Gap Detection Threshold in Children with Down Syndrome: A Brief Report

Background and Aim: Auditory discrimination is one of reasons for low performance of phonological processing in people with Down syndrome. This study aims to evaluate the auditory discrimination performance of children with Down syndrome to explore a reason for deficit in phonological processing in these children. Methods: In this descriptive cross-sectional study, 16 Persian-speaking elementary school male students with Down syndrome participated. Phonetic gap detection test was used to evaluate their auditory temporal threshold. They were asked to discriminate the sounds of six syllables at 20, 50, 100, 200 and 300 ms temporal gaps. Results: The mean of phonetic gap detection threshold was 246.8 ms, ranged 183.3–300 ms. There was no significant correlation between auditory temporal thresholds and the factors of age or intelligence quotient. Conclusion: Children with Down syndrome discriminate the sounds of syllables at higher thresholds compared to normal peers examined in previous studies. Increased gap detection threshold may be an underlying cause for low performance of these children in phonological processing. Keywords: Auditory temporal processing; phonological processing; intellectual disability; working memory; auditory discrimination; auditory acuity