Genetic and Congenital Cytomegalovirus-Related Hearing Loss in Children: Volumetric MRI Analysis of Auditory and Visual Cortices.

BACKGROUND AND PURPOSE Although effects of deafness on the brain have been reported, little is known about the differential impact of genetic versus acquired etiologies. Our purpose was to assess cortical volumetric differences and hemispheric asymmetry in children with gap junction protein beta-2 (GJB2)- and congenital cytomegalovirus (cCMV)-related hearing loss compared with age- and sex-matched controls.

MATERIALS AND METHODS In this retrospective study, 3D T1-weighted sequences of children with cCMV-related hearing loss, GJB2-related hearing loss, and normal hearing were analyzed using FreeSurfer volumetric segmentation. Cortical volumes of Heschl gyrus (HG), planum polare (PP), planum temporale (PT), lateral aspect of superior temporal gyrus (LSTG), primary visual cortex, and cuneus were assessed. We performed a linear mixed model analysis to investigate cortical volumetric differences between 1:3 case:control-matched groups, adjusting for age, sex, and field strength. The laterality index was calculated to assess hemispheric asymmetry, and a 2-tailed 1-sample t test was used to compare the distribution of values against zero. Statistical significance was determined at a threshold of P < .05.

RESULTS Twenty-two children with cCMV-related hearing loss, 7 children with GJB2-related hearing loss, and 87 age- and sex-matched children with normal hearing were included. Significant differences were observed between the cortical volumes in the right (P = .03), left (P = .03), and total cuneus (P = .02) between GJB2-related hearing loss and controls; HG (P = .02) and PT (P < .001) on the right; LSTG (P = .002) on the left; and the total HG (P = .02) and PT (P < .001) between cCMV-related hearing loss and controls. HG was significantly larger on the left in GJB2-related SNHL (P = .01), and the HG, PT, and LSTG were significantly larger on the left with a significantly larger right cuneus in both cCMV-related hearing loss and controls (P < .01).

CONCLUSIONS GJB2-related hearing loss is associated with volumetric alterations in the visual cortices, and alterations in the auditory cortical regions occur in cCMV-related hearing loss. Particular auditory areas showed significant leftward asymmetry in GJB2- and cCMV-related hearing loss and controls. In contrast, the visual areas showed significant rightward asymmetry in both CMV-related hearing loss and controls.