Basic Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jul 6, 2019; 7(13): 1582-1590
Published online Jul 6, 2019. doi: 10.12998/wjcc.v7.i13.1582
Neural metabolic activity in idiopathic tinnitus patients after repetitive transcranial magnetic stimulation
Ying Kan, Wei Wang, Shu-Xin Zhang, Huan Ma, Zhen-Chang Wang, Ji-Gang Yang
Ying Kan, Wei Wang, Shu-Xin Zhang, Huan Ma, Ji-Gang Yang, Department of Nuclear Medicine, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
Zhen-Chang Wang, Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
Author contributions: Kan Y, Wang ZC, and Yang JG designed the research; Kan Y, Wang W, and Zhang SX performed the research; Kan Y and Ma H analyzed the data; Kan Y wrote the paper.
Supported by the National Natural Science Foundation of China, No. 81771860.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board of Beijing Friendship Hospital, Capital Medical University and adhered to the tenets of the Declaration of Helsinki.
Conflict-of-interest statement: None.
Data sharing statement: Technical appendix, statistical code, and dataset are available from the corresponding author at [cjr.wzhch@vip.163.com]. Participants gave informed consent for data sharing. No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Zhen-Chang Wang, MD, Chief Doctor, Professor, Department of Radiology, Capital Medical University, Beijing Friendship Hospital, No. 95, Yongan Road, Xicheng District, Beijing 100050, China. cjr.wzhch@vip.163.com
Telephone: +86-10-63138625 Fax: +86-10-63138625
Received: March 6, 2019
Peer-review started: March 8, 2019
First decision: April 18, 2019
Revised: April 21, 2019
Accepted: May 2, 2019
Article in press: May 2, 2019
Published online: July 6, 2019
Abstract
BACKGROUND

The central mechanism of idiopathic tinnitus is related to hyperactivity of cortical and subcortical auditory and non-auditory areas. Repetitive transcranial magnetic stimulation (rTMS) is a well-tolerated, non-invasive potential treatment option for tinnitus.

AIM

To investigate the changes of neural metabolic activity after rTMS in chronic idiopathic tinnitus (IT) patients.

METHODS

Eleven patients underwent rTMS (1 Hz, 90% motor threshold, 1000 stimuli/day for consecutive 10 d) on the left temporoparietal region cortex. Tinnitus handicap inventory (THI) and visual analogue score (VAS) were assessed at baseline and posttreatment. All patients underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography to evaluate the neural metabolic activity. Data were preprocessed using statistical parametric mapping and Gretna software to extract the regions of interest (ROIs). The correlation between brain areas involved and THI scores was analyzed.

RESULTS

Baseline and posttreatment parameters showed no significant difference regarding THI score (t = 1.019, P = 0.342 > 0.05) and VAS (t = 0.00, P = 1.0 > 0.05). Regions with the highest FDG uptake were the right inferior temporal gyrus (ITG), right parahippocampa gyrus (PHG), right hippocampus, rectus gyrus, left middle frontal gyrus, and right inferior frontal gyrus in IT patients. After rTMS treatment, IT patients showed increased activities in the right PHG, right superior temporal gyrus, right superior frontal gyrus, anterior insula, left inferior parietal lobule, and left precentral gyrus, and decreased activities in the left postcentral gyrus and left ITG. The ROIs in the right parahippocampa gyrus and right superior frontal gyrus were positively correlated with THI scores (r = 0.737, P = 0.037 < 0.05; r = 0.735, P = 0.038 < 0.05).

CONCLUSION

Our study showed that 1-Hz rTMS directed to the left temporo-parietal junction resulted no statistically significant symptom alleviation. After treatment, brain areas of the limbic and prefrontal system showed high neutral metabolic activity. The auditory and non-auditory systems together will be the target for rTMS treatment.

Keywords: Tinnitus, Brain imaging, Metabolism, Positron emission tomography

Core tip: In this study, we focused on changes of neural metabolic activity in idiopathic tinnitus (IT) patients after repetitive transcranial magnetic stimulation (rTMS) treatment and further investigated changes in cortical activities of the whole brain. We found that after rTMS treatment, IT patients had increased activities in auditory, non-auditory, and limbic systems, and the activity decreased only in the target area with no statistically significant symptom alleviation. Our study may provide a new direction for rTMS target area.