The influence of age and language on developmental trajectory of theory of mind in children with cochlear implants

Abstract

Objective: The present study investigates if children with cochlear implants (CI) are associated with delayed development of Theory of Mind (ToM) and the differences in gain of ToM ability with respect to age, language and other aspects of CI.Methods: One-hundred-eleven children with participation of their hearing parents, aged between 36 months and 132 months, who had congenital profound bilateral deafness and were unilateral CI users; plus 99 healthy children underwent 'Peabody Picture Vocabulary' and 'Sally-Anne' tests. A total of 77 children with CI (mean age: 76.51 months, 31 girls and 46 boys) and 82 healthy children (mean age: 72.41 months, 47 girls and 35 boys) were included in the analyses. Analytic comparisons were created between the controls and children with CI and between subgroups of CI users by univariate and multivariate analysis. The effects of age of hearing aid use, age of CI surgery, duration of CI use, language scores and the presence of risk factors, early rehabilitation with hearing aid and CI on the ToM development were analyzed.Results: The Sally-Anne test success rates of 67.1% were significantly higher in controls than that of children with CI (49.4%) (p < 0.05). The mean age difference of the children, who were successful in Sally-Anne test was 5.33 months in favor of healthy controls. The ToM task success rates were 57.1% (24/42) and 40% (14/35) in children with early CI and late CI respectively. The children, who were good at language, were also better in Sally-Anne tests, but the mean Peabody Picture Vocabulary test scores were indifferent in the same age group with respect to the presence of CI use (p > 0.05). However, multivariate analysis presented the higher language scores as the only significant independent variable that has impact on the success in Sally-Anne test (p < 0.05).Conclusion: The results revealed that among all children, who did better in ToM were older in age and better in language skills. Children with CI also performed better in false-belief test depending on their language scores. Early CI surgery, older age, and hence longer CI use can provide a well-developed ToM for children with CI.