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Brain structural and functional reorganization in tinnitus patients without hearing loss after sound therapy: a preliminary longitudinal study1Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China, 2Department of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, China
Synopsis
Idiopathic tinnitus patients experienced significant differences in auditory-related and nonauditory-related brain reorganization before and after sound therapy (narrow band noise), that is, sound therapy may have a significant effect on brain reorganization in patients with idiopathic tinnitus.
Purpose
Sound therapy is one of the most common first-line treatments for idiopathic tinnitus. We aimed to investigate the brain structural and functional alterations between patients with idiopathic tinnitus without hearing loss (HL) and healthy controls (HCs) and between patients before and after sound therapy.Methods
Structural and resting-state functional images were acquired from 13 tinnitus patients without HL and 18 HCs before and after 6 months of sound therapy (only patients received the treatment). Voxel-based morphometry (VBM) and independent component analysis (ICA) were conducted to separately investigate the brain structural and functional changes. Associations between brain changes and clinical variables were also performed.Results
After sound therapy, the %improvement of THI score was -1.30% (± 63.40%). Compared with HCs, tinnitus patients showed gray matter and white matter atrophy in the left middle temporal gyrus at baseline, and the gray matter volume was further reduced after the treatment. The patients also showed increased white matter volume in the cingulum (cingulate), right calcarine, left rolandic operculum, and left parietal and frontal lobes. Additionally, compared with HCs, tinnitus patients exhibited positive [medial visual network (mVN) and sensorimotor network (SMN), mVN and auditory network (AN)] and negative [mVN and lateral visual network (lVN)] internetwork functional connectivity (FC) at baseline and negative [left frontoparietal network (LFPN) and dorsal attention network (DAN), AN and posterior default mode network (pDMN)] internetwork FC after sound therapy. The patients also showed negative [LFPN and right frontoparietal network (RFPN), LFPN and RFPN, anterior default mode network (aDMN) and AN, aDMN and DAN] internetwork FC after the treatment when compared with baseline.Conclusion
Our findings suggest that although the outcomes of idiopathic tinnitus patients without HL were not very good when the improvement of THI scores was used as an evaluation indicator, the patients experienced significant differences in auditory-related and nonauditory-related brain reorganization before and after sound therapy (narrow band noise), that is, sound therapy may have a significant effect on brain reorganization in patients with idiopathic tinnitus. This study may provide some new useful information for the understanding of mechanisms underlying idiopathic tinnitus.Acknowledgements
The authors thank the patients and healthy volunteers who participated in this study and gave generously of their time.References
1. Chen, Q., Wang, Z., Lv, H., Zhao, P., Yang, Z., and Gong, S., et al. (2020). Reorganization of Brain White Matter in Persistent Idiopathic Tinnitus Patients Without Hearing Loss: Evidence From Baseline Data. Front Neurosci 14, 591. doi: 10.3389/fnins.2020.00591.
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4. Lv, H., Liu, C., Wang, Z., Zhao, P., Cheng, X., and Yang, Z., et al. (2020). Altered functional connectivity of the thalamus in tinnitus patients is correlated with symptom alleviation after sound therapy. Brain Imaging and Behavior 14(6), 2668-2678. doi: 10.1007/s11682-019-00218-0.
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Figures
Figure4 Intergroup differences in internetwork FC between the tinnitus patients and HCs and between the patients before and after sound therapy.
(A) Compared with the HCs, the tinnitus patients exhibited a decreased (i.e., positive) (mVN and lVN) or an increased (i.e., less negative) (mVN and SMN; mVN and AN) internetwork FC at baseline.
