Effect of bilingualism on volume of corpus callosum

Background and aim: in spite of the effect of the left hemisphere domination on first language acquisition in human, studies suggest activities and the role of both hemispheres in learning second language. therefore learning a second language requires more communication between the two hemispheres. regarding the role of the corpus callosum as the only data-centric interface between the two hemispheres, the aim of this study was to evaluate and compare the volume of the corpus callosum in monolingual and bilingual individuals.methods: this cross-sectional study was conducted on 24 samples, 16 simultaneous bilinguals (eight kurdish-persian, eight turkish-persian)and eight monolinguals with age range of 18 to 30 years, all right handed, and in equal numbers in both sexes (female and male), volume of corpus callosum determined by mri. data was analyzed by parametric and non-parametric statistical tests.results: the volume of corpus callosum is smaller in monolinguals in comparison with bilinguals,in which a significant difference was observed (p=0.04).conclusion: according to the language data transmission and the rate of processing by the corpus callosum between two hemispheres,it seems for improving the quality of aural rehabilitation,the findings of present study will be useful before performing programs like auditory training, language learning, and by development of neuroplasticity which is often decoded by stimulus that occur in the hemisphere in contrast to the dominant hemisphere.