Korean medicine combination treatment for chronic tinnitus unresponsive to conventional treatment: A case report and review of literature

BACKGROUND

Tinnitus is a common condition in otolaryngology; however, its pathophysiological mechanisms remain incompletely elucidated. Recent efforts have focused on improving individual treatment efficacy by combining different treatment approaches. Therefore, this study aimed to reveal the efficacy of Korean medicine (KM) combination therapy in treating chronic tinnitus unresponsive to conventional Western treatments.

CASE SUMMARY

A 35-year-old female patient with over 10 years of left-sided tinnitus, accompanied by left eye twitching, headache, neck pain, and premenstrual syndrome, was diagnosed with liver qi stagnation. She underwent 11 sessions involving acupuncture-related treatments and Chuna therapy as part of KM treatment. From the 9^th session onward, temporomandibular joint balancing therapy was incorporated. Following the treatment, tinnitus, headache, and neck pain resolved, while other symptoms improved, as reflected in the rating scores (tinnitus handicap inventory: 68 to 0, headache impact test-6: 64 to 36, neck disability index: 21 to 0). Significant improvement in tinnitus, headache, and neck pain was observed after just two KM treatment sessions; intermittent tinnitus ceased entirely after the 9th session, and improvements were maintained at the 2-month follow-up.

CONCLUSION

In conclusion, personalized treatment with a combination and modification of various KM therapies based on individual pattern diagnosis effectively alleviated daily life discomfort in a patient with chronic tinnitus, unresponsive to conventional treatments. This led to a rapid resolution of symptoms within a relatively short timeframe.

Reducing Tinnitus via Inhibitory Influence of the Sensorimotor System on Auditory Cortical Activity

Tinnitus is the subjective perception of a sound without corresponding external acoustic stimuli. Research highlights the influence of the sensorimotor system on tinnitus perception. Associated neuronal processes, however, are insufficiently understood, and it remains unclear how and at which hierarchical level the sensorimotor system interacts with the tinnitus-processing auditory system. We therefore asked 23 patients suffering from chronic tinnitus (11 males) to perform specific exercises, aimed at relaxing or tensing the jaw area, which temporarily modulated tinnitus perception. Associated neuronal processes were assessed using magnetencephalography. Results show that chronic tinnitus patients experienced their tinnitus as weaker and less annoying after completion of relaxing compared with tensing exercises. Furthermore, (1) sensorimotor alpha power and alpha-band connectivity directed from the somatosensory to the auditory cortex increased and (2) gamma power in the auditory cortex reduced, which (3) related to reduced tinnitus annoyance perception on a trial-by-trial basis in the relaxed state. No effects were revealed for 23 control participants without tinnitus (six males) performing the same experiment. We conclude that the increase in directed alpha-band connectivity from the somatosensory to the auditory cortex most likely reflects the transmission of inhibition from the somatosensory to the auditory cortex during relaxation, where concurrently tinnitus-related gamma power reduces. We suggest that revealed neuronal processes are transferable to other tinnitus-modulating systems beyond the sensorimotor one that is involved in attentional or emotional tinnitus modulation and provides deeper mechanistic insights into how and through which channels phantom sound perception might be modulated on a neuronal level.

[Patient-reported outcome measures-use in diagnosing depression, anxiety, and stress]

Patient-reported outcome measures (PROMs) is an umbrella term for various self-report instruments used to assess subjective health-related impressions and treatment success from the patient's perspective. In psychosomatic medicine, PROMs are often used to record subjective symptoms, psychosocial distress, and changes in health status, particularly in patients with comorbid (affective) disorders and frequent contact with physicians, but also in preventive health care and to monitor the effectiveness of treatment. In otolaryngology (ENT), self-report questionnaires (PROMs) are used, among other things, to assess the impact of hearing, speech, swallowing, and breathing disorders on patients' quality of life. Such scientifically validated tools make it possible to better understand the needs and priorities of patients and to integrate them into clinician-patient communication and treatment to promote individual, patient-centered care. Three dimensions for the assessment of subjective health-related experiences (depression, anxiety, stress) with corresponding instruments for the German-speaking area for use in clinical and research settings are presented in more detail, specifically for otolaryngology.

Decoding tinnitus progression: neurochemical shifts in the anterior cingulate cortex revealed by magnetic resonance spectroscopy

Background

Tinnitus persists as a significant public health challenge with elusive neurochemical underpinnings. Emerging evidence implicates dysregulated excitatory-inhibitory neurotransmission in the anterior cingulate cortex (ACC), a limbic-auditory hub governing tinnitus salience. This study investigates dynamic ACC neurochemical changes during tinnitus progression.

Methods

Using single-voxel magnetic resonance spectroscopy (MRS), GABA+/creatine (Cr) and Glx (glutamate+glutamine)/Cr ratios were measured in the ACC of 16 recent-onset (RO; <6 months), 22 chronic (CH; ≥6 months) tinnitus patients, and 26 healthy controls (HC). Tinnitus severity was assessed via tinnitometry and Tinnitus Functional Index (TFI).

Results

RO patients exhibited significantly reduced ACC GABA+/Cr compared to CH and HC groups (p < 0.05), while CH and HC showed no differences. GABA+/Cr positively correlated with tinnitus duration across patients (r = 0.364, p = 0.025). Although Glx/Cr did not differ between groups, elevated Glx/Cr associated with higher tinnitus pitch-matching frequencies (r = 0.421, p = 0.008) and emotional distress (TFI-E; r = 0.370, p = 0.022), though these findings did not survive multiple comparison correction.

Conclusion

Early tinnitus is characterized by ACC GABAergic deficits, while chronicity features normalized GABA+/Cr levels-suggesting compensatory neuroplastic restoration of inhibition over time. Glutamatergic activity may modulate perceptual and emotional dimensions of tinnitus. These phase-specific ACC neurochemical shifts highlight potential therapeutic targets for arresting tinnitus progression. Longitudinal studies are warranted to validate temporal dynamics.

Continuous Improvement of Chronic Tinnitus Through a 9-Month Smartphone-Based Cognitive Behavioral Therapy: Randomized Controlled Trial

BACKGROUND

Tinnitus is the perception of sound without an external auditive stimulus and can be a severe burden for affected patients. Medical guidelines recommend cognitive behavioral therapy (CBT) for tinnitus treatment, which effectively improves tinnitus-related distress and anxiety.

OBJECTIVE

This study investigates the outcome of a 9-month smartphone-based CBT for patients with tinnitus.

METHODS

The randomized controlled clinical trial in this study investigates the efficacy of a smartphone-based CBT for 187 patients with chronic tinnitus over a 9-month treatment period. In the initial 3 months, a waiting list design was applied, and in the subsequent study phase, the data of both treatment groups were collectively analyzed. The scores on the Tinnitus Questionnaire (TQ); 9-item Patient Health Questionnaire (PHQ-9); 9-item Self-Efficacy, Optimism, Pessimism (SWOP-K9) questionnaire; and 20-item Perceived Stress Questionnaire (PSQ-20) were assessed as endpoints after 3 and 9 months of treatment.

RESULTS

We observed a statistically significant reduction in the tinnitus burden in patients who received the smartphone-based CBT intervention. Although no changes were observed initially in the TQ sum scores in the waiting control group (baseline mean, 37.8, SD 4.7; 3 months mean 37.5, SD 4.8; analysis of covariance [ANCOVA] P=.52), the scores significantly decreased once the app-based CBT had commenced. Data pooled from both groups revealed significant reduction in the TQ sum score by 12.49 (SD 1.44) (ANCOVA, P<.001) and 18.48 (SD 1.85) (ANCOVA, P<.001) points after 3 and 9 months, respectively, which was also clinically important. The calculated Cohen d was 1.38. Similarly, the scores on PSQ-20 (-9.14 points; ANCOVA, P<.001), PHQ-9 (-2.47 points; ANCOVA, P<.001), and SWOP-K9 (0.17 points; ANCOVA, P<.001) were significantly improved at the end of the therapy, with corresponding intermediate effect sizes after 9 months.

CONCLUSIONS

The data in our study provide evidence of statistically significant, clinically relevant, and continuous benefits of an app-based CBT intervention in patients with chronic tinnitus.

TRIAL REGISTRATION

Deutsches Register Klinischer Studien DRKS00022973; https://drks.de/search/de/trial/DRKS00022973.

Clinical phenotype and management of sound-induced pain: Insights from adults with pain hyperacusis

Pain hyperacusis, also known as noxacusis, causes physical pain in response to sounds that do not bother most people. How sound causes excruciating pain that can last for weeks or months is not well understood, resulting in a lack of effective treatments. To gain insight into the underlying mechanisms of the condition, 32 adults attended a virtual focus group to describe their sound-induced pain. Focus group data were used to develop three follow-up surveys that aimed to identify the most common symptoms of pain hyperacusis as well as the participants' use of therapies for pain relief. All participants endorsed negative effects of pain hyperacusis on psychosocial and physical function. Most reported sound-induced burning (80.77%), stabbing (76.92%), throbbing (73.08%), and pinching (53.85%) sensations that occur either in the ear or elsewhere in the body. Participants have used numerous pharmaceutical and non-pharmaceutical interventions to alleviate their pain with varying degrees of pain relief. Benzodiazepines and nerve blockers emerged as the most effective analgesic options while non-pharmaceutical therapies were largely ineffective. Symptoms and therapeutic approaches were generally consistent with peripheral mechanistic theories of pain hyperacusis (e.g., trigeminal nerve involvement). An interdisciplinary approach to clinical studies and the development of animal models are needed to identify and treat the pathological mechanisms of pain hyperacusis. PERSPECTIVE: This article presents the physical and psychosocial consequences of debilitating sound-induced pain (i.e., pain hyperacusis) and the interventions that sufferers have sought for pain relief. The results are largely consistent with peripheral mechanistic theories (e.g., trigeminal nerve involvement) and will guide future work to investigate neural mechanisms and effective therapies.

