Cortical thickness analysis and optimized voxel-based morphometry in children and adolescents with prelingually profound sensorineural hearing loss

Crossmodal neuroplastic changes following auditory deprivation in individuals with profound sensorineural hearing loss (SNHL) have been well documented in previous literature. However, previous studies have shown very little evidence of structural brain changes in individuals with prelingually profound SNHL and no studies have reported significant differences of gray matter (GM) in deaf subjects. Therefore, it is essential to employ a more specific and sensitive technique to detect subtle structural brain differences in deaf individuals. The objective of our study was to investigate neuroanatomical differences in children and adolescents with profound SNHL by cortical thickness analysis and optimized voxel-based morphometry (VBM). T1-weighted volumetric images of 16 children and adolescents with prelingually profound SNHL and 16 hearing controls were analyzed. The ANCOVA analysis revealed a statistically significant decreased average cortical thickness of the whole brain. As to vertex-based analysis, cortical thickness of the deaf subjects showed significant thinning in the left precentral gyrus, right postcentral gyrus, the left superior occipital gyrus and the left fusiform gyrus compared with the hearing subjects. VBM revealed statistically significant focal reduction of white matter (WM) volume in the left middle frontal gyrus and the right inferior occipital gyrus in deaf subjects without statistically significant differences in GM volume between the two groups. These findings demonstrated that structural changes happened not only in the WM but also in the GM of the subjects with prelingually profound SNHL, which have never been reported before in any previous literature. Our results also implicated the potential neuroplastic changes associated with crossmodal reorganization in the brain after auditory deprivation in the early deafness.