Outcomes at 6 months are related to brain structural and white matter microstructural reorganization in idiopathic tinnitus patients treated with sound therapy

Abstract

This study aimed to explore brain structural and white matter microstructural reorganization in the early stage of tinnitus and identify brain alterations that contribute to its relief after 6 months of sound therapy. We studied 64 patients with idiopathic tinnitus, including 29 patients who were categorized into an effective group (EG) and 35 who were categorized into an ineffective group (IG) according to the 6‐month follow‐up improvement of the Tinnitus Handicap Inventory score, along with 63 healthy controls (HCs). All participants underwent structural and diffusion tensor imaging scanning on a 3‐T magnetic resonance system. Differences in brain gray/white matter volume and white matter microstructure were evaluated using voxel‐based morphometry analysis and tract‐based spatial statistics among the three groups. Associations between brain reorganization and the improvement of tinnitus symptoms were also investigated. Compared with EG patients, IG patients experienced a significant gray matter volume decrease in the right middle frontal gyrus (MFG)/right precentral gyrus (PreCG). Meanwhile, both EG and IG patients showed significant changes (decrease or increase) in brain white matter integrity in the auditory‐related or nonauditory‐related white matter fiber tracts compared with HCs, while EG patients showed decreased axial diffusivity in the bilateral middle cerebellar peduncle (MCP) compared with IG patients. We combined the gray matter change of the MFG/PreCG and the white matter integrity of the bilateral MCP as an imaging indicator to evaluate the patient's prognosis and screen patients before treatment; this approach reached a sensitivity of 77.1% and a specificity of 82.8%. Our study suggests that there was a close relationship between brain reorganization and tinnitus improvement. The right MFG/PreCG and bilateral MCP may be indicators that can be used to predict prognoses in patients with idiopathic tinnitus and may be used to screen patients before sound therapy. These findings may provide new useful information that can lead to a better understanding of the tinnitus mechanism.

Pretreatment intranetwork connectivity can predict the outcomes in idiopathic tinnitus patients treated with sound therapy

“…Our latest study proved that idiopathic tinnitus patients with different outcomes (effective or ineffective) after sound therapy experienced distinct brain structural reorganization (Chen et al, 2021a). Thus, the main objective of this study was met by providing convincing data about whether the different prognoses of tinnitus patients after sound therapy can be associated with the differences in brain network connectivity.…”

“…To date, few studies have applied brain alterations to predict therapeutic outcomes or even screen patients before sound therapy (Chen et al, 2021a; Han, Yawen, et al, 2019; Han, Na, et al, 2019). For example, (Han, Yawen, et al, 2019; Han, Na, et al, 2019) used neural network nodes to predict the improvements in patient symptoms after sound therapy and found that features of the bilateral thalami were the best indicators, with adjusted AUC values of under 0.8.…”

“…For example, (Han, Yawen, et al, 2019; Han, Na, et al, 2019) used neural network nodes to predict the improvements in patient symptoms after sound therapy and found that features of the bilateral thalami were the best indicators, with adjusted AUC values of under 0.8. In another study (Chen et al, 2021a), they found that the gray matter and WM microstructure in combination could be an optimal imaging biomarker to predict the efficacy of sound therapy in patients with tinnitus. In our study, we applied the combination of intranetwork FC changes in the right IFG of the aDMN and the left STG of the AUN as an indicator to screen patients and evaluate the prognosis before sound intervention, which reached relatively ideal specificity and sensitivity and PPV and NPV simultaneously.…”

“…All the patients were asked to complete the THI to assess tinnitus severity before and after treatment, and the primary outcome of the current study was the changes in THI score. Based on prior studies, we defined tinnitus patients with a reduction of 17 points or more in THI scores or reduced to 16 points as the EG (Chen et al, 2021a; Zeman et al, 2011), while those with a decrease in THI scores that did not meet either of these two conditions were defined as IG. Accordingly, the patients were divided into two groups: 35 patients were classified into an EG, and 43 patients were classified into an IG.…”

“…Thus, the mechanism by which acoustic therapy is effective or ineffective in tinnitus patients is still unclear, and it cannot be predicted whether the particular method is suitable or not for some patients. Meanwhile, our latest study revealed that significant differences existed in the GMV and white matter microstructure in some areas or fibers between the sound therapy effective group (EG) and ineffective group (IG), which indicated that there may be distinct mechanisms of neural remodeling between these groups of patients (Chen et al, 2021a). Therefore, it is unknown whether such a difference existed in the resting‐state network (RSN) connections between the EG and IG, as previous studies have shown functional abnormalities play an important role in tinnitus generation (Chen, Zheng, et al, 2018; Chen, Zhang, et al, 2018; Feng et al, 2018; Han, Yawen, et al, 2019; Han, Na, et al, 2019; Schmidt, Carpenter‐Thompson, & Husain, 2017; Zhou et al, 2019).…”