Underlying mechanisms of tinnitus: review and clinical implications

Tinnitus mechanisms and the need for an objective electrophysiological tinnitus test

Tinnitus, the perception of sound with no external auditory stimulus, is a complex, multifaceted, and potentially devastating disorder. Despite recent advances in our understanding of tinnitus, there are limited options for effective treatment. Tinnitus treatments are made more complicated by the lack of a test for tinnitus based on objectively measured physiological characteristics. Such an objective test would enable a greater understanding of tinnitus mechanisms and may lead to faster treatment development in both animal and human research. This review makes the argument that an objective tinnitus test, such as a non-invasive electrophysiological measure, is desperately needed. We review the current tinnitus assessment methods, the underlying neural correlates of tinnitus, the multiple tinnitus generation theories, and the previously investigated electrophysiological measurements of tinnitus. Finally, we propose an alternate objective test for tinnitus that may be valid in both animal and human subjects.

Investigating the effectiveness of music therapy combined with binaural beats on chronic tinnitus: A randomized controlled trial

BACKGROUND

Binaural beat stimulation (BBS) involve presenting two sinusoidal waves with specific frequency differences to induce neural changes in the brain, often used for mental state induction and symptom reduction. However, there are limited studies on its effectiveness for tinnitus. This study aimed to assess the effectiveness of combining binaural beats with music containing nature sounds for chronic tinnitus.

METHODS

A total of 30 men, aged 45.87 on average (SD = 8.09), who had chronic tinnitus and symmetrical mild to moderate hearing loss, were included in this study. The participants were randomly assigned to two groups: MT group (Music therapy; n = 15), which received relaxing music containing the sound of sea waves, and MT + BBS group (Music therapy plus binaural beats; n = 15), which received the same music combined with alpha frequency (8 Hz) binaural beats. The therapy sessions were conducted twice a day for 15 min, over a period of 4 weeks. Outcome measures, including the Tinnitus Handicap Inventory (THI), Tinnitus Functional Index (TFI), Hospital Anxiety and Depression Scale (HADS), Visual Analog Scale (VAS) and the pitch and loudness of tinnitus were administered before, immediately after, and during the three-month follow-up period.

RESULTS

The findings revealed improvements in loudness and annoyance VAS, as well as THI total and all subscale scores in both groups (p < 0.001). Additionally, TFI total score showed improvement in both groups (MT: p = 0.001; MT + BBS: p < 0.001) except for the sense of control subscale in both groups and the cognitive subscale in the MT group after the treatment and during the three-month follow-up period. Furthermore, both groups exhibited a decrease in scores for both subscales of HADS. However, there were no significant differences between the two groups in any of the measurement outcomes (p > 0.05), except for the emotional subscale scores of TFI (p = 0.049) and the functional subscale scores of THI (p = 0.034). In other words, during the follow-up period, the MT + BBS group exhibited lower scores in these two subscales compared to the MT group.

CONCLUSION

Although our study failed to demonstrate the superiority of combining binaural beats with music, both groups experienced significant improvements. This suggest that there are potential benefits to be gained from these types of stimuli. Given the sustained effect of both methods and the even greater improvements in follow-up observed in the binaural beats group for some scales, it seems that the changes in neural response and brain waves caused by our stimulations are persistent. This necessitates further research involving brain mapping, especially with longer follow-up durations.

Differences in brain functional connectivity between tinnitus with or without hearing loss

To explore the differences in brain imaging in tinnitus with or without hearing loss (HL). We acquired functional MRI scans from 26 tinnitus patients with HL (tinnitus-HL), 24 tinnitus patients with no HL (tinnitus-NHL), and 26 healthy controls (HCs) matched by age and sex. The left and right thalamus were selected as seeds to study the endogenous functional connectivity (FC) of the whole brain, and its correlation with clinical indices was analyzed. Brain regions showing FC differences among the three groups included the Heschl gyrus (HES), right Hippocampus (HIP), right Amygdala (AMYG), left Calcarine fissure and surrounding cortex (CAL). Post hoc analysis showed that the thalamus-HIP connection and thalamus-lingual gyrus (LING) connection were enhanced in the tinnitus-NHL group, as compared to tinnitus-HL. Compared with HCs, the tinnitus-NHL group showed an enhanced connection between the thalamus and the left Inferior occipital gyrus, left CAL and LING. While in the tinnitus-HL group, the connection between the thalamus and several brain regions (right HES, right AMYG, etc) was weakened. In the tinnitus-HL group, the tinnitus handicap inventory scores were positively correlated with the FC of the left thalamus and right HES, right thalamus and right Rolandic operculum. The duration of tinnitus was negatively correlated with the FC of the right thalamus and right HIP. Abnormal FC in the thalamus may play an important role in the pathogenesis of tinnitus. Tinnitus-NHL and tinnitus-HL show different connection patterns, indicating that there are some differences in their pathogenesis.

Impact of Migraine and Vestibular Migraine on Audiometric Profiles and Quality of Life in Patients With Tinnitus

OBJECTIVE

To investigate the clinical manifestations and complete auditory function in primary tinnitus patients with and without migraine or vestibular migraine.

DESIGN

Retrospective case-control study.

SETTING

A tertiary referral center.

PARTICIPANTS

This study enrolled 298 patients from the Kaohsiung Veterans General Hospital. All patients were diagnosed with primary tinnitus by a neurotologist between April 2020 and August 2021. Patients were excluded if they had histories of chronic otitis media, idiopathic sudden sensorineural hearing loss, Ménière's disease, skull base neoplasm, or temporal bone trauma.

INTERVENTIONS

Twenty-five-item Tinnitus Handicap Inventory (THI), speech audiometry including speech recognition threshold, most comfortable level, uncomfortable loudness levels, dynamic range, and pure-tone audiometry.

MAIN OUTCOMES MEASURES

Objective hearing loss is defined as a mean threshold greater than 25 dB. Extremely elevated THI is defined as a score greater than 1 standard deviation above the mean THI.

RESULTS

Among the 298 patients with tinnitus, 149 were women and 149 were men, with a mean age of 57.06 (range, 19.22-94.58) years.A total of 125 patients completed the THI questionnaire during their initial visit. The median THI score was 32 (95% confidence interval: 13.98-56.00), and the mean score was 34.99 with a standard deviation of 21.01. The sole contributing factor significantly associated with higher total THI score was the diagnosis of migraine or vestibular migraine (p < 0.001, odds ratio = 19.41).Tinnitus patients with migraine or vestibular migraine exhibited significantly lower mean pure-tone auditory thresholds (right 22.2 versus 29.5, p = 0.002; left 22.5 versus 30.4, p < 0.001), speech recognition threshold (right 20.0 versus 25.2, p = 0.016; left 20.2 versus 25.5, p = 0.019), and most comfortable levels values (right 46.1 versus 51.4, p = 0.007; left 46.9 versus 51.4, p = 0.021) compared with the tinnitus patients without migraine.

CONCLUSIONS

In this population-based study, patients with primary tinnitus experienced significantly higher THI scores and exhibited concurrent symptoms, including dizziness/vertigo, cervicalgia, and migraine or vestibular migraine. Among these parameters, the diagnosis of migraine or vestibular migraine was the sole contributor to significant higher THI score.

Tinnitus in Children

This perspective reviews the current state of the art and literature on tinnitus in children, prevalence and risk factors, clinical management, and future priorities for healthcare provision and research. Most research in the field to date appears to be prevalence studies, which have reached dramatically different estimates; this reflects the lack of a standard language when asking about the presence of tinnitus, or how bothersome, distressing, or negatively impacting it is for the child. Estimates are also likely affected by a lack of awareness of tinnitus amongst children and parents. Children are less likely to spontaneously report tinnitus than adults, and parents are often unaware their child could even develop tinnitus, considering it a disease of older age for example. It is critical that children are asked and learn about tinnitus. In hearing clinics, clinicians should routinely ask about all children about tinnitus and offer tinnitus care and settings that are child- and family-friendly. As well as asking directly, clinicians should be alert to soft signs of tinnitus such as unexplained listening, speech perception, concentration difficulties, worry or anxiety, or difficulties completing hearing tests or using hearing aids. The recently developed impact of Tinnitus in Children Questionnaire (iTICQ) can then be used to assess problems that are most commonly core to children's experience of tinnitus. Clinical guidelines for tinnitus in children are few but provide recommendations for additional paediatric questionnaires and alternative assessments and for a range of treatment options. Of note, however, is the lack of clinical trials and, therefore, evidence of the effectiveness of any treatment for tinnitus in children. Significant and concerted work is therefore needed to raise awareness of tinnitus in children, understand the scale of clinical need, and standardise and evaluate clinical management options.