Association between obstructive sleep apnea and Tinnitus in the United States: NHANES 2005-2020

BACKGROUND

This study aimed to investigate the association between Obstructive Sleep Apnea (OSA) and Tinnitus using NHANES data from 2005 to 2020.

METHODS

This study analyzed data from NHANES (National Health and Nutrition Examination Surveys) conducted between 2005 and 2020, and included 4871 participants aged 16 or older. OSA was assessed using the Multivariate Apnea Prediction Index and the variables from the National Health and Nutrition Examination Survey. Tinnitus was defined as participants who reported being bothered by a ringing, roaring, or buzzing sound in the ears or head lasting 5 min or more during the past 12 months. Logistic regression models were employed to examine the association between OSA and Tinnitus.

RESULTS

The study cohort had an overall prevalence of Tinnitus of 16.5%, with 53.51% for males and 46.49% for females. After controlling for potential confounders, there was a significant association between Tinnitus and OSA (odds ratio = 1.43, 95% confidence interval = 1.05-1.94, P = 0.03).

CONCLUSION

These findings indicate that OSA is a risk factor for the development of Tinnitus.

Role of transcutaneous electrical nerve stimulation in alleviation of tinnitus in normal hearing subjects

BACKGROUND

Subjective tinnitus is characterized by perception of sound in the absence of any external or internal acoustic stimuli. Many approaches have been developed over the years to treat tinnitus (medical and nonmedical). However, no consensus has been reached on the optimal therapeutic approach. Electrical nerve stimulation targeting peripheral auditory pathways presents a promising area of investigation for the treatment of tinnitus. Non-invasive transcutaneous vagal nerve stimulation of the auricular branch of the vagus nerve has been introduced and studied but its success rate varies and conflicting results have been reported. In this study we aim to assess the role of transcutaneous electrical nerve stimulation in alleviation of tinnitus in normal hearing subjects and to study the different factors that may affect the degree of alleviation of tinnitus.

METHODS

The study group consisted of 64 subjects (38 male and 26 female). The age ranged between 20 and 60 years. All of them suffering from subjective tinnitus. Assessment of tinnitus loudness analyzed by Visual Analogue Scale (VAS) which was applied before and directly after TENS stimulation.

RESULTS

There is a statistically significant difference in tinnitus loudness before and after TEN stimulation as assessed by VAS. 45 out of 64 (70.31%) patients had improvement after TENS, from them nine patients had a complete reduction of tinnitus. There is no statistically significant relation between the studied variables and the degree of tinnitus reduction.

CONCLUSION

ta-VNS is an effective treatment of subjective tinnitus but we could not assess for how long this residual inhibition persists due to lack of long term follow up. However, it is difficult to decide who might benefit from ta-VNS, patients with unilateral tinnitus on right ear and those with whistling sound have more reduction in tinnitus loudness than others.

Digital Frequency Customized Relieving Sound for Chronic Subjective Tinnitus Management: Prospective Controlled Study

BACKGROUND

Tinnitus is a major health issue, but currently no tinnitus elimination treatments exist for chronic subjective tinnitus. Acoustic therapy, especially personalized acoustic therapy, plays an increasingly important role in tinnitus treatment. With the application of smartphones, personalized acoustic stimulation combined with smartphone apps will be more conducive to the individualized treatment and management of patients with tinnitus.

OBJECTIVE

The aim of this study was to evaluate the efficacy of a new personalized approach known as the digital frequency customized relieving sound (DFCRS) for tinnitus treatment and to explore the factors that may influence its therapeutic effect.

METHODS

Patients with subjective tinnitus were enrolled in this study from July 14, 2020, to May 24, 2021, in the tinnitus specialist clinic of Eye and ENT Hospital, Fudan University, Shanghai, China. In this nonrandomized concurrent controlled trial, a total of 107 participants were assigned to listen to personalized DFCRS through our developed app, while the other 77 participants who did not want to download and use the app were assigned to listen to unmodified music (UM). All the recruits were instructed to listen to DFCRS or UM for at least 2 hours a day and complete follow-up assessments at baseline, 1, 2, and 3 months. Multidimensional assessment scales, that is, Tinnitus Handicapped Inventory (THI), Hospital Anxiety and Depression Scale (HADS), Athens Insomnia Scale (AIS), Fear of Tinnitus Questionnaire (FTQ), and Tinnitus Catastrophizing Scale (TCS) were used to evaluate the severity of tinnitus and the quality of life. Linear mixed models were used to test for changes in the THI scores across 3 months of acoustic treatment between group (DFCRS or UM treatment) and time. A multiclass logistic model was built with a stepwise function to determine the influence of the different covariates on the effects of acoustic treatment.

RESULTS

The results of the multidimensional assessment scales after 3 months of treatment showed that DFCRS-treated patients had significant tinnitus relief compared to those in the UM group. Linear mixed models revealed a significant reduction in the THI scores over time (P<.001), with the DFCRS group showing significantly greater improvement than the UM group (P<.001). At 3 months, 92.5% (99/107) of the patients undergoing DFCRS reported tinnitus relief or disappearance, and longer daily treatment time was associated with better outcomes (P=.007). Multiclass logistic regression confirmed that longer treatment time (odds ratio [OR] 13.07-64.78; P<.001) and more severe tinnitus at baseline (OR 10.46-83.71; P<.001) predicted better treatment response. All secondary outcomes (HADS, AIS, FTQ, TCS) showed significant improvements over time (P<.001).

CONCLUSIONS

Our study suggests that DFCRS is a new promising and noninvasive therapy for chronic tinnitus, and it can be delivered through a mobile app to bring more convenience to patients with tinnitus.

A prospective cohort study of cochlear implantation as a treatment for tinnitus in post-lingually deafened individuals

BACKGROUND

Cochlear implants have helped over one million individuals restore functional hearing globally, but their clinical utility in suppressing tinnitus has not been firmly established.

METHODS

In a decade-long study, we examined longitudinal effects of cochlear implants on tinnitus in 323 post-lingually deafened individuals including 211 with pre-existing tinnitus and 112 without tinnitus. The primary endpoints were tinnitus loudness and tinnitus handicap inventory. The secondary endpoints were speech recognition, anxiety and sleep quality.

RESULTS

Here we show that after 24 month implant usage, the tinnitus cohort experience 58% reduction in tinnitus loudness (on a 0-10 scale from 4.3 baseline to 1.8 = -2.5, 95% CI: -2.7 to -2.2, p = 3 x 10-6; effect size d' = -1.4,) and 44% in tinnitus handicap inventory (=-21.2, 95% CI: -24.5 to -17.9, p = 1 x 10-15; d'=-1.0). Conversely, only 3.6% of those without pre-existing tinnitus develop it post-implantation. Prior to implantation, the tinnitus cohort have lower speech recognition, higher anxiety and poorer sleep quality than the non-tinnitus cohort, measured by Mandarin monosyllabic words, Zung Self-rating Anxiety Scale and Pittsburgh Sleep Quality Index, respectively. Although the 24 month implant usage eliminate the group difference in speech and anxiety measures, the tinnitus cohort still face significant sleep difficulties likely due to the tinnitus coming back when the device was inactive at night.

CONCLUSIONS

The present result shows that cochlear implantation can offer an alternative effective treatment for tinnitus. The present result also identifies a critical need in developing always-on and atraumatic devices for tinnitus patients, including potentially those with normal hearing.

The Current State of Tinnitus Diagnosis and Treatment: a Multidisciplinary Expert Perspective

Tinnitus, the perception of sound without an external source, affects 15% of the population, with 2.4% experiencing significant distress. In this review, we summarize the current state of knowledge about tinnitus management with a particular focus on the translation into clinical practice. In the first section, we analyze shortcomings, knowledge gaps, and challenges in the field of tinnitus research. Then, we highlight the relevance of the diagnostic process to account for tinnitus heterogeneity and to identify all relevant aspects of the tinnitus in an individual patient, such as etiological aspects, pathophysiological mechanisms, factors that contribute most to suffering, and comorbidities. In the next section, we review available treatment options, including counselling, cognitive-behavioral therapy (CBT), hearing aids and cochlear implants for patients with a relevant hearing loss, sound generators, novel auditory stimulation approaches, tinnitus retraining therapy (TRT), pharmacological treatment, neurofeedback, brain stimulation, bimodal stimulation, Internet- and app-based digital approaches, and alternative treatment approaches. The evidence for the effectiveness of the various treatment interventions varies considerably. We also discuss differences in current respective guideline recommendations and close with a discussion of how current pathophysiological knowledge, latest scientific evidence, and patient perspectives can be translated in patient-centered care.

Ginkgo biloba extract prescriptions are associated with less frequent repeat visits to ENT doctors due to tinnitus: a retrospective cohort study

Objectives

We aimed to evaluate the drug utilization of Ginkgo biloba extract (Gbe), systemic corticosteroids (CSs), and pentoxifylline (PTXF) for the treatment of acute tinnitus by analyzing electronic patient health record data. In addition, we assessed whether the different drug treatments were associated with different frequencies of repeat visits to ear, nose, and throat (ENT) doctors.

