Language predictors of theory of mind in cochlear implant children compared to normal-hearing peers

Background and Aim: Theory of mind (ToM) is very necessary to have successful social interaction. Hearing impairment disrupts the ToM development and language acquisition. This study aimed to compare ToM abilities of children with cochlear implant (CI) and normal hearing (NH) to clarify the role of language skills in ToM development. Methods: Participants were CI and NH children in two age ranges of 5−6 and 8−9 years. Main measures were basic and advanced tasks of ToM test (Abbreviated as B. ToM and A. ToM), and comprehension of mental–state verbs and relative clauses. Regression analysis was used to assess how language skills predict ToM. Results: CI children obtained significantly lower scores in all subscales of ToM test (p ≤ 0.001). Regression models for CI group aged 5−6-year showed that their comprehension of mental-state verbs predicted 53% of B. ToM. In CI children aged 8−9 years, comprehension of relative clauses and mental-state verbs together predicted 61% of B. ToM and 73% of A. ToM variances. Furthermore, comprehension of rela­tive clauses predicted 43% of B. ToM and 31% of A. ToM in younger NH children. Conclusion: Comprehension of mental-state verbs can predict only B. ToM in CI children aged 5−6 years and both B. ToM and A. ToM in CI children aged 8−9 years. Therefore, it is the main factor to predict ToM ability of preschool and school-age children with CI. The role of language should be considered by people who are helping these children for their cognitive problems. Keywords: Theory of mind; mental verb; relative clause; cochlear implant