title: Transcutaneous electrical stimulation at auricular acupoints innervated by auricular branch of vagus nerve pairing tone for tinnitus: study protocol for a randomized controlled clinical trial.
abstract: BACKGROUND
  Subjective tinnitus is a phantom sensation experienced in the absence of any source of sound. Its mechanism remains unclear, and no approved drugs are available. Vagus nerve stimulation (VNS) is an exciting new method to treat tinnitus, but direct electrical stimulation of the cervical vagus has disadvantages. This randomized controlled clinical trial aims to overcome these limitations by stimulating the auricular branch of vagus nerve (ABVN) on the outer ear. Since the ABVN is the only peripheral branch of the vagus nerve distributed on the ear's surface, it should be possible to achieve analogous efficacy to VNS by activating the central vagal pathways. However, researches have indicated that the curative effect lies in a combination of auditory and vagal nerve stimulation. Moreover, from traditional Chinese theory, auricular acupoints used to treat tinnitus are mainly in the regions supplied by the ABVN. Whether stimulation at the auricular acupoints is due to unintentional stimulation of vagal afferent fibers also needs evidence.
  
  
  METHODS
  A total of 120 subjects with subjective tinnitus are randomized equally into four groups: (1) electrical stimulation at auricular acupoints (CO10, CO11, CO12, and TF4) innervated by the ABVN; (2) electrical stimulation at auricular acupoints (CO10, CO11, CO12, and TF4) innervated by ABVN pairing tones; (3) electrical stimulation at auricular acupoints innervated by non-ABVN pairing tones; (4) electrical acupuncture. Patients will be treated for 30 minutes every other day for 8 weeks. The primary outcome measure is the Tinnitus Handicap Inventory. The secondary outcome measure combines a visual analogue scale to measure tinnitus disturbance and loudness with the Hospital Anxiety and Depression Scale. Assessment is planned at baseline (before treatment) and in the 4th and 8th week, with further follow-up visits after termination of the treatment at the 12th week. Any adverse events will be promptly documented.
  
  
  CONCLUSIONS
  Completion of this trial will help to confirm whether ABVN or the combination of ABVN and sound stimulus plays a more important role in treating tinnitus. Moreover, the result of this clinical trial will enhance our understanding of specific auricular acupoints.
  
  
  BACKGROUND
  Chinese Clinical Trials Register ChiCTR-TRC-14004940.
authors: Medical College of China Three Gorges University, No. 8, University Avenue, Yichang, Hubei, China. 919033846@qq.com.
authors: Tian-Tian
authors: TT
authors: Li
authors: Medical College of China Three Gorges University, No. 8, University Avenue, Yichang, Hubei, China. 1450025693@qq.com.
authors: Zhao-Jun
authors: ZJ
authors: Wang
authors: Yichang Hospital of Traditional Chinese Medicine, Clinical Medical College of Traditional Chinese Medicine, China Three Gorges University, Yichang, Hubei, 443003, China. maypaul@163.com.
authors: Song-Bai
authors: SB
authors: Yang
authors: Yichang Hospital of Traditional Chinese Medicine, Clinical Medical College of Traditional Chinese Medicine, China Three Gorges University, Yichang, Hubei, 443003, China. 1006730212@qq.com.
authors: Jun-Hong
authors: JH
authors: Zhu
authors: Medical College of China Three Gorges University, No. 8, University Avenue, Yichang, Hubei, China. 1020825212@qq.com.
authors: Shi-Zhong
authors: SZ
authors: Zhang
authors: Medical College of China Three Gorges University, No. 8, University Avenue, Yichang, Hubei, China. 106680558@qq.com.|Yichang Hospital of Traditional Chinese Medicine, Clinical Medical College of Traditional Chinese Medicine, China Three Gorges University, Yichang, Hubei, 443003, China. 106680558@qq.com.
authors: San-Jin
authors: SJ
authors: Cai
authors: Medical College of China Three Gorges University, No. 8, University Avenue, Yichang, Hubei, China. 404028301@qq.com.
authors: Wen-Han
authors: WH
authors: Ma
authors: Medical College of China Three Gorges University, No. 8, University Avenue, Yichang, Hubei, China. 1977238997@qq.com.
authors: Ding-Qi
authors: DQ
authors: Zhang
authors: Medical College of China Three Gorges University, No. 8, University Avenue, Yichang, Hubei, China. zhigangmei@139.com.|Yichang Hospital of Traditional Chinese Medicine, Clinical Medical College of Traditional Chinese Medicine, China Three Gorges University, Yichang, Hubei, 443003, China. zhigangmei@139.com.
authors: Zhi-Gang
authors: ZG
authors: Mei
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D015669:Acupuncture Points; D000293:Adolescent; D000328:Adult; D000368:Aged; D001307:Auditory Perception; D002681:China; D002985:Clinical Protocols; D003131:Combined Modality Therapy; D004185:Disability Evaluation; D054644:Ear Auricle / Q000294:innervation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012107:Research Design; D016037:Single-Blind Method; D013997:Time Factors; D014012:Tinnitus / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D004561:Transcutaneous Electric Nerve Stimulation / Q000379:methods*; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000503:physiopathology*; D055815:Young Adult