Methods

This retrospective cohort study used data from the IQVIA Disease Analyzer (DA) database. It included patients with an initial diagnosis of tinnitus between January 2005 and December 2021, treated by ENT specialists in Germany.

Results

Of 111,629 patients meeting all selection criteria, 51,205 received prescriptions of Gbe, 34,817 of systemic CSs, and 25,607 of PTXF. Gbe prescription was associated with significantly lower odds of a repeat consultation due to tinnitus compared to systemic CSs [odds ratio (OR) 0.91; 95% confidence interval (CI): 0.88-0.95] as well as PTXF (OR 0.74; 95% CI: 0.72-0.77). This association was significant in both men and women and in some age groups.

Conclusion

Gbe is the most frequently ENT specialist-prescribed drug for the treatment of acute tinnitus. It is associated with a reduced likelihood of patients consulting their ENT specialist for tinnitus again compared to systemic CSs and PTXF.

Current status of transcutaneous auricular vagus nerve stimulation for tinnitus: a narrative review of modern research

Tinnitus, characterized by phantom sound perception, is a highly disruptive disorder lacking definitive and effective treatments. Its intricate neural mechanisms are not fully understood. Transcutaneous auricular vagus nerve stimulation (taVNS) has demonstrated potential as a substitute or supplementary treatment by activating central vagal pathways. However, standardized therapeutic protocols and objective tests to assess efficacy are lacking. Therefore, taVNS shows promise as a therapy for tinnitus, and treatment protocols should be optimized in future clinical trials.

Tinnitus: Clinical Insights in Its Pathophysiology-A Perspective

Tinnitus, the perception of sound without a corresponding external sound source, and tinnitus disorder, which is tinnitus with associated suffering, present a multifaceted clinical challenge due to its heterogeneity and its incompletely understood pathophysiology and especially due to the limited therapeutic options. In this narrative review, we give an overview on various clinical aspects of tinnitus including its heterogeneity, contributing factors, comorbidities and therapeutic pathways with a specific emphasis on the implications for its pathophysiology and future research directions. Tinnitus exhibits high perceptual variability between affected individuals (heterogeneity) and within affected individuals (temporal variability). Hearing loss emerges as predominant risk factor and the perceived pitch corresponds to areas of hearing loss, supporting the compensatory response theory. Whereas most people who have tinnitus can live a normal life, in 10-20% tinnitus interferes severely with quality of life. These patients suffer frequently from comorbidities such as anxiety, depression or insomnia, acting as both risk factors and consequences. Accordingly, neuroimaging studies demonstrate shared brain networks between tinnitus and stress-related disorders shedding light on the intricate interplay of mental health and tinnitus. The challenge lies in deciphering causative relationships and shared pathophysiological mechanisms. Stress, external sounds, time of day, head movements, distraction, and sleep quality can impact tinnitus perception. Understanding these factors provides insights into the interplay with autonomic, sensory, motor, and cognitive processes. Counselling and cognitive-behavioural therapy demonstrate efficacy in reducing suffering, supporting the involvement of stress and anxiety-related networks. Hearing improvement, especially through cochlear implants, reduces tinnitus and thus indirectly validates the compensatory nature of tinnitus. Brain stimulation techniques can modulate the suffering of tinnitus, presumably by alteration of stress-related brain networks. Continued research is crucial for unravelling the complexities of tinnitus. Progress in management hinges on decoding diverse manifestations, identifying treatment-responsive subtypes, and advancing targeted therapeutic approaches.

Efficacy and safety of transcutaneous auricular vagus nerve stimulation (ta-VNS) in the treatment of tinnitus: protocol for an updated systematic review and meta-analysis

INTRODUCTION

With an increasing incidence and significant effects on patients, tinnitus has become a major disease burden. There is a dearth of therapies with established efficacy for tinnitus. Transcutaneous auricular vagus nerve stimulation (ta-VNS) is being investigated as a potential therapy for tinnitus, but the current body of evidence remains inconclusive due to conflicting results across different studies. As a result, this protocol aims to synthesise and update the evidence to clarify whether ta-VNS is effective and safe for alleviating tinnitus.

METHODS AND ANALYSIS

To identify relevant randomised controlled trials (RCTs), seven representative bibliographical databases will be searched from their inception to December 2023: PubMed, Embase (via OVID), Cochrane Library, Chinese National Knowledge Infrastructure, Wangfang Database, Chinese BioMedical Literature Database, and Chongqing VIP Chinese Science and Technology Periodical Database. Publications in English or Chinese will be considered for inclusion. RCTs comparing ta-VNS with active treatments, no intervention, waitlist control or sham ta-VNS in adult patients with subjective tinnitus will be included. Studies on objective tinnitus will be excluded. Primary outcome is tinnitus symptom severity measured by validated scales. With all eligible trials included, when applicable, quantitative analysis via meta-analyses will be performed using RevMan V.5.4.1 software. Otherwise, a qualitative analysis will be conducted. The methodological quality of the included RCTs will be assessed using the Risk of Bias 2.0 tool. Sensitivity analyses, subgroup analysis and publication bias evaluation will also be performed. The Grading of Recommendations, Assessment, Development, and Evaluation approach will be used to grade the certainty of the evidence.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review, as no primary data will be collected. The results will be reported and disseminated through publication in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022351917.

Noise-induced hearing loss alters potassium-chloride cotransporter KCC2 and GABA inhibition in the auditory centers

Homeostatic plasticity, the ability of neurons to maintain their averaged activity constant around a set point value, is thought to account for the central hyperactivity after hearing loss. Here, we investigated the putative role of GABAergic neurotransmission in this mechanism after a noise-induced hearing loss larger than 50 dB in high frequencies in guinea pigs. The effect of GABAergic inhibition is linked to the normal functioning of K + -Cl- co-transporter isoform 2 (KCC2) which maintains a low intracellular concentration of chloride. The expression of membrane KCC2 were investigated before and after noise trauma in the ventral and dorsal cochlear nucleus (VCN and DCN, respectively) and in the inferior colliculus (IC). Moreover, the effect of gabazine (GBZ), a GABA antagonist, was also studied on the neural activity in IC. We show that KCC2 is downregulated in VCN, DCN and IC 3 days after noise trauma, and in DCN and IC 30 days after the trauma. As expected, GBZ application in the IC of control animals resulted in an increase of spontaneous and stimulus-evoked activity. In the noise exposed animals, on the other hand, GBZ application decreased the stimulus-evoked activity in IC neurons. The functional implications of these central changes are discussed.

Neuromodulation for Treatment of Tinnitus: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the treatment efficacy of neuromodulation versus sham for the treatment of tinnitus.

DATA SOURCES

Cochrane Library, CINAHL, PubMed, Scopus.

REVIEW METHODS

The Cochrane Library, CINAHL, PubMed, and Scopus were searched from inception through May 2023 for English language articles documenting "neuromodulation" and "tinnitus" stratified by sham-controlled randomized control trials with 40 or more patients. Data collected included Beck Anxiety Inventory, Beck Depression Inventory (BDI), Tinnitus Handicap Inventory (THI), Tinnitus Questionnaire, and Visual Analog Scale. A Meta-analysis of continuous measures (mean) and proportions (%) were conducted.

RESULTS

A total of 19 randomized control trials (N = 1186) were included. The mean age was 48.4 ± 5.3 (range: 19-74), mean duration of tinnitus was 3.8 ± 3.4 years, 61% [56.2-65.7] male, and 55.7% [46-65] with unilateral tinnitus. The short-term effect of transcutaneous electrical nerve stimulation and transcranial direct current stimulation on THI score is -16.2 [-23.1 to -9.3] and -19 [-30.1 to -7.8], respectively. The long-term effect of repetitive transcranial magnetic stimulation on THI score is -8.6 [-11.5 to -5.7]. Transcranial direct current stimulation decreases BDI score by -11.8 [-13.3 to -10.3].

CONCLUSION

As measured by the Tinnitus Handicap Index, our findings suggest the effects of transcutaneous electrical nerve stimulation and transcranial direct current stimulation reach significant benefit in the short term, whereas repetitive transcranial magnetic stimulation reaches significant benefit in the long term. Based on the BDI, transcranial direct current stimulation significantly reduces comorbid depression in patients with tinnitus.

AUDISTIM® Day/Night Alleviates Tinnitus-Related Handicap in Patients with Chronic Tinnitus: A Double-Blind Randomized Placebo-Controlled Trial

The aim of this study is to evaluate the efficacy of taking a daily supplement based on active compounds (AUDISTIM® Day Night: A D/N) in alleviating tinnitus-related disability, as suggested by previous real-life studies. This double-blind randomized placebo-controlled study was conducted in adults with mild to severe tinnitus receiving a 3-month supplementation with A D/N (magnesium, vitamins, phytochemicals) or placebo (excipients without active ingredients). Tinnitus-related handicap (THI), psychological stress (MSP-9), and sleep quality (PSQI) were assessed at baseline and during intervention, perceived impression of tinnitus improvement at the end of the follow-up. The full set analysis included 114 patients (59 A D/N, 55 placebo) aged 53.8 ± 11.4 years, 58% women, with fluctuating (45%) or permanent (55%) tinnitus from 9.3 ± 9.4 years. A D/N supplementation led to greater changes in THI (-13.2 ± 16.0 vs. -6.2 ± 14.4, p = 0.0158,Cohen's d =0.44) at 3 months (primary outcome), especially with continuous tinnitus (-15.0 ± 16.3 vs. -4.6 ± 12.8, p = 0.0065), and, to a lesser extent, at 1 month (-9.8 ± 13.1 for A vs. -4.3 ± 12.1, p = 0.0213). PSQI significantly improved over time in both groups, but MSP-9 only with A D/N. In lines with previous observational studies, both clinical (THI score > 7 pts) and statistical (vs. placebo) improvement, more pronounced in permanent tinnitus, demonstrate the effectiveness of the combination of active compounds and support its use in the management of mild to severe tinnitus.