ChatGPT for Tinnitus Information and Support: Response Accuracy and Retest after Three and Six Months

Testing of ChatGPT has recently been performed over a diverse range of topics. However, most of these assessments have been based on broad domains of knowledge. Here, we test ChatGPT's knowledge of tinnitus, an important but specialized aspect of audiology and otolaryngology. Testing involved evaluating ChatGPT's answers to a defined set of 10 questions on tinnitus. Furthermore, given the technology is advancing quickly, we re-evaluated the responses to the same 10 questions 3 and 6 months later. The accuracy of the responses was rated by 6 experts (the authors) using a Likert scale ranging from 1 to 5. Most of ChatGPT's responses were rated as satisfactory or better. However, we did detect a few instances where the responses were not accurate and might be considered somewhat misleading. Over the first 3 months, the ratings generally improved, but there was no more significant improvement at 6 months. In our judgment, ChatGPT provided unexpectedly good responses, given that the questions were quite specific. Although no potentially harmful errors were identified, some mistakes could be seen as somewhat misleading. ChatGPT shows great potential if further developed by experts in specific areas, but for now, it is not yet ready for serious application.

[Rational timepoint of medical rehabilitation in chronic tinnitus : Applying for rehabilitation options for a chronic course]

Chronic tinnitus is a common symptom of the auditory system. A causal therapy does not yet exist. The recommended treatment includes expert counseling, psychotherapeutic interventions, particularly cognitive behavioral therapy, and measures to improve hearing. The treatment modules are multimodal and can be combined individually. Depending on the severity of the different disease dimensions (tinnitus and comorbidities), a rehabilitative approach may be useful for maintaining health and occupational ability. In addition to a thorough and well-founded diagnosis and counseling, specific cognitive behavioral therapy and non-specific psychotherapeutic interventions (mindfulness/relaxation) on an individual or group basis, physiotherapy, and exercise, as well as auditory rehabilitation measures (hearing aids, auditory therapy) in the context of multimodal therapy approaches are necessary.

Therapy effect of cochleural alternating acoustic beam therapy versus traditional sound therapy for managing chronic idiopathic tinnitus patients

Idiopathic tinnitus is a common and complex disorder with no established cure. The CAABT (Cochleural Alternating Acoustic Beam Therapy CAABT), is a personalized sound therapy designed to target specific tinnitus frequencies and effectively intervene in tinnitus according to clinical tinnitus assessment. This study aimed to compare the effectiveness of the CAABT and Traditional Sound Therapy (TST) in managing chronic idiopathic tinnitus. This was a randomized, double-blind, parallel-group, single-center prospective study. Sixty adult patients with tinnitus were recruited and randomly assigned to the CAABT or TST group in a 1:1 ratio using a computer-generated randomization. The treatment lasted for 12 weeks, and participants underwent assessments using the tinnitus handicap inventory (THI), visual analog scale (VAS), tinnitus loudness measurements, and resting-state functional magnetic resonance imaging (rs-fMRI). Both groups showed significant reductions in THI scores, VAS scores, and tinnitus loudness after treatment. However, CAABT showed superiority to TST in THI Functional (p = 0.018), THI Emotional (p = 0.015), THI Catastrophic (p = 0.022), THI total score (p = 0.005) as well as VAS score (p = 0.022). More interesting, CAABT showed superiority to TST in the changes of THI scores, and VAS scores from baseline. The rs-fMRI results showed significant changes in the precuneus before and after treatment in both groups. Moreover, the CAABT group showed more changes in brain regions compared to the TST. No side effects were observed. These findings suggest that CAABT may be a promising treatment option for chronic idiopathic tinnitus, providing significant improvements in tinnitus-related symptoms and brain activity.Trial registration: ClinicalTrials.gov:NCT02774122.

Intermediate Cervical Plexus Block in the Management of Refractory Somatosensory Tinnitus Following Whiplash: Prospective Series in 30 Patients

OBJECTIVE

Whiplash-associated disorder comprises of a constellation of persistent symptoms after neck trauma. Tinnitus that develops postwhiplash is termed somatosensory tinnitus. The objective is to assess the role of intermediate cervical plexus block (iCPB) in patients with somatosensory tinnitus secondary to whiplash.

METHODS

Prospective service evaluation in adults with whiplash-associated disorder and concomitant somatosensory tinnitus. Patients underwent specialist otorhinolaryngology review before pain clinic referral. Patients were offered ultrasound-guided iCPB with steroids. Intensity of tinnitus was recorded on a numerical rating scale at baseline, 3 and 6 months posttreatment. Brief Pain Inventory Short Form and Hospital Anxiety Depression Scale questionnaires were also completed.

RESULTS

Over a 36-month period, 32 patients with refractory somatosensory tinnitus following whiplash were offered iCPB(s). Two patients refused because of needle phobia. iCPB(s) was performed in 30 patients as an outpatient procedure. One patient (1/30, 3.3%) was lost to follow-up. Twenty-three patients (23/30, 77%) reported clinically significant reduction in intensity of tinnitus at 3 months postprocedure. Nineteen patients (19/30, 63%) reported ongoing benefit at 6-month follow-up. Six patients failed to report any benefit (6/30, 20%).

CONCLUSION

The cervical plexus could play a significant role in the development of somatosensory tinnitus after whiplash. iCPB may have a role in the management of somatosensory tinnitus in this cohort.

Consensus Statements on the Definition, Classification, and Diagnostic Tests for Tinnitus: A Delphi Study Conducted by the Korean Tinnitus Study Group

BACKGROUND

Tinnitus is a bothersome condition associated with various symptoms. However, the mechanisms of tinnitus are still uncertain, and a standardized assessment of the diagnostic criteria for tinnitus is required. We aimed to reach a consensus on diagnosing tinnitus with professional experts by conducting a Delphi study with systematic review of the literature.

METHODS

Twenty-six experts in managing tinnitus in Korea were recruited, and a two-round modified Delphi study was performed online. The experts evaluated the level of agreement of potential criteria for tinnitus using a scale of 1-9. After the survey, a consensus meeting was held to establish agreement on the results obtained from the Delphi process. Consensus was defined when over 70% of the participants scored 7-9 (agreement) and fewer than 15% scored 1-3 (disagreement). To analyze the responses of the Delphi survey, the content validity ratio and Kendall's coefficient of concordance were evaluated.

RESULTS

Consensus was reached for 22 of the 38 statements. For the definition of tinnitus, 10 out of 17 statements reached consensus, with three statements achieving complete agreement including; 1) Tinnitus is a conscious perception of an auditory sensation in the absence of a corresponding external stimulus, 2) Tinnitus can affect one's quality of life, and 3) Tinnitus can be associated with hearing disorders including sensorineural hearing loss, vestibular schwannoma, Meniere's disease, otosclerosis, and others. For the classification of tinnitus, 11 out of 18 statements reached consensus. The participants highly agreed with statements such as; 1) Vascular origin is expected in pulse-synchronous tinnitus, and 2) Tinnitus can be divided into acute or chronic tinnitus. Among three statements on the diagnostic tests for tinnitus only Statement 3, "There are no reliable biomarkers for sensory or emotional factors of tinnitus." reached consensus. All participants agreed to perform pure-tone audiometry and tinnitus questionnaires, including the Tinnitus Handicap Inventory and Tinnitus Questionnaire.

CONCLUSION

We used a modified Delphi method to establish a consensus-based definition, a classification, and diagnostic tests for tinnitus. The expert panel reached agreement for several statements, with a high level of consensus. This may provide practical information for clinicians in managing tinnitus.

History of Tinnitus Research at the VA National Center for Rehabilitative Auditory Research (NCRAR), 1997-2021: Studies and Key Findings

The Veterans Affairs (VA) Rehabilitation Research & Development (RR&D) National Center for Rehabilitative Auditory Research (NCRAR) was first funded by the RR&D Service in 1997 and has been funded continuously since that time. The overall purpose of the NCRAR is to "improve the quality of life of Veterans and others with hearing and balance problems through clinical research, technology development, and education that leads to better patient care" ( www.ncrar.research.va.gov ). An important component of the research conducted at the NCRAR has been a focus on clinical and rehabilitative aspects of tinnitus. Multiple investigators have received grants to conduct tinnitus research and the present article provides an overview of this research from the NCRAR's inception through 2021.

