Determination and comparison of reaction time of phonation in stutterers and non-stutterers in two group of age 10-20, 20-30

AbstractIntroduction: Some researcher suggest that stuttering is a temporal disruption of the simultaneous and successive programming of muscular movements required to produce a speech sound and they say  speech  motor in stutterers associated with reduced timing variable rather than  non stutterers such as reaction time. Reaction time is a standard criterion that can show nature of differences of phonation between stutterers and non-stutterers. The aim of this study is determination and comparison of reaction time of phonation in stutterers and non-stutterers   .materials and Methods: this was descriptive- analytic study and selected 22 stutterers and 22 no stutterers from 10-30 years old and request them when heard stimulation as quickly as possible in response then recorded both of stimulation and answers by Praat software and measured interval between them.Result: result of this study show mean of reaction time in stutterers is more than no stutterers and this difference is more significant in 20-30 years old. But differences in two group of age do not significant.Conclusion:  to consider, there is problem in voice onset in stutterers so this problem can be result from slower VRT could result problem such as struggle, avoiding and anticipatory behaviors, disorder in neuro-motor factors, timing force that stutterers feel in this task that this problem specially in adult stutteres are more than children because they have more experience in stuttering.Keyword: stuttering, reaction time, fluent speech, Praat software