Development of a Prognostic Nomogram for Modified Tinnitus Relieving Sound Therapy for Subjective Tinnitus

OBJECTIVE

We aimed to develop a modified tinnitus-relieving sound system and establish a model for predicting its treatment effects.

STUDY DESIGN

Retrospective study.

SETTING

Tinnitus Specialist Clinic of Eye & ENT Hospital, Fudan University.

METHODS

We recruited 107 patients undergoing modified tinnitus-relieving sounds between August 2020 and May 2021. Patients were divided into training (n = 75) and validation (n = 32) cohorts in a 7:3 ratio. The treatment outcome was Tinnitus Handicapped Inventory scores. Features were established using a least absolute shrinkage and selection operator-derived logistic regression model, where the selected clinical risk factors were included in the multivariate logistic regression, and a nomogram was established based on the model. The discrimination and calibration abilities of the nomogram were evaluated using the Hosmer-Lemeshow test and calibration curves. Decision curve analysis (DCA) was used to evaluate the net benefit of predictive efficacy.

RESULTS

Multivariate logistic analysis indicated that the initial Tinnitus Handicapped Inventory score (odds ratio [OR]: 1.13 [1.07-1.19], P < .001) and treatment duration (OR: 3.4 [1.34-8.62], P < .001) were positive factors for improved tinnitus. The nomogram model that included baseline Tinnitus Handicapped Inventory score and treatment duration achieved a better concordance index of 0.880. DCA revealed that the nomogram model could lead to net benefits and exhibited a wider range of threshold probabilities for the prediction of therapeutic effects.

CONCLUSION

Our study suggests that the nomogram model, including baseline Tinnitus Handicapped Inventory score and treatment duration, could achieve optimal performance in the preoperative prediction of the therapeutic effect of modified tinnitus-relieving sound.

Neuroprotection Role of Vitamin C by Upregulating Glutamate Transporter-1 in Auditory Cortex of Noise-Induced Tinnitus Animal Model

Vitamin C (Vc) plays a pivotal role in a series of pathological processes, such as tumors, immune diseases, and neurological disorders. However, its therapeutic potential for tinnitus management remains unclear. In this study, we find that Vc relieves tinnitus in noise-exposed rats. In the 7-day therapy groups, spontaneous firing rate (SFR) increases from 1.17 ± 0.10 Hz to 1.77 ± 0.15 Hz after noise exposure. Vc effectively reduces the elevated SFR to 0.99 ± 0.07 and 0.55 ± 0.05 Hz at different doses. The glutamate level in auditory cortex of noise-exposed rats (3.78 ± 0.42 μM) increases relative to that in the control group (1.34 ± 0.22 μM). High doses of Vc (500 mg/kg/day) effectively reduce the elevated glutamate levels (1.49 ± 0.28 μM). Mechanistic studies show that the expression of glutamate transporter 1 (GLT-1) is impaired following noise exposure and that Vc treatment effectively restores GLT-1 expression in the auditory cortex. Meanwhile, the GLT-1 inhibitor, dl-threo-beta-benzyloxyaspartic acid (dl-TBOA), invalidates the protection role of Vc. Our finding shows that Vc substantially enhances glutamate clearance by upregulating GLT-1 and consequently alleviates noise-induced tinnitus. This study provides valuable insight into a novel biological target for the development of therapeutic interventions that may prevent the onset of tinnitus.

Left prefrontal intermittent theta burst stimulation ameliorates tinnitus distress and symptoms of depression - A feasibility study

Tinnitus remains a notoriously difficult to treat clinical entity. 1-2% of the entire population report relevant emotional distress due to tinnitus, and causal treatments are lacking. Repetitive transcranial magnetic stimulation (rTMS), most commonly of auditory cortical areas, has shown mixed results in the past. Prefrontal rTMS, including intermittent theta burst stimulation (iTBS) has shown more promising results in the treatment of depression, and clinical data suggests a meaningful overlap between tinnitus and depression. Therefore, we performed a feasibility study of 28 consecutive patients with tinnitus treated with an iTBS protocol over the left dorsolateral prefrontal cortex for three weeks. After treatment, we observed significant ameliorations of tinnitus distress as measured by the Tinnitus Handicap Inventory Questionnaire (THI), the Tinnitus Functional Index (TFI), the Mini-Tinnitus Questionnaire (Mini-TQ) and also of depression as measured by the Major Depression Inventory (MDI). Effect sizes were small to moderate and short-lived. Treatment response rates, defined as improvement of the THI of at least 7 points, were 35.7%. At follow-up twelve weeks after end of treatment, severity of tinnitus and depression returned to approximately baseline level on a descriptive level. Amelioration of depressive symptoms correlated only with TFI change, but not that of other measures of tinnitus distress. The data suggest that a prefrontal iTBS protocol might be applied in the treatment of tinnitus and open avenues for future neurostimulatory treatments other than those of auditory regions.

Focal tDCS of auditory cortex in chronic tinnitus: A randomized controlled mechanistic trial

OBJECTIVE

The goal of this pilot study was to understand how focal transcranial direct current stimulation (tDCS) targeting auditory cortex changes brain function in chronic tinnitus using magnetic resonance imaging (MRI).

METHODS

People with chronic tinnitus were randomized to active or sham tDCS on five consecutive days in this mechanistic trial (n = 10/group). Focal 4x1 tDCS (central anode, surround cathodes) targeted left auditory cortex, with single-blind 2 mA current during twenty-minute sessions. Arterial spin-labeled and blood oxygenation level dependent MRI occurred immediately before and after the first tDCS session, and tinnitus symptoms were measured starting one week before the first tDCS session and through four weeks after the final session.

RESULTS

Acute increases in cerebral blood flow and functional connectivity were noted in auditory cortex after the first active tDCS session. Reduced tinnitus loudness ratings after the final tDCS session correlated with acute change in functional connectivity between an auditory network and mediodorsal thalamus and prefrontal cortex. Reduced tinnitus intrusiveness also correlated with acute change in connectivity between precuneus and an auditory network.

CONCLUSIONS

Focal auditory-cortex tDCS can influence function in thalamus, auditory, and prefrontal cortex, which may associate with improved tinnitus.

SIGNIFICANCE

With future refinement, tDCS targeting auditory cortex could become a viable intervention for tinnitus.

A Systematic Review on the Genetic Contribution to Tinnitus

PURPOSE

To assess the available evidence to support a genetic contribution and define the role of common and rare variants in tinnitus.

METHODS

After a systematic search and quality assessment, 31 records including 383,063 patients were selected (14 epidemiological studies and 17 genetic association studies). General information on the sample size, age, sex, tinnitus prevalence, severe tinnitus distribution, and sensorineural hearing loss was retrieved. Studies that did not include data on hearing assessment were excluded. Relative frequencies were used for qualitative variables to compare different studies and to obtain average values. Genetic variants and genes were listed and clustered according to their potential role in tinnitus development.

RESULTS

The average prevalence of tinnitus estimated from population-based studies was 26.3% for any tinnitus, and 20% of patients with tinnitus reported it as an annoying symptom. One study has reported population-specific differences in the prevalence of tinnitus, the white ancestry being the population with a higher prevalence. Genome-wide association studies have identified and replicated two common variants in the Chinese population (rs2846071; rs4149577) in the intron of TNFRSF1A, associated with noise-induced tinnitus. Moreover, gene burden analyses in sequencing data from Spanish and Swede patients with severe tinnitus have identified and replicated ANK2, AKAP9, and TSC2 genes.

CONCLUSIONS

The genetic contribution to tinnitus is starting to be revealed and it shows population-specific effects in European and Asian populations. The common allelic variants associated with tinnitus that showed replication are associated with noise-induced tinnitus. Although severe tinnitus has been associated with rare variants with large effect, their role on hearing or hyperacusis has not been established.

The effect of MemoVigor 2 on recent-onset idiopathic tinnitus: a randomized double-blind placebo-controlled clinical trial

Background: Tinnitus is a common symptom associated with the conscious perception of sound in the absence of a corresponding external or internal sound source, which can severely impact quality of life. Because of the current limited understanding of the precise pathophysiological mechanism of idiopathic tinnitus, no curable treatment has been attained yet. A food supplement trading as MemoVigor 2, which contains a combination of therapeutic ingredients with mainly antioxidant activity, has been used in the treatment of tinnitus. The objective of our study was to evaluate the effectiveness of MemoVigor 2 in the treatment of recent-onset idiopathic tinnitus. Methods: In a prospective single-centre randomized, double-blind, placebo-controlled clinical trial we studied 204 patients with idiopathic tinnitus divided into two groups: 104 patients who received MemoVigor 2 and 100 patients treated with placebo. To evaluate changes in tinnitus we used (1) audiometry/tympanometry; (2) specific measures of tinnitus perception, including tinnitus pitch, loudness at tinnitus pitch, loudness at 1 kHz, minimum masking level, and residual inhibition; (3) questionnaires of tinnitus handicap inventory, mini tinnitus questionnaire and patients' global impression of change. All patients underwent this test battery at the beginning of the study and in a repeat post-3-month session. Results: All tinnitus measures, including pitch, loudness, minimum masking level and residual inhibition improved significantly in the intervention group. Most of these measures improved in the placebo group too, but in a lesser degree. All questionnaire scores diminished significantly in both groups, but the degree of decrease was greater in the intervention group. The participants' tinnitus outcome reported after treatment using the patients' global impression of change score differed significantly between the two groups, with greater improvement observed in the intervention group. Conclusion: We found that the use of MemoVigor 2 improved recent-onset tinnitus, as proved by a set of tests performed for its evaluation, including audiometric measures, specific measures of tinnitus perception and tinnitus questionnaires. Tinnitus in the placebo group improved too, but to a lesser degree. Clinical Trial Registration: isrctn.com, Identifier ISRCTN16025480.