Arachnoid Cyst of the Cerebellopontine Angle: A Systematic Literature Review

OBJECTIVE

The role of surgical management of arachnoid cyst (AC) of the cerebellopontine angle (CPA) is uncertain. This topic has remained controversial with varying contradictory recommendations in the literature, which is limited to mostly case reports. We aimed to provide a comprehensive summary and analysis of symptoms, operative techniques, outcomes, and recurrence of all available surgical cases of AC of the CPA to date.

METHODS

A systematic literature search was performed in May 2022 querying several scientific databases. Inclusion criteria specified all studies and case reports of patients with AC located at the CPA for which any relevant surgical procedures were performed.

RESULTS

A total of 55 patients from the literature and 5 treated at our institution were included. Mean patient age was 29 years (range, 0.08-79 years), with nearly twice (1.7×) as many female as male patients (37 female, 22 male). Headaches (35%), hearing loss (30%), vertigo (22%), and ataxia (22%) were the most common presentations. Following surgery, 95% experienced symptom improvement, with complete resolution in 64%. Of patients with hearing loss, 44% reported a return to normal. The rate of mortality was 1.69%, and 10% of tumors recurred (mean follow-up 2.3 years [range, 0-15 years].

CONCLUSIONS

Symptomatic AC of the CPA is rare. It exhibits a proclivity for females and commonly manifests with headache, hearing loss, vertigo, and ataxia. While careful selection for surgical candidacy is needed and intervention should be reserved for patients with severe symptoms, surgical decompression is an effective tool for symptom alleviation and recovery.

Cross-Modal Tinnitus Remediation: A Tentative Theoretical Framework

Tinnitus is a prevalent hearing-loss deficit manifested as a phantom (internally generated by the brain) sound that is heard as a high-frequency tone in the majority of afflicted persons. Chronic tinnitus is debilitating, leading to distress, sleep deprivation, anxiety, and even suicidal thoughts. It has been theorized that, in the majority of afflicted persons, tinnitus can be attributed to the loss of high-frequency input from the cochlea to the auditory cortex, known as deafferentation. Deafferentation due to hearing loss develops with aging, which progressively causes tonotopic regions coding for the lost high-frequency coding to synchronize, leading to a phantom high-frequency sound sensation. Approaches to tinnitus remediation that demonstrated promise include inhibitory drugs, the use of tinnitus-specific frequency notching to increase lateral inhibition to the deafferented neurons, and multisensory approaches (auditory-motor and audiovisual) that work by coupling multisensory stimulation to the deafferented neural populations. The goal of this review is to put forward a theoretical framework of a multisensory approach to remedy tinnitus. Our theoretical framework posits that due to vision's modulatory (inhibitory, excitatory) influence on the auditory pathway, a prolonged engagement in audiovisual activity, especially during daily discourse, as opposed to auditory-only activity/discourse, can progressively reorganize deafferented neural populations, resulting in the reduced synchrony of the deafferented neurons and a reduction in tinnitus severity over time.

The potassium channels: Neurobiology and pharmacology of tinnitus

Tinnitus is a widespread public health issue that imposes a significant social burden. The occurrence and maintenance of tinnitus have been shown to be associated with abnormal neuronal activity in the auditory pathway. Based on this view, neurobiological and pharmacological developments in tinnitus focus on ion channels and synaptic neurotransmitter receptors in neurons in the auditory pathway. With major breakthroughs in the pathophysiology and research methodology of tinnitus in recent years, the role of the largest family of ion channels, potassium ion channels, in modulating the excitability of neurons involved in tinnitus has been increasingly demonstrated. More and more potassium channels involved in the neural mechanism of tinnitus have been discovered, and corresponding drugs have been developed. In this article, we review animal (mouse, rat, hamster, and guinea-pig), human, and genetic studies on the different potassium channels involved in tinnitus, analyze the limitations of current clinical research on potassium channels, and propose future prospects. The aim of this review is to promote the understanding of the role of potassium ion channels in tinnitus and to advance the development of drugs targeting potassium ion channels for tinnitus.

Rare Deletions or Large Duplications Contribute to Genetic Variation in Patients with Severe Tinnitus and Meniere Disease

Meniere disease (MD) is a debilitating disorder of the inner ear defined by sensorineural hearing loss (SNHL) associated with episodes of vertigo and tinnitus. Severe tinnitus, which occurs in around 1% of patients, is a multiallelic disorder associated with a burden of rare missense single nucleotide variants in synaptic genes. Rare structural variants (SVs) may also contribute to MD and severe tinnitus. In this study, we analyzed exome sequencing data from 310 MD Spanish patients and selected 75 patients with severe tinnitus based on a Tinnitus Handicap Inventory (THI) score > 68. Three rare deletions were identified in two unrelated individuals overlapping the ERBB3 gene in the positions: NC_000012.12:g.56100028_56100172del, NC_000012.12:g.56100243_56101058del, and NC_000012.12:g.56101359_56101526del. Moreover, an ultra-rare large duplication was found covering the AP4M1, COPS6, MCM7, TAF6, MIR106B, MIR25, and MIR93 genes in another two patients in the NC_000007.14:g.100089053_100112257dup region. All the coding genes exhibited expression in brain and inner ear tissues. These results confirm the contribution of large SVs to severe tinnitus in MD and pinpoint new candidate genes to get a better molecular understanding of the disease.

Mice prone to tinnitus after acoustic trauma show increased pre-exposure sensitivity to background noise

Noise-induced tinnitus is generally associated with hearing impairment caused by traumatic acoustic overexposure. Previous studies in laboratory animals and human subjects, however, have observed differences in tinnitus susceptibility, even among individuals with similar hearing loss. The mechanisms underlying increased sensitivity or, conversely, resistance to tinnitus are still incompletely understood. Here, we used behavioral tests and ABR audiometry to compare the sound-evoked responses of mice that differed in the presence of noise-induced tinnitus. The aim was to find a specific pre-exposure neurophysiological marker that would predict the development of tinnitus after acoustic trauma. Noise-exposed mice were screened for tinnitus-like behavior with the GPIAS paradigm and subsequently divided into tinnitus (+T) and non-tinnitus (-T) groups. Both groups showed hearing loss after exposure, manifested by elevated audiometric thresholds along with reduced amplitudes and prolonged latencies of ABR waves. Prior to exposure, except for a slightly increased slope of growth function for ABR amplitudes in +T mice, the two groups did not show significant audiometric differences. Behavioral measures, such as the magnitude of the acoustic startle response and its inhibition by gap pre-pulse, were also similar before exposure in both groups. However, +T mice showed significantly increased suppression of the acoustic startle response in the presence of background noise of moderate intensity. Thus, increased modulation of startle by background sounds may represent a behavioral correlate of susceptibility to noise-induced tinnitus, and its measurement may form the basis of a simple non-invasive method for predicting tinnitus development in laboratory rodents.

Evidence of cochlear neural degeneration in normal-hearing subjects with tinnitus

Tinnitus, reduced sound-level tolerance, and difficulties hearing in noisy environments are the most common complaints associated with sensorineural hearing loss in adult populations. This study aims to clarify if cochlear neural degeneration estimated in a large pool of participants with normal audiograms is associated with self-report of tinnitus using a test battery probing the different stages of the auditory processing from hair cell responses to the auditory reflexes of the brainstem. Self-report of chronic tinnitus was significantly associated with (1) reduced cochlear nerve responses, (2) weaker middle-ear muscle reflexes, (3) stronger medial olivocochlear efferent reflexes and (4) hyperactivity in the central auditory pathways. These results support the model of tinnitus generation whereby decreased neural activity from a damaged cochlea can elicit hyperactivity from decreased inhibition in the central nervous system.

[Somatosensory tinnitus]

BACKGROUND

Somatosensory tinnitus represents a clinically significant subgroup of chronic tinnitus. Although not completely understood, increasing evidence suggests interactivity between the somatosensory and auditory systems is responsible for both the development and maintenance of tinnitus.

OBJECTIVES

The aim of this study is to provide an overview of the evaluation of somatosensory tinnitus and to propose an examination protocol to support the diagnosis and treatment of this patient group.

MATERIALS AND METHODS

In addition to patient history, various clinical examination maneuvers are presented to establish the diagnosis of somatosensory tinnitus.

RESULTS

The maneuvers can be divided into examinations of the cervical spine, temporomandibular joint, and soft tissue near the jaw. The maneuvers should be performed in a quiet environment and usually in comparison between sides.

CONCLUSION

Accurate and efficient diagnosis of somatosensory tinnitus is essential to initiate appropriate treatment. The clinical maneuvers presented here are well suited for this purpose.

