smaller body size at recording nor IUGR was related to increased F0 in preterm infants. These findings suggest that the increased F0 of spontaneous cries is not caused by their smaller body size, but instead might be caused by more complicated neurophysiological states owing to their different intrauterine and extrauterine experiences.

Highlights

Acoustic features of infant crying have been studied as a possible non-invasive tool for assessing neurophysiological states [1,2,3,4,5]
We investigated the effects of gestational age, body size at recording and intrauterine growth retardation (IUGR) on F0 to assess the relationship between preterm birth and the F0 of spontaneous cries at term-equivalent ages
We examined the differences between the small for gestational age preterm (SGAP) and adequate for gestational age preterm (AGAP) groups using the two-tailed Student’s t-test; there were no differences between the groups for any of the F0 variables

Summary

Introduction

Acoustic features of infant crying have been studied as a possible non-invasive tool for assessing neurophysiological states [1,2,3,4,5]. As preterm infants exhibit reduced vagal activity even at term-equivalent age [7], the F0 of their cries might be affected by the altered vagal activity as well as smaller body size. The effects of body size and other factors related to neurophysiological states (e.g. intrauterine growth retardation (IUGR)) on the F0 of cries in preterm infants have not been investigated [2,3,4].

Results

Conclusion