[ effect of hearing loss on acoustic parameters of voice in children]

ABSTRACT

By means of normal hearing system and appropriate auditory feedback, we can control acoustic parameters of voice such as phonation, quality of voice, pitch and intensity. The aim of this cross-sectional study was investigation and comparison of some acoustic parameters of voice including mean of intensity range, frequency range, shimmer, and harmonic to noise ratio between 2 groups of children [17 hearing impaired and 17 normal children]. These groups were matched with respect to age and sex. The mean of each parameters were calculated using collection of speech studio software and electrolaryngograph apparatus and were compared between two groups of children. The mean of intensity range between two groups was not statistically different [P=0.462]. The mean of frequency range between two groups was not statistically different either [P=0.277]. The mean of Shimmer in children with hearing loss was higher than normal children [P=0.010]. The mean of Harmonic to noise ratio [HNR] in children with hearing loss was lower than normal children [P=0.001]. It can be concluded that most susceptible acoustic parameters of voice for improving by hearing aids and speech therapy services are frequency and intensity range. The higher mean of shimmer and lower mean of harmonic to noise ratio [HNR] in hearing impaired children in comparison with normal group is caused by excessive pressure that these children are bearing on the larynx and related structures