Candidate Key Proteins in Tinnitus: A Bioinformatic Study of Synaptic Transmission in Spiral Ganglion Neurons

To study key proteins associated with changes in synaptic transmission in the spiral ganglion in tinnitus, we build three gene lists from the GeneCard database: 1. Perception of sound (PoS), 2. Acoustic stimulation (AcouStim), and 3. Tinnitus (Tin). Enrichment analysis by the DAVID database resulted in similar Gene Ontology (GO) terms for cellular components in all gene lists, reflecting synaptic structures known to be involved in auditory processing. The STRING protein-protein interaction (PPI) network and the Cytoscape data analyzer were used to identify the top two high-degree proteins (HDPs) and their high-score interaction proteins (HSIPs) identified by the combined score (CS) of the corresponding edges. The top two protein pairs (key proteins) for the PoS are BDNF-GDNF and OTOF-CACNA1D and for the AcouStim process BDNF-NTRK2 and TH-CALB1. The Tin process showed BDNF and NGF as HDPs, with high-score interactions with NTRK1 and NGFR at a comparable level. Compared to the PoS and AcouStim process, the number of HSIPs of key proteins (CS > 90. percentile) increases strongly in Tin. In the PoS and AcouStim networks, BDNF receptor signaling is the dominant pathway, and in the Tin network, the NGF-signaling pathway is of similar importance. Key proteins and their HSIPs are good indicators of biological processes and of signaling pathways characteristic for the normal hearing on the one hand and tinnitus on the other.

The Effect of Tinnitus and Related Characteristics on Subcortical Auditory Processing

OBJECTIVES

The primary aim of this study was to evaluate whether individuals with tinnitus exhibited evidence of reduced inhibition and increased excitation at the subcortical auditory processing level. Based on the proposed mechanism of tinnitus generation, including peripheral auditory insult that triggers reduced inhibition and subcortical hyperactivity, it was hypothesized that a tinnitus group would yield reduced amplitudes for the most peripheral auditory brainstem response (ABR) component (wave I) and larger amplitudes for the most central ABR component (wave V) relative to controls matched on factors of age, sex, and hearing loss. Further, this study assessed the relative influence of tinnitus presence versus other related individual characteristics, including hearing loss, age, noise exposure history, and speech perception in noise on these ABR outcomes.

DESIGN

Subcortical processing was examined using click-evoked ABR in an independent groups experimental design. A group of adults who perceived daily unilateral or bilateral tinnitus were matched with a control group counterpart without tinnitus by age, hearing, and sex (in each group n = 18; 10 females, 8 males). Amplitudes for ABR waves I, III, V, and the V/I ratio were compared between groups by independent t-tests. The relative influence of tinnitus (presence/absence), age (in years), noise exposure history (subjective self-report), hearing loss (audiometric thresholds), and speech perception in noise (SNR-50) was determined based on the proportional reduction in error associated with accounting for each variable of interest using multiple regression.

RESULTS

Between-group trends were consistent with smaller amplitudes for all ABR components in individuals with tinnitus. Contrary to our hypotheses, however, none of the tinnitus compared with control group differences in ABR outcomes were statistically significant. In the multiple regression models, none of the factors including tinnitus presence, age, noise exposure history, hearing loss, and speech perception in noise significantly predicted ABR V/I ratio outcomes.

CONCLUSIONS

The presence of reduced inhibition and subcortical hyperactivity in the tinnitus group was not supported in the current study. There were trends in ABR outcomes consistent with reduced peripheral to central brainstem auditory activity in the tinnitus group, but none of the group differences reached significance. It should also be noted that the tinnitus group had poorer extended high-frequency thresholds compared with controls. Regardless, neither tinnitus presence nor any of the proposed related characteristics were found to significantly influence the ABR V/I ratio. These findings suggest that either reduced subcortical inhibition was not a primary underlying mechanism for the tinnitus perceived by these subjects, or that ABR was not a reliable indicator of reduced subcortical inhibition possibly due to characteristics of the sample including a skewed distributions toward young and normal hearing individuals with little tinnitus distress.

The human neuroprotective placental protein composition suppressing tinnitus and restoring auditory brainstem response in a rodent model of sodium salicylate-induced ototoxicity

The effect of neuroprotective placental protein composition (NPPC) on the suppression of tinnitus and the restoration of the auditory brainstem response (ABR) characteristics was explored in tinnitus-induced rats. The animals were placed into two groups: (1) the study group, rats received sodium salicylate (SS) at the dose of 200 mg/kg twice a day for two weeks, and then 0.4 mg of the NPPC per day, between the 14th and 28th days, (2) the placebo group, rats received saline for two weeks, and then the NPPC alone between the 14th and 28th days. The gap pre-pulse inhibition of the acoustic startle (GPIAS), the pre-pulse inhibition (PPI), and the ABR assessments were performed on animals in both groups three times (baseline, day 14, and 28). The GPIAS value declined after 14 consecutive days of the SS injection, while NPPC treatment augmented the GPIAS score in the study group on the 28th day. The PPI outcomes revealed no significant changes, indicating hearing preservation after the SS and NPPC administrations. Moreover, some changes in ABR characteristics were observed following SS injection, including (1) higher ABR thresholds, (2) lowered waves I and II amplitudes at the frequencies of 6, 12, and 24 kHz and wave III at the 12 kHz, (3) elevated amplitude ratios, and (4) prolongation in brainstem transmission time (BTT). All the mentioned variables returned to their normal values after applying the NPPC. The NPPC use could exert positive therapeutic effects on the tinnitus-induced rats and improve their ABR parameters.

Does it matter what is trained? A randomized controlled trial evaluating the specificity of alpha/delta ratio neurofeedback in reducing tinnitus symptoms

Previous studies showed that alpha/delta ratio neurofeedback was effective in reducing unpleasant psychological, emotional and perceptual consequences of tinnitus. The main goal of the present study was to investigate, whether the specific combination of enhancing alpha frequency band activity and reducing delta frequency band activity was necessary, or merely sufficient, to obtain a positive treatment outcome regarding tinnitus distress and intensity. A second research aim was to assess the relative contribution of neurofeedback-related non-specific and general non-specific effects in neurofeedback treatment. In a three-arm, randomized controlled trial, 94 chronic tinnitus patients were randomly assigned to one of three conditions: alpha/delta ratio neurofeedback (n = 31), beta/theta ratio neurofeedback (n = 28) and non-neurofeedback minimal treatment intervention (n = 35). Neurofeedback participants underwent 10 treatment sessions over a 4-week period. Outcome measures were collected pre-, mid- and post-interventions and at 3-months follow-up. The Tinnitus Handicap Inventory and the Tinnitus Magnitude Index were used as primary outcome measures for tinnitus distress and tinnitus intensity. EEG data recorded during training supplemented primary outcomes. Since data were repeated measures, the analyses used a two-level mixed effects model approach including by-subject random effects (random intercept). For the Tinnitus Handicap Inventory, the results showed no interaction effect. For the Tinnitus Magnitude Index, the analysis showed a significant time × group interaction, indicating that both alpha/delta ratio neurofeedback and beta/theta ratio neurofeedback reported reduced tinnitus intensity. Analysis of EEG data showed a consistent pattern for the alpha/delta ratio over the course of training. Compared to beta/theta ratio neurofeedback, alpha/delta ratio neurofeedback showed an elevated response. Conversely, for the beta ratio to theta ratio, the pattern was more inconsistent, with no clear indication of superiority for beta/theta ratio neurofeedback over alpha/delta ratio neurofeedback. The main question of this piece of research was whether alpha/delta ratio neurofeedback demonstrated frequency band specificity in the alleviation of tinnitus distress and perceived intensity. Results showed that alpha/delta ratio neurofeedback was sufficient but importantly 'not' necessary to achieve a positive outcome on both the Tinnitus Handicap Inventory and Tinnitus Magnitude Index, when compared to beta/theta ratio neurofeedback. Still, the data suggest a trend towards specificity for alpha/delta ratio neurofeedback. Because of this, it may be too premature to discard alpha/delta ratio neurofeedback in the treatment of tinnitus. Recommendations for future studies are outlined.

