gms | German Medical Science

Objective: Most vestibular schwannoma (VS) patients experience a partial or complete hearing loss as well as tinnitus. Both symptoms are hypothesized to lead to cortical plasticity resulting in morphometric changes in an increase or decrease of the cortical thickness of the cortical and subcortical structures involving the auditory and limbic system. However, there is only few evidence in VS patients. The aim of the present study was to proof plastic changes in VS patients and their relation to the pre- and postoperative status of hearing and tinnitus.

Methods: The authors retrospectively analyzed gray (GM) and white matter (WM) volume of 103 cortical and subcortical brain regions by cortical-based morphometry in 46 VS patients (47,5 ± 11,6; 23 female). Subsequently, the volumetric results were referred to patients’ hearing status (i.e. Gardner-Robinson Classification) and tinnitus complaints by a Multivariate Analysis of Variance (MANOVA).

Results: There was no significant effect of either hearing status or tinnitus on WM. However, MANOVA showed a significant multivariate effect of hearing status and tinnitus on GM volume of different brain regions. Most prominent was an impact of the hearing status on the colliculus, while tinnitus influence the GM volume of the caudate.

Conclusion: Both hearing impairment as well as tinnitus are associated with GM but not with WM changes of cortical and subcortical regions in VS patients. These findings provide further insights in the pathophysiology of hearing impairment and chronic tinnitus in VS patients.