Authors: Emilia Kaniewska¹, Fatima Husain¹, Gibbeum Kim¹, Rafay Khan²
¹University of Illinois
²Icometrix
Introduction: Both tinnitus and hearing loss are known to impact the brain’s neuroplasticity; however, findings have been inconsistent. This project examines neuroanatomical changes within a military population, aiming to broaden our understanding of these disorders in a more homogenous population.
Methods: MRI and audiometric data were collected for 68 participants at Wilford Hall Ambulatory Surgical Center (WHASC) within the Joint Base San Antonio (JBSA) at Lackland Air Force Base (USA). Data acquisition was performed using a 3T Siemens Verio full-body scanner. Structural changes in gray matter were investigated using voxel-based morphometry (VBM) on T1-weighted images, analyzed with the Computational Anatomy Toolbox (CAT12) with Statistical Parametric Mapping (SPM12) in MATLAB. Diffusion-weighted images were processed and analyzed for fractional anisotropy (FA) using the Tract-based Spatial Statistics (TBSS) toolbox within the FMRIB Software Library (FSL).
Results: VBM analysis revealed no significant results at the corrected level (FWE p < 0.05) for either effect of tinnitus, hearing loss, or combined. In contrast, DTI results, as shown in Figure 1, indicated a significant effect of hearing loss in the right anterior thalamic radiation, left superior longitudinal fasciculus, and right corticospinal tract. Additionally, the combined effect of hearing loss and tinnitus was observed in the forceps minor, right superior longitudinal fasciculus, and left inferior longitudinal fasciculus. No changes were detected for the effect of tinnitus alone.
Conclusion: Based on our results, we hypothesize that white matter tracts may be more vulnerable to chronic tinnitus and hearing loss, manifesting more changes compared to alterations in gray matter. Additionally, based on previous work in our lab and other centers, we propose that while hearing loss has a greater effect on white matter integrity changes, tinnitus may modulate some of these changes, exhibiting a preserving influence on neuroanatomy.