Tinnitus and Influencing Comorbidities

Numerous studies show that impairments in chronic tinnitus are closely connected with psychosomatic and other concomitant symptoms. This overview summarizes some of these studies. Beyond hearing loss, individual interactions of medical and psychosocial stress factors as well as resources are of central importance. Tinnitus related distress reflects a large number of intercorrelated, psychosomatic influences - such as personality traits, stress reactivity and depression or anxiety - which can be accompanied by cognitive difficulties and should be conceptualized and assessed within a vulnerability-stress-reaction model. Superordinate factors such as age, gender or education level can increase vulnerability to stress. Therefore, diagnosis and therapy of chronic tinnitus be individualised, multidimensional and interdisciplinary. Multimodal psychosomatic therapy approaches aim to address individually constellated medical, audiological and psychological influences in order to sustainably increase the quality of life of those affected. Counselling in the first contact is also indispensable for diagnosis and therapy.

Shortened neural conduction time in young adults with tinnitus as revealed by chirp-evoked auditory brainstem response

Tinnitus is generally considered to be caused by neuroplastic changes in the central nervous system, triggered by a loss of input from the damaged peripheral system; however, conflicting results on auditory brainstem responses (ABRs) to clicks have been reported previously in humans with tinnitus. This study aimed to compare the effect of tinnitus on ABRs to chirps with those to clicks in normal-hearing young adults with tinnitus. The results showed that the tinnitus group had no significantly poorer hearing thresholds (0.25-16 kHz), click-evoked otoacoustic emissions (1-16 kHz), and speech perception in noise (SPIN) than the control group. Although chirps evoked significantly larger wave I and V amplitudes than clicks, people with tinnitus had no significantly smaller wave I amplitudes for either stimulus. Nevertheless, adults with tinnitus exhibited significantly smaller interpeak interval (IPI) between waves I and V for chirps (IPI-chirp) but not for clicks. In addition, the IPI-chirp correlated significantly with the SPIN for individuals with tinnitus when the signal-to-noise ratio was low. The present results suggest that the chirp-evoked ABR may be a valuable clinical tool for objectively assessing the SPIN in individuals with tinnitus. Further studies should be conducted to investigate possible etiologies of tinnitus.

Noise Exposure in Palestinian Workers Without a Diagnosis of Hearing Impairment: Relations to Speech-Perception-in-Noise Difficulties, Tinnitus, and Hyperacusis

PURPOSE

Many workers in developing countries are exposed to unsafe occupational noise due to inadequate health and safety practices. We tested the hypotheses that occupational noise exposure and aging affect speech-perception-in-noise (SPiN) thresholds, self-reported hearing ability, tinnitus presence, and hyperacusis severity among Palestinian workers.

METHOD

Palestinian workers (N = 251, aged 18-70 years) without diagnosed hearing or memory impairments completed online instruments including a noise exposure questionnaire; forward and backward digit span tests; hyperacusis questionnaire; the short-form Speech, Spatial and Qualities of Hearing Scale (SSQ12); the Tinnitus Handicap Inventory; and a digits-in-noise (DIN) test. Hypotheses were tested via multiple linear and logistic regression models, including age and occupational noise exposure as predictors, and with sex, recreational noise exposure, cognitive ability, and academic attainment as covariates. Familywise error rate was controlled across all 16 comparisons using the Bonferroni-Holm method. Exploratory analyses evaluated effects on tinnitus handicap. A comprehensive study protocol was preregistered.

RESULTS

Nonsignificant trends of poorer SPiN performance, poorer self-reported hearing ability, greater prevalence of tinnitus, greater tinnitus handicap, and greater severity of hyperacusis as a function of higher occupational noise exposure were observed. Greater hyperacusis severity was significantly predicted by higher occupational noise exposure. Aging was significantly associated with higher DIN thresholds and lower SSQ12 scores, but not with tinnitus presence, tinnitus handicap, or hyperacusis severity.

CONCLUSIONS

Workers in Palestine may suffer from auditory effects of occupational noise and aging despite no formal diagnosis. These findings highlight the importance of occupational noise monitoring and hearing-related health and safety practices in developing countries.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22056701.

Chronic stress induced loudness hyperacusis, sound avoidance and auditory cortex hyperactivity

Hyperacusis, a debilitating loudness intolerance disorder, has been linked to chronic stress and adrenal insufficiency. To investigate the role of chronic stress, rats were chronically treated with corticosterone (CORT) stress hormone. Chronic CORT produced behavioral evidence of loudness hyperacusis, sound avoidance hyperacusis, and abnormal temporal integration of loudness. CORT treatment did not disrupt cochlear or brainstem function as reflected by normal distortion product otoacoustic emissions, compound action potentials, acoustic startle reflexex, and auditory brainstem responses. In contrast, the evoked response from the auditory cortex was enhanced up to three fold after CORT treatment. This hyperactivity was associated with a significant increase in glucocorticoid receptors in auditory cortex layers II/III and VI. Basal serum CORT levels remained normal after chronic CORT stress whereas reactive serum CORT levels evoked by acute restraint stress were blunted (reduced) after chronic CORT stress; similar changes were observed after chronic, intense noise stress. Taken together, our results show for the first time that chronic stress can induce hyperacusis and sound avoidance. A model is proposed in which chronic stress creates a subclinical state of adrenal insufficiency that establishes the necessary conditions for inducing hyperacusis.

Relationship Between Tinnitus and Hearing Outcomes Among US Military Personnel After Blast Injury

OBJECTIVES

To examine the association between tinnitus and hearing outcomes among US military personnel after blast injury, including any hearing loss, low-frequency hearing loss, high-frequency hearing loss, early warning shift, and significant threshold shift.

DESIGN

In this retrospective study, the Blast-Related Auditory Injury Database was queried for male military service members who had audiometric data 2 years before and after blast injury between 2004 and 2012 with no history of hearing loss or tinnitus before injury (n = 1693). Tinnitus was defined by diagnostic codes in electronic health records. Multivariable logistic regression examined the association between tinnitus and hearing outcomes, while adjusting for covariates.

RESULTS

Overall, 14.2% (n = 241) of the study sample was diagnosed with tinnitus within 2 years after blast injury. The proportions of all examined hearing outcomes were higher among service members with tinnitus than those without ( p < 0.001). In multivariable analysis, service members with tinnitus had higher adjusted odds of any hearing loss (odds ratio [OR] = 1.72, 95% confidence interval [CI] = 1.20-2.47), low-frequency hearing loss (OR = 2.77, 95% CI = 1.80-4.26), high-frequency hearing loss (OR = 2.15, 95% CI = 1.47-3.16), early warning shift (OR = 1.83, 95% CI = 1.36-2.45), and significant threshold shift (OR = 2.15, 95% CI = 1.60-2.89) compared with service members without tinnitus.

CONCLUSIONS

The findings of this study demonstrate that tinnitus diagnosed within 2 years after blast injury is associated with the examined hearing outcomes in US military personnel. Service members with blast injury who subsequently experience tinnitus should receive routine audiometric hearing conservation testing and be carefully examined for poor hearing outcomes by an audiologist.

Hearing protection and damage mitigation in Chinchillas exposed to repeated low-intensity blasts

Repeated exposures to blast overpressure (BOP) introduce hearing complaints in military service members even with the use of hearing protection devices (HPDs). Although epidemiology and animal studies have been performed to investigate the damage formation mechanism of blast-induced hearing damage, there is still a lack of understanding and therapeutic solutions, especially for HPD-protected ears. Recent studies revealed the potential therapeutic function of liraglutide, a glucagon-like peptide-1 receptor agonist, to facilitate post-blast hearing restoration in chinchillas. This study is a continuation and summary of the previous studies performed by Jiang et al. (2021, 2022) to investigate the damage mitigation function of liraglutide treatment in chinchillas with open and protected ears after repeated low-intensity blast exposures within 28 days of observation. Chinchillas were divided into six experimental groups: pre-blast treatment, post-blast treatment, and blast control with ears open or protected by earplug (EP). All animals were exposed to six consecutive blasts at the level of 3-5 psi (21-35 kPa) on Day 1. Hearing function tests including auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and middle latency response (MLR) were performed on Day 1 (pre- and post-blast) and Days 4, 7, 14, and 28 after blast exposure. Results indicated that the damage mitigation function of the liraglutide treatment in the open-ear chinchillas was reflected by the significantly lower ABR threshold shifts in the drug treatment groups than in the blast controls. In EP groups, the higher ABR wave I/V ratio and lower MLR amplitude observed in the drug-treated chinchillas suggested that the post-blast hyperactivities in the auditory system might be potentially ameliorated by the liraglutide treatment. The 28-day-long experiment showed the effect of liraglutide treatment increased with time in both open and EP groups. This study demonstrated that the use of HPDs prevented the blast-induced complications in the middle ear and reduced the damage caused in the central auditory system. The liraglutide treatment showed an effect increasing with time and different outcomes in open and EP chinchillas. This innovation in the animal model of chinchilla provides insights to investigate subtle changes in the higher-level structures of the auditory system.