The long-term effect of modulated acoustic stimulation on alteration in EEG brain network of chronic tinnitus patients: An exploratory study

Acoustic stimulation is one of the most influential techniques for distressing tinnitus, while how it functions to reverse neural changes associated with tinnitus remains undisclosed. In this study, our objective is to investigate alterations in brain networks to shed light on the enigma of acoustic intervention for tinnitus. We designed a 75-day long-term acoustic intervention experiment, during which chronic tinnitus patients received daily modulated acoustic stimulation with each session lasting 15 days. Every 15 days, professional tinnitus assessments were conducted, collecting both electroencephalogram (EEG) and tinnitus handicap inventory (THI) data from the patients. Thereafter, we investigated the changes in EEG network organizations during continuous acoustic stimulation and their progressive evolution throughout long-term therapy, alongside exploring the associations between the evolving changes of the network alterations and THI. Our current study findings reveal reorganization in alpha/beta long-range frontal-parietal-occipital connections as well as local frontal and parietal-occipital regions induced by acoustic stimulation. Furthermore, we observed a decrease in modulation effects as therapy sessions progressed. These alterations in brain networks reflect the reversal of tinnitus-related neural activities, particularly distress and perception; thus contributing to tinnitus rehabilitation through long-term modulation effects. This study provides unique insights into how long-term acoustic intervention affects the network organizations of tinnitus patients and deepens our understanding of the pathophysiological mechanisms underlying tinnitus rehabilitation.

Screening for Circulating Inflammatory Proteins Does Not Reveal Plasma Biomarkers of Constant Tinnitus

BACKGROUND AND OBJECTIVE

Tinnitus would benefit from an objective biomarker. The goal of this study is to identify plasma biomarkers of constant and chronic tinnitus among selected circulating inflammatory proteins.

METHODS

A case-control retrospective study on 548 cases with constant tinnitus and 548 matched controls from the Swedish Tinnitus Outreach Project (STOP), whose plasma samples were examined using Olink's Inflammatory panel. Replication and meta-analysis were performed using the same method on samples from the TwinsUK cohort. Participants from LifeGene, whose blood was collected in Stockholm and Umeå, were recruited to STOP for a tinnitus subtyping study. An age and sex matching was performed at the individual level. TwinsUK participants (n = 928) were selected based on self-reported tinnitus status over 2 to 10 years. Primary outcomes include normalized levels for 96 circulating proteins, which were used as an index test. No reference standard was available in this study.

RESULTS

After adjustment for age, sex, BMI, smoking, hearing loss, and laboratory site, the top proteins identified were FGF-21, MCP4, GDNF, CXCL9, and MCP-1; however, these were no longer statistically significant after correction for multiple testing. Stratification by sex did not yield any significant associations. Similarly, associations with hearing loss or other tinnitus-related comorbidities such as stress, anxiety, depression, hyperacusis, temporomandibular joint disorders, and headache did not yield any significant associations. Analysis in the TwinsUK failed in replicating the top candidates. Meta-analysis of STOP and TwinsUK did not reveal any significant association. Using elastic net regularization, models exhibited poor predictive capacity tinnitus based on inflammatory markers [sensitivity = 0.52 (95% CI 0.47-0.57), specificity = 0.53 (0.48-0.58), positive predictive value = 0.52 (0.47-0.56), negative predictive values = 0.53 (0.49-0.58), and AUC = 0.53 (0.49-0.56)].

DISCUSSION

Our results did not identify significant associations of the selected inflammatory proteins with constant tinnitus. Future studies examining longitudinal relations among those with more severe tinnitus and using more recent expanded proteomics platforms and sampling of cerebrospinal fluid could increase the likelihood of identifying relevant molecular biomarkers.

Noise-Induced Hearing Loss Alters Potassium-Chloride CoTransporter KCC2 and GABA Inhibition in the auditory centers

Homeostatic plasticity, the ability of neurons to maintain their averaged activity constant around a set point value, is thought to account for the central hyperactivity after hearing loss. Here, we investigated the putative role of GABAergic neurotransmission in this mechanism after a noise-induced hearing loss larger than 50 dB in high frequencies in guinea pigs. The effect of GABAergic inhibition is linked to the normal functioning of K+-Cl- co-transporter isoform 2 (KCC2) which maintains a low intracellular concentration of chloride. The expression of membrane KCC2 were investigated before after noise trauma in the ventral and dorsal cochlear nucleus (VCN and DCN, respectively) and in the inferior colliculus (IC). Moreover, the effect of gabazine (GBZ), a GABA antagonist, was also studied on the neural activity in IC. We show that KCC2 is downregulated in VCN, DCN and IC 3 days after noise trauma, and in DCN and IC 30 days after the trauma. As expected, GBZ application in the IC of control animals resulted in an increase of spontaneous and stimulus-evoked activity. In the noise exposed animals, on the other hand, GBZ application decreased the stimulus-evoked activity in IC neurons. The functional implications of these central changes are discussed.

Nuances in intensity deviant asymmetric responses as a biomarker for tinnitus

We attempted to replicate a potential tinnitus biomarker in humans based on the Sensory Precision Integrative Model of Tinnitus called the Intensity Mismatch Asymmetry. A few advances on the design were also included, including tighter matching of participants for gender, and a control stimulus frequency of 1 kHz to investigate whether any differences between control and tinnitus groups are specific to the tinnitus frequency or domain-general. The expectation was that there would be asymmetry in the MMN responses between tinnitus and control groups at the tinnitus frequency, but not at the control frequency, where the tinnitus group would have larger, more negative responses to upward deviants than downward deviants, and the control group would have the opposite pattern or lack of a deviant direction effect. However, no significant group differences were found. There was a striking difference in response amplitude to control frequency stimuli compared to tinnitus frequency stimuli, which could be an intrinsic quality of responses to these frequencies or could reflect high frequency hearing loss in the sample. Additionally, the upward deviants elicited stronger MMN responses in both groups at tinnitus frequency, but not at the control frequency. Factors contributing to these discrepant results at the tinnitus frequency could include hyperacusis, attention, and wider contextual effects of other frequencies used in the experiment (i.e. the control frequency in other blocks).

Management of Migraine-Associated Vestibulocochlear Disorders

Migraine is a chronic neurological disorder that frequently coexists with different vestibular and cochlear symptoms (sudden hearing loss, tinnitus, otalgia, aural fullness, hyperacusis, dizziness, imbalance, and vertigo) and disorders (recurrent benign positional vertigo, persistent postural perceptual dizziness, mal de debarquement, and Menière's disease). Despite evidence of an epidemiological association and similar pathophysiology between migraine and these vestibulocochlear disorders, patients suffering from migraine-related symptoms are usually underdiagnosed and undertreated. Current migraine treatment options have shown success in treating vestibulocochlear symptoms. Lifestyle and dietary modifications (reducing stress, restful sleep, avoiding migraine dietary triggers, and avoiding starvation and dehydration) and supplements (vitamin B2 and magnesium) offer effective first-line treatments. Treatment with migraine prophylactic medications such as tricyclic antidepressants (e.g., nortriptyline), anticonvulsants (e.g., topiramate), and calcium channel blockers (e.g., verapamil) is implemented when lifestyle and dietary modifications are not sufficient in improving a patient's symptoms. We have included an algorithm that outlines a suggested approach for addressing these symptoms, taking into account our clinical observations. Greater recognition and understanding of migraine and its related vestibular and cochlear symptoms are needed to ensure the appropriate diagnosis and treatment of affected patients.

Focal transcranial direct current stimulation of auditory cortex in chronic tinnitus: A randomized controlled mechanistic trial

Objective

The goal of this pilot MRI study was to understand how focal transcranial direct current stimulation (tDCS) targeting auditory cortex changes brain function in chronic tinnitus.

Methods

People with chronic tinnitus were randomized to active or sham tDCS on five consecutive days in this pilot mechanistic trial (n=10/group). Focal 4×1 tDCS (central anode, surround cathodes) targeted left auditory cortex, with single-blind 2mA current during twenty-minute sessions. Arterial spin-labeled and blood oxygenation level dependent MRI occurred immediately before and after the first tDCS session, and tinnitus symptoms were measured starting one week before the first tDCS session and through four weeks after the final session.

Results

Acute increases in cerebral blood flow and functional connectivity were noted in auditory cortex after the first active tDCS session. Reduced tinnitus loudness ratings after the final tDCS session correlated with acute change in functional connectivity between an auditory network and mediodorsal thalamus and prefrontal cortex. Reduced tinnitus intrusiveness also correlated with acute change in connectivity between precuneus and an auditory network.

