Gray matter reduction in the fusiform gyrus in Spanish children with dyslexia

Abstract

Voxel-based morphometry studies have reported reduced gray matter volume in temporal areas (fusiform gyrus) and cerebellum in children with developmental dyslexia compared to healthy controls. These areas with less gray matter volume have been linked to reading skills impairments, as these areas are related to reading automaticity and word recognition. However, most of the patients in these studies were speakers of languages with a deep orthography. The current study used 25 Spanish children (age range 9-14 years; mean age= 12.05 years; 12 healthy controls and 13 dyslexic children).VBM was employed to determine the differences between the dyslexic and healthy control groups, and the children performed different phonological tasks to determine their scores on reading skills. Voxel-based morphometry revealed significantly reduced gray matter volume in the fusiform gyrus (left) and cerebellum in dyslexic children compared to the healthy control group. In addition, when we correlated the scores on the phonological task with the gray matter volume, the dyslexic children mainly showed less gray matter volume in the fusiform gyrus on word reading time and pseudoword reading time tasks, and less GMV in the thalamus on the verbal fluency (FAS-F) task. Results are consistent with the idea that reading problems in languages with a shallow orthography are related to dysfunctions in the fusiform area.