Acoustic Analysis of Crying Signal in Infants with Disabling Hearing Impairment

Crying is a multimodal, dynamic behavior and the first way to communicate. Early identification of hearing impairment is critical for prevention of speech and language disorders. The present study aimed to assess the acoustic features of infant's cry signals to find possible differences between two groups including hearing-impaired (HI) infants and normal hearing (NH) control.

The data were collected from 34 (17 HI, 17 NH) infants under 2 months of age. Recording of the infant cry signals was collected during the examination of the Babinski reflex and was subsequently submitted for acoustic analysis. The total duration of the recording for each infant was approximately 30 seconds. The acoustical features included fundamental frequency (F₀), formants (F₁, F₂, and F₃), intensity, jitter, shimmer, ratios of F₂/F₁ and F₃/F₁, ratio of harmonic to noise, and voice break. The recording device was an Olympus ws-321M voice recorder with 44,100 Hz sampling frequency in the stereo form. Praat analysis software (version 27, 3, 5) was used to analyze the crying signals. The data were then statistically analyzed using SPSS version 21.

Acoustic analysis of the crying signals showed that HI infants have lower intensity and higher F₀ and voice break than NH infants. However, the other differences were not statistically significant.

The results of the present study demonstrated that the acoustic components including F₀, intensity, and voice break may be used as indices to discriminate HI infants from NH infants under 2 months of age. These findings can be increased our knowledge concerning the functional mechanisms of the vocal organ in HI and NH infants.