Conclusions

Focal auditory-cortex tDCS can influence function in thalamus, auditory, and prefrontal cortex, which may associate with improved tinnitus.

Significance

With future refinement, noninvasive brain stimulation targeting auditory cortex could become a viable intervention for tinnitus.

Desensitizing nicotinic agents normalize tinnitus-related inhibitory dysfunction in the auditory cortex and ameliorate behavioral evidence of tinnitus

Tinnitus impacts between 10-20% of the population. Individuals most troubled by their tinnitus have their attention bound to and are distracted by, their tinnitus percept. While numerous treatments to ameliorate tinnitus have been tried, no therapeutic approach has been clinically accepted. The present study used an established condition-suppression noise-exposure rat model of tinnitus to: (1) examine tinnitus-related changes in nAChR function of layer 5 pyramidal (PNs) and of vasoactive intestinal peptide (VIP) neurons in primary auditory cortex (A1) and (2) examine how the partial desensitizing nAChR agonists, sazetidine-A and varenicline, can act as potential therapeutic agents in the treatment of tinnitus. We posited that tinnitus-related changes in layer 5 nAChR responses may underpin the decline in attentional resources previously observed in this animal model (Brozoski et al., 2019). In vitro whole-cell patch-clamp studies previously revealed a significant tinnitus-related loss in nAChR-evoked excitatory postsynaptic currents from A1 layer 5 PNs. In contrast, VIP neurons from animals with behavioral evidence of tinnitus showed significantly increased nAChR-evoked excitability. Here we hypothesize that sazetidine-A and varenicline have therapeutic benefits for subjects who cannot divert their attention away from the phantom sound in their heads. We found that sazetidine-A or varenicline normalized tinnitus-related reductions in GABAergic input currents onto A1 layer 5 PNs. We then tested sazetidine-A and varenicline for the management of tinnitus using our tinnitus animal model. Subcutaneous injection of sazetidine-A or varenicline, 1 h prior to tinnitus testing, significantly decreased the rat's behavioral evidence of tinnitus in a dose-dependent manner. Collectively, these results support the need for additional clinical investigations of partial desensitizing nAChR agonists sazetidine-A and varenicline for the treatment of tinnitus.

Clinical characteristics and psychoacoustic analysis of acute and chronic subjective tinnitus

Objective

This study aimed to understand the demographics, clinical characteristics, and psychoacoustic status of subjective tinnitus patients to explore the factors associated with acute and chronic tinnitus in the general hospitals of Shanghai.

Methods

A cross-sectional study was conducted to investigate the clinical characteristics and psychoacoustic status of subjective tinnitus patients with history greater than 1 month. Data were collected during January 2021 and January 2022 from eight general hospitals in five districts of Shanghai, China. All patients accepted questionnaires and acoustic examination, then SPSS 22.0 and GraphPad Prism 8.0.2 were applied for data analysis.

Results

Among the 359 tinnitus patients, 126 cases were diagnosed with acute tinnitus, 58 cases were subacute tinnitus, and 175 cases were chronic tinnitus. Patients with acute and chronic tinnitus differed in terms of side of tinnitus, hearing loss, frequency of tinnitus, severity of tinnitus, anxiety, depression, and sleep status. Different characteristics were included in the multivariate ordinal logistic regression analysis. Persistent tinnitus (OR = 2.00, p = .008), high frequency hearing loss (OR = 4.77, p < .001), depression (OR = 1.23, p < .001) were found to be positively associated with the course of tinnitus. Unilateral tinnitus (OR = 0.48, p = .003), mild (OR = 0.29, p = .001) and moderate (OR = 0.46, p = .038) hearing loss, VAS scores (OR = 0.82, p = .032), anxiety (OR = 0.81, p < .001), THI scores (OR = 0.98, p = .002), and sleep disorders (OR = 0.94, p = .025) were found to be negatively associated with the course of tinnitus.

Conclusion

Patients with acute tinnitus were at greater risk for anxiety, sleep disturbances, and exacerbation of tinnitus perception, and those with chronic tinnitus were at greater risk for depression.

Lay Summary

Our study demonstrated that patients with acute tinnitus were at greater risk for anxiety, sleep disturbances, and exacerbation of tinnitus perception, and those with chronic tinnitus were at greater risk for depression.

The Comorbidity of Depression and Anxiety Symptoms in Tinnitus Sufferers: A Network Analysis

OBJECTIVE

Sufferers of tinnitus, especially of the prolonged type, frequently suffer from comorbid depression and anxiety. From the perspective of the network model, this comorbidity is thought to be an interacting system of these two symptoms. In our study, we conducted a network analysis of depression and anxiety comorbidity in tinnitus sufferers, aiming to identify the central and bridge symptoms and make informed suggestions for clinical interventions and psychotherapy.

METHOD

A total of 566 tinnitus sufferers were enrolled in our study. The Patient Health Questionnaire-9 (PHQ-9) and the Generalized Anxiety Disorder 7-Item Questionnaire (GAD-7) were selected to evaluate depression and anxiety symptoms, respectively, followed by network analysis to construct the interacting networks.

RESULTS

The findings identified six edges of strongest regularized partial correlations in this network. Of these, three were depression symptoms and three were anxiety symptoms. The anxiety symptoms "Unable to control worry" and "Relaxation difficulty" and the depression symptom "Feeling depressed or hopeless" had the highest expected influence centrality. The analysis results also revealed three bridge symptoms: "Afraid something awful might happen", "Feeling of worthlessness", and "Trouble concentrating". As for "Suicidal ideation", the direct relations between this symptom and "Afraid something awful might happen" and "Feeling depressed or hopeless" were the strongest.

CONCLUSIONS

The central and bridge symptoms of the interacting network of depression and anxiety symptoms in tinnitus sufferers can be considered a significant transdiagnostic intervention target for the management of this comorbidity. In particular, clinical prevention and psychotherapy should be implemented, targeting the symptoms that have the strongest associations with suicidal ideation.

The α9α10 acetylcholine receptor: a non-neuronal nicotinic receptor

Within the superfamily of pentameric ligand-gated ion channels, cholinergic nicotinic receptors (nAChRs) were classically identified to mediate synaptic transmission in the nervous system and the neuromuscular junction. The α9 and α10 nAChR subunits were the last ones to be identified. Surprisingly, they do not fall into the dichotomic neuronal/muscle classification of nAChRs. They assemble into heteropentamers with a well-established function as canonical ion channels in inner ear hair cells, where they mediate central nervous system control of auditory and vestibular sensory processing. The present review includes expression, pharmacological, structure-function, molecular evolution and pathophysiological studies, that define receptors composed from α9 and α10 subunits as distant and distinct members within the nAChR family. Thus, although α9 and α10 were initially included within the neuronal subdivision of nAChR subunits, they form a distinct clade within the phylogeny of nAChRs. Following the classification of nAChR subunits based on their main synaptic site of action, α9 and α10 should receive a name in their own right.

Tinnitus and treatment-resistant depression

Tinnitus, a frequent disorder, is the conscious perception of a sound in the absence of a corresponding external acoustic sound source in the sense of a phantom sound. Although the majority of people who perceive a tinnitus sound can cope with it and are only minimaly impaired in their quality of lfe, 2-3% of the population perceive tinnitus as a major problem. Recently it has been proposed that the two groups should be differentiated by distict terms: "Tinnitus" describes the auditory or sensory component, whereas "Tinnitus Disorder" reflects the auditory component and the associated suffering. There is overwhelming evidence that a high tinnitus burden is associated with the increased occurrence of comorbidities, including depression. Since no causal therapeutic options are available for patients with tinnitus at the present time, the identification and adequate treatment of relevant comorbidities is of great importance for the reduction of tinnitus distress. This chapter deals with the relationship between tinnitus and depression. The neuronal mechanisms underlying tinnitus will first be discussed. There will also be an overview about depression and treatment resistant depression (TRD). A comprehensive review about the state-of-the-art evidences of the relationship between tinnitus and TRD will then be provided.

Is There an Optimal Repetitive Transcranial Magnetic Stimulation Target to Treat Chronic Tinnitus?

OBJECTIVE

Chronic tinnitus is a clinical symptom that affects 10% to 15% of the adult population. Repetitive transcranial magnetic stimulation (rTMS) is a promising treatment, but significant heterogeneity exists in the treatment outcomes and stimulation parameters. In this study, we perform a qualitative systematic review to determine if there is an optimal rTMS site to treat tinnitus.

DATA SOURCES

A literature search was performed by searching the MEDLINE, Embase, Web of Science, and Cochrane databases.

REVIEW METHODS

Sham-controlled studies in adults were included that contained >10 patients with tinnitus for >3 months and utilized 10 to 20 electroencephalography coordinates. Study outcomes were considered positive if the treatment arm reported a significant reduction in the primary tinnitus score relative to sham.

RESULTS

There were 1211 studies screened. Nineteen studies met the inclusion criteria, and 8 unique stimulation sites were reported. Studies had 53.7 ± 46.0 patients (mean ± SD). The mean duration of follow-up was 10.3 ± 9.6 weeks. Positive outcomes regarding tinnitus suppression were reported in 5 of 5 (100%) studies stimulating the temporoparietal junction midway between T3 and P3 or between T4 and P4. Tinnitus suppression at all other sites was less frequent with a combined success rate of only 8 of 14 (57.1%).

