Different cortical metabolic activation by visual stimuli possibly due to different time courses of hearing loss in patients withGJB2andSLC26A4mutations

Abstract

Conclusion.We have demonstrated differences in cortical activation with language-related visual stimuli in patients who were profoundly deafened due to genetic mutations in GJB2 and SLC26A4. The differences in cortical processing patterns between these two cases may have been influenced by the differing clinical courses and pathogenesis of hearing loss due to genetic mutations. Our results suggest the importance of hearing during early childhood for the development of a normal cortical language network.Objectives.To investigate the cortical activation with language-related visual stimuli in patients who were profoundly deafened due to genetic mutations in GJB2 and SLC26A4.Methods:The cortical activity of two adult patients with known genetic mutations (GJB2, SLC26A4) was evaluated with fluorodeoxyglucose-positron emission tomography (FDG-PET) with a visual language task and compared with that of normal-hearing controls.Results:A patient with a GJB2 mutation showed activation in the right auditory association area [BA21, BA22], and the left auditory association area [BA42] even with visual language task; in contrast, a patient with an SLC26A4 mutation showed no significant activation in the corresponding area.

Glucose Metabolism in the Primary Auditory Cortex of Postlingually Deaf Patients: An FDG-PET Study

“…In addition, this cross-modal plasticity is suppressed and replaced by normal development if the child uses a hearing prosthesis such as a hearing aid or a cochlear implant to increase his or her spoken language skills [11,12]. …”