Cortical and subcortical gray matter changes in patients with chronic tinnitus sustaining after vestibular schwannoma surgery

Abstract

Tinnitus is attributed to partial sensory deafferentation resulting in a central maladaptive neuroplasticity. Unfortunately, the agent of deafferentation is usually unknown or irreversible. In patients with unilateral vestibular schwannoma (VS), however, the auditory nerve is affected by a benign tumor. Hence, removal of the tumor can cease the tinnitus. In turn, sustaining complaints after surgery indicate cortical neuroplasticity. The present study is a cross sectional study which aims to track cortical structural changes by surface-based morphometry in 46 VS patients with sustained (i.e. centralized) or ceased (i.e. peripheral) tinnitus after surgery. A volumetric analysis of cortical and subcortical gray matter (GM) anatomy was performed on preoperative high-resolution MRI and related to the presence of hearing impairment, pre- and/or postoperative tinnitus. Patients with sustained (i.e. chronic) tinnitus showed an increased GM volume of the bilateral caudate nucleus, the contralateral superior colliculus, the middle frontal and middle temporal gyrus, the fusiform gyrus as well as the ipsilateral pars orbitalis when compared to those patients in whom tinnitus ceased postoperatively. Chronic tinnitus in VS patients is associated with characteristic structural changes in frontal, temporal and subcortical areas. Notably, a significant GM change of the caudate nucleus was detected providing further support for the striatal gaiting model of tinnitus.

Trading mental and physical health in vestibular schwannoma treatment decision

“…Tinnitus-related discomfort tended to improve slightly although previous reported “minimal clinically important difference” (MCID) could not be reached ( 25 ). This is concordant with previous studies demonstrating postoperative improvement in patients with preoperative tinnitus, while patients without preoperative tinnitus can develop a new-onset tinnitus after surgery in ~20% ( 32 – 34 ). Consequently, patients with preoperative severe tinnitus could be offered microsurgical resection of the VS, as radiotherapy may worsen tinnitus-related discomfort ( 35 ).…”

Vestibular Schwannoma and Tinnitus: A Systematic Review of Microsurgery Compared to Gamma Knife Radiosurgery

“…Trakolis et al studied 46 patients with spontaneous VSs who underwent surgical treatment and had sustained or ceased tinnitus postoperatively [ 30 ]. Preoperatively, 57% of the cohort had tinnitus with 22% of those with preoperative tinnitus having persistent tinnitus postoperatively and 62% having cessation of the tinnitus postoperatively.…”

“…This assessment was completed by two reviewers (J.C., A.K.) independently, with discrepancies resolved by discussion and consensus or discussion with the senior author [ 6 , 19 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ].…”