Onset-offset cortical auditory evoked potential amplitude differences indicate auditory cortical hyperactivity and reduced inhibition in people with tinnitus

OBJECTIVE

The current study investigates evidence of hypothesized reduced central inhibition and/or increased excitation in individuals with tinnitus by evaluating cortical auditory onset versus offset responses.

METHODS

Cortical auditory evoked potentials (CAEPs) were recorded to the onset and offset of 3-second white noise stimuli in tinnitus and control groups matched in pairs by age, hearing, and sex (n = 26 total). Independent t-tests and 2-way mixed model ANOVA were used to evaluate onset-offset differences in amplitude, area, and latency of CAEP components by group. The predictive influence of tinnitus presence and associated participant characteristics on CAEP outcomes was assessed by multiple regression proportional reduction in error.

RESULTS

The tinnitus group had significantly larger onset minus offset P2 amplitudes (ΔP2 amplitudes) than control group participants. No other component variables differed significantly. ΔP2 amplitude was best predicted by tinnitus status and not significantly influenced by other variables such as hearing loss or age.

CONCLUSIONS

Hypothesized reduced central inhibition and/or increased excitation in tinnitus participants was partially supported by a group difference in ΔP2 amplitude.

SIGNIFICANCE

This was the first study to evaluate CAEP onset minus offset differences to investigate changes in central excitation/inhibition in individuals with tinnitus versus controls in matched groups.

Comparing tinnitus, pain, psychosocial and cognitive factors between patients with tinnitus and pain: A systematic review

OBJECTIVE

Tinnitus is a multifactorial symptom, which shows similarities with the involved mechanisms in chronic pain. The aim of this systematic review is to provide an overview of studies comparing patients with only tinnitus to patients with pain (headache, temporomandibular joint (TMJ) pain or neck pain) with or without tinnitus, regarding tinnitus-related, pain-related, psychosocial and cognitive factors.

METHODS

This systematic review was written following the PRISMA guidelines. To identify relevant articles, PubMed, Web of Science and Embase databases were searched. The risk of bias was rated using the Newcastle Ottawa scale for case-control studies.

RESULTS

Ten articles were included in the qualitative analysis. The risk of bias ranged from low to moderate. Low to moderate evidence shows that patients with tinnitus experience higher mean symptom intensity, but lower psychosocial and cognitive distress, compared to patients with pain. Inconsistent results were found for tinnitus-related factors. Low to moderate evidence points to a higher severity of hyperacusis and psychosocial distress in patients with both pain and tinnitus, compared to patients with tinnitus only, as well as for positive associations between tinnitus-related factors and the presence or intensity of pain.

CONCLUSION

This systematic review shows that psychosocial dysfunctions are more clearly present in patients with pain only, compared to patients with tinnitus only and the co-occurrence of tinnitus and pain increases psychosocial distress as well as hyperacusis severity. Some positive associations were identified between tinnitus-related and pain-related factors.

Using an appetitive operant conditioning paradigm to screen rats for tinnitus induced by intense sound exposure: Experimental considerations and interpretation

In an effort to help elucidate the neural mechanisms underlying tinnitus in humans, researchers have often relied on animal models; a preclinical approach which ultimately required that behavioral paradigms be designed to reliably screen animals for tinnitus. Previously, we developed a two-alternative forced-choice (2AFC) paradigm for rats that allowed for the simultaneous recording of neural activity at the very moments when they were reporting the presence/absence of tinnitus. Because we first validated our paradigm in rats experiencing transient tinnitus following a high-dose of sodium salicylate, the present study now sought to evaluate its utility to screen for tinnitus caused by intense sound exposure; a common tinnitus-inducer in humans. More specifically, through a series of experimental protocols, we aimed to (1) conduct sham experiments to ensure that the paradigm was able to correctly classify control rats as not having tinnitus, (2) confirm the time course over which the behavioral testing could reliably be performed post-exposure to assess chronic tinnitus, and (3) determine if the paradigm was sensitive to the variable outcomes often observed after intense sound exposure (e.g., hearing loss with our without tinnitus). Ultimately, in accordance with our predictions, the 2AFC paradigm was indeed resistant to false-positive screening of rats for intense sound-induced tinnitus, and it was able to reveal variable tinnitus and hearing loss profiles in individual rats following intense sound exposure. Taken together, the present study documents the utility of our appetitive operant conditioning paradigm to assess acute and chronic sound-induced tinnitus in rats. Finally, based on our findings, we discuss important experimental considerations that will help ensure that our paradigm is able to provide a suitable platform for future investigations into the neural basis of tinnitus.

Atypical functional hierarchy contributed to the tinnitus symptoms in patients with vestibular schwannoma

Objective

Tinnitus is frequently found in patients with vestibular schwannoma (VS), but its underlying mechanisms are currently unclear.

Methods

Both preoperative (VS _pre ) and postoperative (VS _post ) functional MR images were collected from 32 patients with unilateral VS and matched healthy controls (HCs). Connectome gradients were generated for the identification of altered regions and perturbed gradient distances. Tinnitus measurements were conducted for predictive analysis with neuroimaging-genetic integration analysis.

Results

There were 56.25% of preoperative patients and 65.63% of postoperative patients suffering from ipsilateral tinnitus, respectively. No relevant factors were identified including basic demographics info, hearing performances, tumor features, and surgical approaches. Functional gradient analysis confirmed atypical functional features of visual areas in VS _pre were rescued after tumor resection, while the gradient performance in the postcentral gyrus continues to maintain (VS _post vs. HC : P = 0.016). The gradient features of the postcentral gyrus were not only significantly decreased in patients with tinnitus (P _FDR = 0.022), but also significantly correlated with tinnitus handicap inventory (THI) score (r = -0.30, P = 0.013), THI level (r = -0.31, P = 0.010), and visual analog scale (VAS) rating (r = -0.31, P = 0.0093), which could be used to predict VAS rating in the linear model. Neuropathophysiological features linked to the tinnitus gradient framework were linked to Ribosome dysfunction and oxidative phosphorylation.

Conclusion

Altered functional plasticity in the central nervous system is involved in the maintenance of VS tinnitus.

The Relationship Between Sleep Traits and Tinnitus in UK Biobank: A Population-Based Cohort Study

OBJECTIVES

Understanding the association between sleep traits and tinnitus could help prevent and provide appropriate interventions against tinnitus. Therefore, this study aimed to assess the relationship between different sleep patterns and tinnitus.

DESIGN

A cross-sectional analysis using baseline data (2006-2010, n = 168,064) by logistic regressions was conducted to evaluate the association between sleep traits (including the overall health sleep score and five sleep behaviors) and the occurrence (yes/no), frequency (constant/transient), and severity (upsetting/not upsetting) of tinnitus. Further, a prospective analysis of participants without tinnitus at baseline (n = 9581) was performed, who had been followed-up for 7 years (2012-2019), to assess the association between new-onset tinnitus and sleep characteristics. Moreover, a subgroup analysis was also carried out to estimate the differences in sex by dividing the participants into male and female groups. A sensitivity analysis was also conducted by excluding ear-related diseases to avoid their confounding effects on tinnitus (n = 102,159).

RESULTS

In the cross-sectional analysis, participants with "current tinnitus" (OR: 1.13, 95% CI: 1.04-1.22, p = 0.004) had a higher risk of having a poor overall healthy sleep score and unhealthy sleep behaviors such as short sleep durations (OR: 1.09, 95% CI: 1.04-1.14, p < 0.001), late chronotypes (OR: 1.09, 95% CI: 1.05-1.13, p < 0.001), and sleeplessness (OR: 1.16, 95% CI: 1.11-1.22, p < 0.001) than those participants who "did not have current tinnitus." However, this trend was not obvious between "constant tinnitus" and "transient tinnitus." When considering the severity of tinnitus, the risk of "upsetting tinnitus" was obviously higher if participants had lower overall healthy sleep scores (OR: 1.31, 95% CI: 1.13-1.53, p < 0.001). Additionally, short sleep duration (OR: 1.22, 95% CI: 1.12-1.33, p < 0.001), late chronotypes (OR: 1.13, 95% CI: 1.04-1.22, p = 0.003), and sleeplessness (OR: 1.43, 95% CI: 1.29-1.59, p < 0.001) showed positive correlations with "upsetting tinnitus." In the prospective analysis, sleeplessness presented a consistently significant association with "upsetting tinnitus" (RR: 2.28, p = 0.001). Consistent results were observed in the sex subgroup analysis, where a much more pronounced trend was identified in females compared with the males. The results of the sensitivity analysis were consistent with those of the cross-sectional and prospective analyses.

