Language disturbances in subjects with agenesis of the corpus callosum

There has been an increasing interest on the connections between higher cognitive functions and corpus callosum (CC). Among the others, language abilities are investigated in relation to acquired damage to the corpus callosum (e.g., closed head trauma and callosotomy), and to its congenital absence (ACC). This study explores language development in ACC. The sample is formed by eight individuals (four with partial ACC, four with complete ACC) with normal PIQ and no other CNS malformations, ranging from 4 to 24 years of age. A clinical assessment of all the language abilities (repetition, comprehension and production), at all the linguistic levels (phonology, semantic and syntax) was run by means of standardized tests. Results show that six individuals had some language impairments. Interhemispheric tactile transfer abilities were assessed too, as it has been hypothesized that they are unaffected in ACC, due to neuronal plasticity. Results show that callosal transfer appear to be suboptimal and atypical. The present study is the first one that systematically assesses language and interhemispheric tactile transfer abilities at the same time, showing that both are likely to be impaired in ACC. Results suggests that neurological plasticity may bring to suboptimal reorganization of cognitive functions