Acoustic Analysis of Neonatal Crying According to Body Weight, Sex and Delivery Type

Song, Chang Youn; Wang, Soo Geun; Koo, Soo Kweon; Kim, Hyun Kyu; Han, Chul Woo; Kweon, Soon Bok

Abstract

BACKGROUND AND OBJECTIVES
Crying is the only mode of communication, which simultaneously reflects a variety of complex neurophysiologic and laryngeal functions in neonates. Acoustic analysis of crying, as an early noninvasive screening measure of the neurophysiological integrity, can reveal important information about the biological status of neonate. The purpose of this research was to establish normative acoustic data on healthy neonatal crying. This study also attempted to find out the differences in the pattern of healthy neonatal crying according to body weight, sex and delivery type (normal spontaneous vaginal delivery and Cesarean section). SUBJECTS AND METHOD: Crying of 33 healthy full term neonates (19 males, 14 females) were sampled within 1 wk postpartum. All neonates were free of any respiratory, laryngeal, CNS pathology according to the charts reviewed at one month. All neonates were considered to have normal hearing as they passed a hearing screening test using Evoked Otoacoustic Emission (EOAE). Body weight, sex, delivery type and Apgar score (1 min, 5 min) were measured. The acoustic characteristics of neonatal crying were analyzed by CSL (Computerized Speech Lab) using parameters such as fundamental frequency (F0), Jitter (%), Shimmer (%), NHR and formant frequency (F1, F2, F3). Statistics were analyzed by independent T-test, pearson's correlation coefficients (p<0.05, by SPSS ver 10.0). RESULTS: Mean body weight and Apgar score (1 min, 5 min) of all subjects were within normal range. Mean fundamental frequency (F0) value of healthy full term neonatal crying was 411.1 Hz. This value showed a shift to higher frequencies in neonates born by spontaneous vaginal delivery (SVD) than Cesarean section (C-sec) delivery, and so, in males than females. But statistic significance in F0 between delivery types, and between sex were not found (p-value 0.158, 0.508). Mean Jitter (%), Shimmer (%) and NHR value were 2.02, 8.34 and 0.32, respectively. These values showed a shift to higher in neonates born by C-sec delivery than SVD, and also in males than females. But statistical significance in these parameters between delivery types, and between sex were not found (p-value 0.442, 0.841, 0.301, 0.082, 0.070, 0.244). Formant frequency F1, F2 and F3 were 1882.4 Hz, 3877.9 Hz and 6053.6 Hz, respectively. There was no statistically significant difference in these values between sex, and delivery types (p-value 0.619, 0.785, 0.953, 0.255, 0.698, 0.636). For the healthy full term neonates, F0 value had a tendency to decrease as the body weight increases. But there was no significantly strong negative correlations between them. (r=-0.324, p-value 0.066). Other acoustic parameters didn't show any statistically significant relevance with body weight, either. CONCLUSION: Body weight, sex and delivery type had little influence over acoustic parameters of healthy full term neonatal crying. However, this acoustic analysis of crying could be helpful in differentiating between normal and abnormal neonates, and in screening CNS dysfunction, neurophysiologic and laryngeal abnormality.