A review of some acoustic voice parameters in 6 to 11 years old children with severe to profound hearing impairment

AbstractIntroduction: A critical factor which affects human voice is hearing because it provides necessary feedback for voice and speech control. An intact auditory system as well as normal auditory feedback controls significant aspects of speech including vocal acoustics thus the person is able to correct the related mistakes. Normal vocal acoustics depends on auditory system.Materials and Methods: A cross sectional study on 27 subjects aged 6 to 11 with severe to profound bilateral hearing loss compared to 27 normal subjects. Participants matched according to age and gender, sampling was performed in Baghche-Ban specialty school and two elementary schools (Normal children). Further to hearing auditory tests, subjects voice were evaluated by a Visipitch III model 3900 hardware system and MDVP software model 5015 created by Kay-Pentax company (USA). All qualitative data were processed by Spss software, t.test and Pearson correlation.Results: In subjects with hearing impairment fundamental frequency (F0), the upper limit of fundamental frequency (F0 max) and Peak to Peak Amplitude Variation (vAm) were higher than the normal group and a statistically significant difference was found. Although shimmer (Amplitude Perturbation) and Jitter (Frequency Perturbation), Fundamental Frequency Variation (vF0) and Noise to Harmonic Ratio (NHR) in hearing loss group was more than normal group but no statistically significant difference was detected. There was significant correlation between NHR and shimmer and Jitter.Conclusion: Severe to profound hearing loss due to reduction of adequate auditory feedback  on acoustic voice parameters .The most significant changes happen in the  fundamental frequency and  vAm. Keywords: acoustic voice parameters, hearing impaired children, severe to profound hearing loss