CONCLUSION

Significant heterogeneity exists in the literature in regard to the optimal transcranial magnetic stimulation target. These preliminary findings suggest that the temporoparietal junction midway between T3 and P3 or T4 and P4 is a promising nonauditory rTMS target in the setting of chronic tinnitus. Future research should elucidate the effectiveness of this site for tinnitus suppression.

[Tinnitus]

Tinnitus is a highly prevalent symptom and a common reason for seeing an otolaryngologist. Since tinnitus can go hand in hand with hearing loss, the step-by-step clarification of hearing loss is one of the essential ENT examinations for tinnitus sufferers. The anamnesis and medical history are relevant, since a multidimensional interaction with the tinnitus can be important for the treatment, especially in the case of a psychological comorbidity. In the vast majority of patients, no causal factor can be found. In the absence of external stimuli, phantom perceptions of tones or noises are held responsible for subjective tinnitus, which probably arises from pathological changes of the auditory pathway, but also in non-auditory cortical structures. In the case of acute tinnitus, a comprehensive audiological assessment is needed, and if the hearing threshold is normal, counseling is the priority. The patient must be informed about the nature of these benign symptoms. So far, there is no acute therapy that has been proven to increase the probability of healing, i.e. the disappearance of the acute tinnitus. Only if the hearing threshold descended, for instance in case of sudden idiopathic hearing loss, therapy of the underlying disease can also lead to improvement or healing of the acute tinnitus. Counseling for chronic tinnitus with high burden is also about reducing exaggerated expectations of healing that cannot be fulfilled. The training of habituation strategies is important. The standard of therapy for chronic tinnitus with psychological strain represents cognitive behavioral therapy for dealing with the tinnitus in a beneficial way. Tinnitus is a symptom of a very heterogeneous group of patients. In the future, it is to be hoped that digital applications and interventions in particular will be evaluated in quality-controlled clinical studies in order to be able to further personalize patient therapy.

Herbal medicines in the treatment of tinnitus: An updated review

Tinnitus is perception of sound in the absence of an apparent external acoustic stimulus. The condition is prevalent in adults, especially the elderly (≥65 years), and may be associated with cognitive function decline and significantly impacts on the quality of life, heralding difficulties in managing this challenging disorder. Interventions for tinnitus have been varied. However, drugs have not yet been approved for the treatment of tinnitus and there is no pharmacotherapy recommended by existing guidelines. Still, herbal medicines are used for the treatment of tinnitus in many countries, especially Gingko (G.) biloba. In the current updated literature review, we evaluated the efficacy of herbal medicines in the treatment of tinnitus by reviewing the evidence of relevant randomized controlled trials. The authors also highlight some of the issues in clinical trials of herbal medicines given that currently available evidence on herbal medicines for tinnitus is overall of insufficient quality and the conclusions from existing trials are conflicting. Nevertheless, there is a clear and urgent need for safe and effective pharmacotherapy of tinnitus.

Evaluation and Management of Tinnitus: Are There Opportunities for Improvement?

OBJECTIVE

To review current information about diagnosis and management of tinnitus aiming to identify opportunities for achieving a cost-effective, efficient, evidence-based approach that meets the needs of tinnitus sufferers.

DATA SOURCES

PubMed/MEDLINE.

REVIEW METHODS

In total, 249 relevant published reports were reviewed. Pertinent keywords and MeSH terms identified reports via PubMed and EMBASE. Acknowledged experts were consulted on ways to improve tinnitus management.

CONCLUSIONS

There may be opportunities to improve evaluation and management of patients with tinnitus using modern modes of communication and a multidisciplinary therapeutic approach.

IMPLICATIONS FOR PRACTICE

Tinnitus can adversely affect quality of life while being time-consuming and costly to evaluate and manage. Based on both personal experience and the reports of others, patients with tinnitus who choose to see a physician primarily want to know two things: (1) that the tinnitus that is so distressing will not remain at the same level of severity forever and (2) that something can be done to help cope with the tinnitus that is so annoying. Recent advancements in internet communications, social media, information technology, artificial intelligence, machine learning, holistic medical care, mind-body integrative health care, and multidisciplinary approaches in medical therapeutics may be possibly making new ways of meeting the needs of patients with tinnitus.

Effects of acupuncture on the outcome of tinnitus: An overview of systematic reviews

BACKGROUND

To systematically summarize the evidence for the efficacy of acupuncture in tinnitus treatment, we assessed the methodological quality, reporting quality, and evidence quality of systematic reviews/meta-analyses (SRs/MAs) of acupuncture in the treatment of tinnitus.

METHODS

From inception to March 2022, we conducted a detailed and comprehensive search of eight electronic databases in Chinese and English. The Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR-2), the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) were used to assess methodological quality, reporting quality and evidence quality for inclusion in SRs/MAs, respectively.

RESULTS

Fourteen published SRs/MAs met the inclusion criteria and were included in the study. Eleven studies reported that acupuncture was effective in treating tinnitus, and three studies reported that no firm conclusions could be drawn about the effectiveness of acupuncture in treating tinnitus. The results of the AMSTAR-2 assessment showed that the methodological quality of the included studies was relatively low in general, with one being moderate quality and the rest being very low quality. The PRISMA checklist evaluation results showed that no studies fully report checklists, with protocol registration and search strategies being the main reporting weaknesses. The GRADE assessment showed that no results were high-quality evidence, 17 results were moderate-quality evidence, 25 results were low-quality evidence, and 12 results were very low-quality evidence.

CONCLUSION

Acupuncture seems to be a positive and effective treatment for tinnitus. However, the methodological quality and quality of evidence for SRs/MAs in the included studies were generally low, and this result must be viewed with caution. Therefore, more high-quality, large-scale, multi-center randomized controlled trials are needed in the future to verify the effectiveness of acupuncture in the treatment of tinnitus.

Changes in late-latency auditory evoked potentials after tinnitus suppression using auditory stimulation

OBJECTIVE

Tinnitus can result from auditory system reorganization due to neural activity dysfunctions. Auditory stimulation can cause temporary or persistent tinnitus alleviation by altering the neural generators. The present study investigated the changes in Late-Latency Auditory Evoked Potentials (LLAEPs) after tinnitus suppression using auditory stimulation with short-term Residual Inhibition (RI) and long-term Tinnitus Masker (TM).

METHODS

The study included 40 participates with equal numbers in the Tinnitus Group (TG), including the chronic tinnitus subjects, and the Control Group (CG), including matched volunteers. The participants had normal hearing in conventional audiometry. All the participants underwent LLAEP recording pre-intervention and after a one-minute auditory stimulation (RI), as well as a pre-intervention Dichotic Digit Test (DDT) as a behavioral assessment of the selective attention. Moreover, TG underwent a 3-month course of TM, a third LLAEP recording post-TM, a second DDT post-TM, and the Tinnitus Handicap Inventory (THI) before and after the TM.

RESULTS

In the baseline LLAEP recording, the TG had significantly later N1, P3a, and P3b latencies, as well as significantly lower P3a and P3b amplitudes. The second LLAEP recording showed a significant intragroup increase in P3a amplitude and a significant decrease in P3a latency in the TG, while no significant intragroup difference was observed in the CG. In the third LLAEP recording performed on TG, the P3a amplitude and latency had significant changes compared to the second recording, while the N1 latency was significantly decreased. Moreover, the DDT and THI scores had significant improvement after the TM in TG.

CONCLUSIONS

The present study showed the neurophysiological changes after short-term (RI) and long-term (TM) auditory stimulations in tinnitus subjects. The LLAEP changes suggest that these interventions lead to tinnitus suppression through common mechanisms. The electrophysiological observation was also confirmed using behavioral assessments.

LEVEL OF EVIDENCE

This study type is a "comparative study" with the level of evidence "3".

The Fudan Tinnitus Relieving System (FTRS): The initial results of a smartphone application for tinnitus management and treatment

OBJECTIVE

Tinnitus is highly prevalent in the population, but there are currently few effective therapeutic interventions. Mobile applications (apps) might be helpful in tinnitus diagnosis and treatment by offering sound or music tools as well as questionnaires. We assessed the efficacy of a free, publicly available smartphone app (Fudan Tinnitus Relieving System, FTRS) for self-management of tinnitus and related symptoms.

METHODS

Among a total of 3564 participants recruited primarily online, 2744 patients had complete information at baseline and were an average of 37 years old and were 59.84 % male. Web-administered self-report measures THI, HADS, AIS, and other multi-dimensional scales were conducted at baseline and at 1 month and 2 months following treatment. Data from 54 participants who completed continuous follow-up were used for the final efficacy analysis and longitudinal analysis.

RESULTS

Following the intent-to-treat principle, t-tests revealed that the distribution of patients and the tinnitus features of patients of different genders were heterogeneous. One-way ANOVA showed that after using the FTRS app, THI scores showed a decreasing trend (p < 0.001).

CONCLUSION

FTRS use resulted in significantly greater improvements in tinnitus and other outcomes relative to their baseline condition before treatment. Given the ubiquity of smartphones, FTRS may provide a wide-reaching and convenient public health intervention for individuals with tinnitus symptoms.