CONCLUSIONS

Different types of sleep disturbance may be associated with the occurrence and severity of tinnitus; therefore, precise interventions for different types of sleep disturbance, particularly sleeplessness, may help in the prevention and treatment of tinnitus.

A genome-wide association study of tinnitus reveals shared genetic links to neuropsychiatric disorders

Tinnitus, a phantom perception of sound in the absence of any external sound source, is a prevalent health condition often accompanied by psychiatric comorbidities. Recent genome-wide association studies (GWAS) highlighted a polygenic nature of tinnitus susceptibility. A shared genetic component between tinnitus and psychiatric conditions remains elusive. Here we present a GWAS using the UK Biobank to investigate the genetic processes linked to tinnitus and tinnitus-related distress, followed by gene-set enrichment analyses. The UK Biobank sample comprised 132,438 individuals with tinnitus and genotype data. Among the study sample, 38,525 individuals reported tinnitus, and 26,889 participants mentioned they experienced tinnitus-related distress in daily living. The genome-wide association analyses were conducted on tinnitus and tinnitus-related distress. We conducted enrichment analyses using FUMA to further understand the genetic processes linked to tinnitus and tinnitus-related distress. A genome-wide significant locus (lead SNP: rs71595470) for tinnitus was obtained in the vicinity of GPM6A. Nineteen independent loci reached suggestive association with tinnitus. Fifteen independent loci reached suggestive association with tinnitus-related distress. The enrichment analysis revealed a shared genetic component between tinnitus and psychiatric traits, such as bipolar disorder, feeling worried, cognitive ability, fast beta electroencephalogram, and sensation seeking. Metabolic, cardiovascular, hematological, and pharmacological gene sets revealed a significant association with tinnitus. Anxiety and stress-related gene sets revealed a significant association with tinnitus-related distress. The GWAS signals for tinnitus were enriched in the hippocampus and cortex, and for tinnitus-related distress were enriched in the brain and spinal cord. This study provides novel insights into genetic processes associated with tinnitus and tinnitus-related distress and demonstrates a shared genetic component underlying tinnitus and psychiatric conditions. Further collaborative attempts are necessary to identify genetic components underlying the phenotypic heterogeneity in tinnitus and provide biological insight into the etiology.

Vulnerability to chronic stress and the phenotypic heterogeneity of presbycusis with subjective tinnitus

Age-related functional reserve decline and vulnerability of multiple physiological systems and organs, as well as at the cellular and molecular levels, result in different frailty phenotypes, such as physical, cognitive, and psychosocial frailty, and multiple comorbidities, including age-related hearing loss (ARHL) and/or tinnitus due to the decline in auditory reserve. However, the contributions of chronic non-audiogenic cumulative exposure, and chronic audiogenic stress to phenotypic heterogeneity of presbycusis and/or tinnitus remain elusive. Because of the cumulative environmental stressors throughout life, allostasis systems, the hypothalamus-pituitary-adrenal (HPA) and the sympathetic adrenal-medullary (SAM) axes become dysregulated and less able to maintain homeostasis, which leads to allostatic load and maladaptation. Brain-body communication via the neuroendocrine system promotes systemic chronic inflammation, overmobilization of energetic substances (glucose and lipids), and neuroplastic changes via the non-genomic and genomic actions of glucocorticoids, catecholamines, and their receptors. These systemic maladaptive alterations might lead to different frailty phenotypes and physical, cognitive, and psychological comorbidities, which, in turn, cause and exacerbate ARHL and/or tinnitus with phenotypic heterogeneity. Chronic audiogenic stressors, including aging accompanying ontological diseases, cumulative noise exposure, and ototoxic drugs as well as tinnitus, activate the HPA axis and SAM directly and indirectly by the amygdala, promoting allostatic load and maladaptive neuroplasticity in the auditory system and other vulnerable brain regions, such as the hippocampus, amygdala, and medial prefrontal cortex (mPFC). In the auditory system, peripheral deafferentation, central disinhibition, and tonotopic map reorganization may trigger tinnitus. Cross-modal maladaptive neuroplasticity between the auditory and other sensory systems is involved in tinnitus modulation. Persistent dendritic growth and formation, reduction in GABAergic inhibitory synaptic inputs induced by chronic audiogenic stresses in the amygdala, and increased dendritic atrophy in the hippocampus and mPFC, might involve the enhancement of attentional processing and long-term memory storage of chronic subjective tinnitus, accompanied by cognitive impairments and emotional comorbidities. Therefore, presbycusis and tinnitus are multisystem disorders with phenotypic heterogeneity. Stressors play a critical role in the phenotypic heterogeneity of presbycusis. Differential diagnosis based on biomarkers of metabonomics study, and interventions tailored to different ARHL phenotypes and/or tinnitus will contribute to healthy aging and improvement in the quality of life.

The Influence of Diet on Tinnitus Severity: Results of a Large-Scale, Online Survey

Optimization of dietary intake is an essential component in the multidimensional effort to prevent and manage chronic disease. Recently, demand has increased for nutrition-focused management strategies for chronic tinnitus. The primary aim of this study was to evaluate 10 dietary items for their association with changes in subjective tinnitus severity. A secondary aim was to develop an algorithm to better identify those individuals who might benefit from dietary modification strategies. A total of 5017 anonymous users of the TinnitusTalk forum completed an online survey regarding how various dietary items affected the severity of their tinnitus. Results suggest that, while intake of caffeine [positive effect (PE): 0.4%; negative effect (NE): 16.2%], alcohol (PE: 2.7%; NE: 13.3%, and salt (PE: 0.1%; NE: 9.9%) was most likely to influence tinnitus severity, it did so only for a small proportion of participants and reported effects were most commonly mild. Further, though a classification algorithm was able to leverage participant demographic, comorbidity, and tinnitus characteristics to identify those individuals most likely to benefit from dietary modification above chance levels, further efforts are required to achieve significant clinical utility. Taken together, these results do not support dietary modification as a primary treatment strategy for chronic tinnitus in the general population, though clinically meaningful effects might be observable in certain individuals.

Using coding and non-coding rare variants to target candidate genes in patients with severe tinnitus

Tinnitus is the phantom percept of an internal non-verbal set of noises and tones. It is reported by 15% of the population and it is usually associated with hearing and/or brain disorders. The role of structural variants (SVs) in coding and non-coding regions has not been investigated in patients with severe tinnitus. In this study, we performed whole-genome sequencing in 97 unrelated Swedish individuals with chronic tinnitus (TIGER cohort). Rare single nucleotide variants (SNV), large structural variants (LSV), and copy number variations (CNV) were retrieved to perform a gene enrichment analysis in TIGER and in a subgroup of patients with severe tinnitus (SEVTIN, n = 34), according to the tinnitus handicap inventory (THI) scores. An independent exome sequencing dataset of 147 Swedish tinnitus patients was used as a replication cohort (JAGUAR cohort) and population-specific datasets from Sweden (SweGen) and Non-Finish Europeans (NFE) from gnomAD were used as control groups. SEVTIN patients showed a higher prevalence of hyperacusis, hearing loss, and anxiety when they were compared to individuals in the TIGER cohort. We found an enrichment of rare missense variants in 6 and 8 high-constraint genes in SEVTIN and TIGER cohorts, respectively. Of note, an enrichment of missense variants was found in the CACNA1E gene in both SEVTIN and TIGER. We replicated the burden of missense variants in 9 high-constrained genes in the JAGUAR cohort, including the gene NAV2, when data were compared with NFE. Moreover, LSVs in constrained regions overlapping CACNA1E, NAV2, and TMEM132D genes were observed in TIGER and SEVTIN.

Longitudinal Study of Analgesic Use and Risk of Incident Persistent Tinnitus

BACKGROUND

Persistent tinnitus is common, disabling, and difficult to treat. High-dose aspirin may precipitate tinnitus, but longitudinal data on typical dose aspirin and other analgesics are scarce.

OBJECTIVE

To investigate independent associations of aspirin, NSAIDs, and acetaminophen and risk of incident persistent tinnitus.

DESIGN

Longitudinal cohort study.

SETTING

Nurses' Health Study II (1995-2017).

PARTICIPANTS

A total of 69,455 women, age 31-48 years, without tinnitus at baseline.

MAIN MEASURES

Information on analgesic use and tinnitus obtained by biennial questionnaires.

