A comparative study on syntactical skills of Persian-speaking hearing- impaired preschoolersand their normal-hearing peers

Introduction: Syntactical characteristics of hearing-impaired (named here after HI) children have been one of the main focuses of interest in speech and language pathology. In This study, HI children were compared with their normal counterparts in terms of MLU and the type and the number of error patterns in two types of speech samples (namely, free and descriptive speech). Materials and Methods: Sixteen Persian-speaking normal-hearing and 9 HI children aged from 48 to 72 monthswere evaluated in this cross-sectional descriptive-analytic study. All subjects were recruited from either nursery or rehabilitation centers of Tehran, Iran through the convenience sampling method. Story-retelling and complex-picture description tasks were used to obtain descriptive speech samples while free speech samples were collected via asking complementary questions. All samples were tape recorded for future quantitative and qualitative analyses. For statistical analysis of the data, Mann-Whitney's U and student's t tests were conducted. Results: Data analysis demonstrated a significant difference between the two groups with regard to the Mean length of utterance calculated inmorphemes (MLUm) in both free and descriptive speech samples (P < 0.001 and P = 0.002 respectively). The total mean of errors in both free (P < 0.001) and descriptive speech was significant different among the studied groups (P = 0.003). The most frequent syntactical errors in the descriptive speech of HI and normal children was incorrect deletion (48.5%) and incorrect selection (38.2%) respectively. Incorrect syntactical deletion had the highest frequency of occurrence in the free speech samples of both normal-hearingand hearing-impaired children (47.4% and 38.8% respectively). Conclusion: Beside their shorter MLU (especially in free speech), the nature of morphosyntagmatic errors of hearing-impaired children are different from typical children. Keywords: Persian language, Children, Hearing loss, Mean length of utterance, Syntactical skills