Hearing loss drug discovery and medicinal chemistry: Current status, challenges, and opportunities

Hearing loss is a severe high unmet need condition affecting more than 1.5 billion people globally. There are no licensed medicines for the prevention, treatment or restoration of hearing. Prosthetic devices, such as hearing aids and cochlear implants, do not restore natural hearing and users struggle with speech in the presence of background noise. Hearing loss drug discovery is immature, and small molecule approaches include repurposing existing drugs, combination therapeutics, late-stage discovery optimisation of known chemotypes for identified molecular targets of interest, phenotypic tissue screening and high-throughput cell-based screening. Hearing loss drug discovery requires the integration of specialist therapeutic area biology and otology clinical expertise. Small molecule drug discovery projects in the global clinical portfolio for hearing loss are here collated and reviewed. An overview is provided of human hearing, inner ear anatomy, inner ear delivery, types of hearing loss and hearing measurement. Small molecule experimental drugs in clinical development for hearing loss are reviewed, including their underpinning biology, discovery strategy and activities, medicinal chemistry, calculated physicochemical properties, pharmacokinetics and clinical trial status. SwissADME BOILED-Egg permeability modelling is applied to the molecules reviewed, and these results are considered. Non-small molecule hearing loss assets in clinical development are briefly noted in this review. Future opportunities in hearing loss drug discovery for human genomics and targeted protein degradation are highlighted.

Higher Peripheral Inflammation Is Associated With Lower Orbitofrontal Gamma Power in Chronic Tinnitus

Chronic tinnitus, the continuous perception of a phantom sound, is a highly prevalent audiological symptom, for which the underlying pathology has not yet been fully understood. It is associated with neurophysiological alterations in the central nervous system and chronic stress, which can be related with a disinhibition of the inflammatory system. We here investigated the association between resting-state oscillatory activity assessed with Magnetoencephalography (MEG), and peripheral inflammation assessed by C-reactive protein (CRP) in a group of patients with chronic tinnitus (N = 21, nine males, mean age: 40.6 ± 14.6 years). Additionally, CRP was assessed in an age- and sex-matched healthy control group (N = 21, nine males, mean age: 40.9 ± 15.2 years). No MEG data was available for the control group. We found a significant negative correlation between CRP and gamma power in the orbitofrontal cortex in tinnitus patients (p < 0.001), pointing to a deactivation of the orbitofrontal cortex when CRP was high. No significant clusters were found for other frequency bands. Moreover, CRP levels were significantly higher in the tinnitus group than in the healthy controls (p = 0.045). Our results can be interpreted based on findings from previous studies having disclosed the orbitofrontal cortex as part of the tinnitus distress network. We suggest that higher CRP levels and the associated deactivation of the orbitofrontal cortex in chronic tinnitus patients is maintaining the tinnitus percept through disinhibition of the auditory cortex and attentional or emotional top-down processes. Although the direction of the association (i.e., causation) between CRP levels and orbitofrontal gamma power in chronic tinnitus is not yet known, inflammation reducing interventions are promising candidates when developing treatments for tinnitus patients. Overall, our study highlights the importance of considering immune-brain communication in tinnitus research.

The α9α10 nicotinic acetylcholine receptor: a compelling drug target for hearing loss?

INTRODUCTION

Hearing loss is a major health problem, impacting education, communication, interpersonal relationships, and mental health. Drugs that prevent or restore hearing are lacking and hence novel drug targets are sought. There is the possibility of targeting the α9α10 nicotinic acetylcholine receptor (nAChR) in the prevention of noise-induced, hidden hearing loss and presbycusis. This receptor mediates synaptic transmission between medial olivocochlear efferent fibers and cochlear outer hair cells. This target is key since enhanced olivocochlear activity prevents noise-induced hearing loss and delays presbycusis.

AREAS COVERED

The work examines the α9α10 nicotinic acetylcholine receptor (nAChR), its role in noise-induced, hidden hearing loss and presbycusis and the possibility of targeting. Data has been searched in Pubmed, the World Report on Hearing from the World Health Organization and the Global Burden of Disease Study 2019.

EXPERT OPINION

The design of positive allosteric modulators of α9α10 nAChRs is proposed because of the advantage of reinforcing the medial olivocochlear (MOC)-hair cell endogenous neurotransmission without directly stimulating the target receptors, therefore avoiding receptor desensitization and reduced efficacy. The time is right for the discovery and development of α9α10 nAChRs targeting agents and high throughput screening assays will support this.

The effectiveness of the combined transcranial direct current stimulation (tDCS) and tailor-made notched music training (TMNMT) on psychoacoustic, psychometric, and cognitive indices of tinnitus patients

PURPOSE

Tinnitus network(s) consists of pathways in the auditory cortex, frontal cortex, and the limbic system. The cortical hyperactivity caused by tinnitus may be suppressed by neuromodulation techniques. Due to the lack of definitive treatment for tinnitus and limited usefulness of the individual methods, in this study, a combination of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) and tailor-made notched music training (TMNMT) was used.

MATERIAL AND METHODS

In this descriptive-analytic study, 26 patients with chronic unilateral tinnitus of the right ear were randomly divided into the clinical trial group (CTG) and the control group (CG). In both groups, six sessions of tDCS with 2 mA intensity for 20 min, with anode on F4 and cathode on F3, were conducted. Simultaneous with tDCS sessions, and based on TMNMT, the participant was asked to listen passively for 120 min/day, to a CD containing her/his favorite music with a proper notch applied in its spectrum according to the individual's tinnitus The treatment outcome was measured by, psychoacoustic (loudness-matching), psychometric (awareness, loudness and annoyance Visual Analogue Scale (VAS) scores, and Tinnitus Handicap Inventory (THI)) scores, and cognitive assessments (randomized dichotic digits test (RDDT) and dichotic auditory-verbal memory test (DAVMT)). Repeated measurement test was used for statistical analyses.

RESULTS

In the CTG, the tinnitus loudness and annoyance VAS scores, and THI were reduced significantly (p = 0.001). In addition, the DAVMT and RDDT scores were enhanced (p = 0.001). Such changes were not observed in the CG (p > 0.05).

CONCLUSION

The combination of tDCS and TMNMT led to a reduction in the loudness, awareness, annoyance, and also disability induced by tinnitus in CTG. Furthermore, this method showed an improvement of cognitive functions (auditory divided attention, selective attention and working memory) in the CTG.

Medication Use Reported by Individuals With Tinnitus Who Are Seeking Internet-Based Psychological Interventions

PURPOSE

This study examined medication use by individuals with tinnitus who were seeking help for their tinnitus by means of a psychological intervention.

METHOD

This study used a cross-sectional survey design and included individuals with tinnitus enrolled in an Internet-based cognitive behavioral therapy trial (n = 439). Study participants provided demographic details, completed various structured questionnaires and provided details about the medications used. The self-reported medications were classified using the United States Pharmacopeial Medicare Model Guidelines v7.0.

RESULTS

Current medication use was reported by 67% (n = 293) of the study participants. Those currently using medication were older; had consulted their primary care physician, had greater tinnitus severity, depression, anxiety, and insomnia when compared with those not reporting any current medication use. The top 10 medication used included cardiovascular agents (n = 162; 55.3%), antidepressants (n = 80; 27.3%), electrolytes/minerals/metals/vitamins (n = 70; 23.9%), respiratory tract/pulmonary agents (n = 62; 21.2%), anxiolytics (n = 59; 20.1%), hormonal agents/stimulant/replacement/modifying (thyroid; n = 45; 15.4%), gastrointestinal agents (n = 43; 14.7%), analgesics (n = 33; 11.3%), blood glucose regulators (n = 32; 10.9%), and anticonvulsants (n = 26; 8.87%). Some associations between type of medication used and demographic or tinnitus-related variables were noted especially for the cardiovascular agents, electrolytes/minerals/metals/vitamins, and anxiolytics.

CONCLUSIONS

This exploratory study indicated a large percentage of patients using medication and a range of medications. Further studies are required to assess the effects of such medications on the tinnitus percept and concurrent medication moderate treatment effects.

Unification of Treatments and Interventions for Tinnitus Patients (UNITI): a study protocol for a multi-center randomized clinical trial

BACKGROUND

Tinnitus represents a relatively common condition in the global population accompanied by various comorbidities and severe burden in many cases. Nevertheless, there is currently no general treatment or cure, presumable due to the heterogeneity of tinnitus with its wide variety of etiologies and tinnitus phenotypes. Hence, most treatment studies merely demonstrated improvement in a subgroup of tinnitus patients. The majority of studies are characterized by small sample sizes, unstandardized treatments and assessments, or applications of interventions targeting only a single organ level. Combinatory treatment approaches, potentially targeting multiple systems as well as treatment personalization, might provide remedy and enhance treatment responses. The aim of the present study is to systematically examine established tinnitus therapies both alone and in combination in a large sample of tinnitus patients. Further, it wants to provide the basis for personalized treatment approaches by evaluating a specific decision support system developed as part of an EU-funded collaborative project (Unification of treatments and interventions for tinnitus patients; UNITI project).

METHODS/STUDY DESIGN

This is a multi-center parallel-arm randomized clinical trial conducted at five different clinical sites over the EU. The effect of four different tinnitus therapy approaches (sound therapy, structured counseling, hearing aids, cognitive behavioral therapy) applied over a time period of 12 weeks as a single or rather a combinatory treatment in a total number of 500 chronic tinnitus patients will be investigated. Assessments and interventions are harmonized over the involved clinical sites. The primary outcome measure focuses on the domain tinnitus distress assessed via the Tinnitus Handicap Inventory.

DISCUSSION

Results and conclusions from the current study might not only provide an essential contribution to combinatory and personalized treatment approaches in tinnitus but could also provide more profound insights in the heterogeneity of tinnitus, representing an important step towards a cure for tinnitus.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04663828 . Registered on 11 December 2020.