Tehran University of Medical Sciences Auditory and Vestibular Research 2423-480X 25 1 2016 05 04 24 31 EN Peyman Zamani Hearing and Speech Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Masoud Motasaddi Zarandy Otorhinolarygology Research Center, Tehran University of Medical Sciences, Tehran, Iran Pedram Borghei Otorhinolarygology Research Center, Tehran University of Medical Sciences, Tehran, Iran Hossein Rezai Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Farzad Moubedshahi Otorhinolarygology Research Center, Tehran University of Medical Sciences, Tehran, Iran 2016 01 30 2016 03 12 Background and Aim: Age implantation is one of the effective factors on speech production outcomes in cochlear implanted (CI) children. The purpose of this study is to determine the role of age implantation on formant frequencies and production of three Persian vowels including /a/, /u/, /i/ in CI children. Methods: Sixty nine congenitally deaf children who received CI were divided into three groups based on their age implantation. The first and second formant frequencies of vowels, as dependent variables, were measured by SFS software 1.2. The role of children’s age imp­lantation and their gender, as effective factors, were analyzed using a 3 (implantation groups)×2 (gender) two-way ANOVA with a post hoc Bonferroni honest significant difference test in SPSS 16.0. Results: The mean values of F1/a/, F2/a/, F2/u/, F1/i/, F2/i/ were significantly different among different groups (p<0.05). 100% of children who received CI before the age of 2 produced vowels correctly. Types of vowel production disorders were mostly nasalization and backing in children who received CI between the ages of 3 to 4 and after age 5. Analysis showed that the effect of age implantation on formant frequ­encies of vowels was significant (p<0.05). Conclusion: Early age implantation (before 2) can cause an improvement of vowel production due to enhancement of F1 and F2 placement which is related to height and back-to-front movements of the tongue. Also, age impl­antation predicts the quality of vowel pro­duction. https://avr.tums.ac.ir/index.php/avr/article/view/91 https://avr.tums.ac.ir/index.php/avr/article/download/91/38