Study and Comparison of Formant Characteristics of Persian Vowels in 4-7-year-old Children Using Cochlear Implants and Those Using Hearing Aids

Background and Objective: One of the most important physical properties of vowels is their formant structure. One of the most obvious speech errors in hearing-impaired children is vowel errors. The present study aimed to determine and compare the formant structure of Persian vowels in deaf and cochlear implant children in the age range of 4-7 years. Materials and Methods: This descriptive-analytical cross-sectional study was performed on 21 children with serious hearing impairment and 17 children with cochlear implants in the age range of 4-7 years. After considering the inclusion and exclusion criteria, the vowel production test was administered. The first and second formant of each of the six vowels were obtained separately by Praat software and compared between the two groups. Results: There was a significant difference between deaf children and those with cochlear implants in the mean of the first and second formant of the /o/, as well as the mean of the first formant of the /i /, /a/, and /e / (P<0.05). Other vowel formants of the /æ/ and /u/ displayed no significant difference between the two groups (P>0.05). Conclusion: As evidenced by the results of this study, the first formant of Persian language vowels related to tongue height was different in the two groups. It signifies that the vowels in cochlear implant children are closer to normal, compared to those in hearing-impaired children with hearing aids.