Section: New Results

Abnormal functional lateralization and activity of language brain areas in developmental dysphasia

Statistical analysis of white matter integrity for the clinical study of specific language impairment in children

Participants : Olivier Commowick, Aymeric Stamm, Camille Maumet, Jean-Christophe Ferré, Clément De Guibert, Christian Barillot.

Children affected by Specific Language Impairment (SLI) fail to develop a normal language capability. To date, the etiology of SLI remains largely unknown. It induces difficulties with oral language which cannot be directly attributed to intellectual deficit or other developmental delay. Whereas previous studies on SLI focused on the psychological and genetic aspects of the pathology, few imaging studies investigated defaults in neuroanatomy or brain function. We propose to investigate the integrity of white matter in Specific Language Impairment thanks to diffusion Magnetic Resonance Imaging. An exploratory analysis was performed without a priori on the impaired regions. A region of interest statistical analysis was performed based, first, on regions defined from Catani’s atlas and, then, on tractography-based regions. Both the mean fractional anisotropy and mean apparent diffusion coefficient were compared across groups. To the best of our knowledge, this is the first study focusing on white matter integrity in specific language impairment. 22 children with SLI and 19 typically developing children were involved in this study. Overall, the tractography-based approach to group comparison was more sensitive than the classical ROI-based approach. Group differences between controls and SLI patients included decreases in FA in both the perisylvian and ventral pathways of language, comforting findings from previous functional studies. This work was performed in collaboration with Emmanuel Vallée, Clément de Guibert, Catherine Allaire and Elisabeth Le Rumeur.