KEY RESULTS

After 1,120,936 person-years of follow-up, 10,452 cases of incident persistent tinnitus were reported. For low-dose aspirin, the risk of developing persistent tinnitus was not elevated among frequent low-dose aspirin users. For moderate dose aspirin, frequent use was associated with higher risk of tinnitus among women aged < 60 years, but not among older women (p-interactionage = 0.003). Compared with women aged < 60 using moderate-dose aspirin < 1 day/week, the multivariable-adjusted hazard ratio (MVHR, 95% CI) among women using moderate-dose aspirin 6-7 days per week was 1.16 (1.03, 1.32). Among all women, frequent non-aspirin non-steroidal anti-inflammatory drug (NSAID) or acetaminophen use was associated with higher risk. Compared with women using NSAIDs <1 day/week, the MVHR for use 4-5days/week was 1.17 (1.08, 1.28) and for 6-7days/week was 1.07 (1.00, 1.16) (p-trend=0.001). For acetaminophen, compared with use <1 day/week, the MVHR for use 6-7days/week was 1.18 (1.07, 1.29) (p-trend=0.002).

LIMITATIONS

Information on tinnitus and analgesic use was self-reported. Information on indications for analgesic use was not available. Studies in non-White women and men are needed.

CONCLUSION

The risk of developing persistent tinnitus was not elevated among frequent low-dose aspirin users. Among younger women, frequent moderate-dose aspirin use was associated with higher risk. Frequent NSAID use and frequent acetaminophen use were associated with higher risk of incident persistent tinnitus among all women, and the magnitude of the risks tended to be greater with increasing frequency of use. Our results suggest analgesic users are at higher risk for developing tinnitus and may provide insight into the precipitants of this challenging disorder, but additional investigation to determine whether there is a causal association is needed.

Invariant structural and functional brain regions associated with tinnitus: A meta-analysis

Tinnitus is a common, functionally disabling condition of often unknown etiology. Neuroimaging research to better understand tinnitus is emerging but remains limited in scope. Voxel-based physiology (VBP) studies detect tinnitus-associated pathophysiology by group-wise contrast (tinnitus vs controls) of resting-state indices of hemodynamics, metabolism, and neurovascular coupling. Voxel-based morphometry (VBM) detects tinnitus-associated neurodegeneration by group-wise contrast of structural MRI. Both VBP and VBM studies routinely report results as atlas-referenced coordinates, suitable for coordinate-based meta-analysis (CBMA). Here, 17 resting-state VBP and 8 VBM reports of tinnitus-associated regional alterations were meta-analyzed using activation likelihood estimation (ALE). Acknowledging the need for data-driven insights, ALEs were performed at two levels of statistical rigor: corrected for multiple comparisons and uncorrected. The corrected ALE applied cluster-level inference thresholding by intensity (z-score > 1.96; p < 0.05) followed by family-wise error correction for multiple comparisons (p < .05, 1000 permutations) and fail-safe correction for missing data. The corrected analysis identified one significant cluster comprising five foci in the posterior cingulate gyrus and precuneus, that is, not within the primary or secondary auditory cortices. The uncorrected ALE identified additional regions within auditory and cognitive processing networks. Taken together, tinnitus is likely a dysfunction of regions spanning multiple canonical networks that may serve to increase individuals’ interoceptive awareness of the tinnitus sound, decrease capacity to switch cognitive sets, and prevent behavioral and cognitive attention to other stimuli. It is noteworthy that the most robust tinnitus-related abnormalities are not in the auditory system, contradicting collective findings of task-activation literature in tinnitus.

Comparison of two behavioral tests for tinnitus assessment in mice

Animal research focused on chronic tinnitus associated with noise-induced hearing loss can be expensive and time-consuming as a result of the behavioral training required. Although there exist a number of behavioral tests for tinnitus; there have been few formal direct comparisons of these tests. Here, we evaluated animals in two different tinnitus assessment methods. CBA/CaJ mice were trained in an operant conditioning, active avoidance (AA) test, and a reflexive, gap-induced pre-pulse inhibition of acoustic startle (GPIAS) test, or both. Tinnitus was induced in awake mice by unilateral continuous sound exposure using a 2-kHz- or 12 octave-wide noise centered at 16 kHz and presented at 113- or 116-dB SPL. Tinnitus was assessed 8 weeks after sound overexposure. Most mice had evidence of tinnitus behavior in at least one of the two behaviors. Of the mice evaluated in AA, over half (55%) had tinnitus positive behavior. In GPIAS, fewer animals (13%) were positive than were identified using the AA test. Few mice were positive in both tests (10%), and only one was positive for tinnitus behavior at the same spectral frequency in both tests. When the association between tinnitus behavior and spontaneous activity recorded in the inferior colliculus was compared, animals with tinnitus behavior in AA exhibited increased spontaneous activity, while those positive in GPIAS did not. Thus, it appears that operant conditioning tests, like AA, maybe more reliable and accurate tests for tinnitus than reflexive tests.

Surface-based functional metrics and auditory cortex characteristics in chronic tinnitus

Abnormal auditory cortex (AC) neuronal activity is thought to be a primary cause of the auditory disturbances perceived by individuals suffering from tinnitus. The present study was designed to test that possibility by evaluating auditory cortical characteristics (volume, curvature, surface area, thickness) and surface-based functional metrics in chronic tinnitus patients. In total, 63 chronic tinnitus patients and 36 age-, sex- and education level-matched healthy control (HC) patients were enrolled in this study. Hearing levels in these two groups were comparable, and following magnetic resonance imaging (MRI) of these individuals, the DPABISurf software was used to compute cerebral cortex curvature, thickness, and surface area as well as surface-based functional metrics. The Tinnitus Handicap Inventory (THI), Tinnitus Handicap Questionary (THQ), and Visual Analogue Scales (VAS) were used to gauge participant tinnitus severity, while correlation analyses were conducted to evaluate associations between these different analyzed parameters. A significant increase in the regional homogeneity (ReHo) of the right secondary AC was detected in the tinnitus group relative to the HC group. There were also significant reductions in the cortical volume and surface area of the right secondary AC in the tinnitus group relative to the HC group (all P < 0.05). In addition, significant negative correlations between tinnitus pitch and the cortical area and volume of the right secondary AC were observed in the tinnitus group.

A Review on Peripheral Tinnitus, Causes, and Treatments from the Perspective of Autophagy

Tinnitus is the perception of phantom noise without any external auditory sources. The degeneration of the function or activity of the peripheral or central auditory nervous systems is one of the causes of tinnitus. This damage has numerous causes, such as loud noise, aging, and ototoxicity. All these sources excite the cells of the auditory pathway, producing reactive oxygen species that leads to the death of sensory neural hair cells. This causes involuntary movement of the tectorial membrane, resulting in the buzzing noise characteristic of tinnitus. Autophagy is an evolutionarily conserved catabolic scavenging activity inside a cell that has evolved as a cell survival mechanism. Numerous studies have demonstrated the effect of autophagy against oxidative stress, which is one of the reasons for cell excitation. This review compiles several studies that highlight the role of autophagy in protecting sensory neural hair cells against oxidative stress-induced damage. This could facilitate the development of strategies to treat tinnitus by activating autophagy.

Small molecule modulation of the large-conductance calcium-activated potassium channel suppresses salicylate-induced tinnitus in mice

Tinnitus is the phantom perception of sound that has no external source. A neurological signature of tinnitus, and the frequently associated hyperacusis, is an imbalance between excitatory and inhibitory activity in the central auditory system (CAS), leading to dysregulated network excitability. The large conductance, calcium-activated potassium (BK) channel is a key player in pre- and post-synaptic excitability through its mediation of K⁺ currents. Changes in BK channel activity are associated with aberrant network activity in sensory regions of the CNS, raising the possibility that BK channel modulation could regulate activity associated with tinnitus and hyperacusis. To test whether BK channel openers are able to suppress biomarkers of drug-induced tinnitus and hyperacusis, the 1,3,4 oxadiazole BMS-191011 was given to young adult CBA mice that had been administered 250 mg/kg sodium salicylate (SS). Systemic treatment with BMS-191011 reduced behavioral manifestations of SS-induced tinnitus, but not hyperacusis, probed via the gap-in-noise startle response method. Systemic BMS-191011 treatment did not influence SS-induced increases in auditory brainstem response functions, but local application at the inferior colliculus did reverse SS-suppressed spontaneous activity, particularly in the frequency region of the tinnitus percept. Thus, action of BMS-191011 in the inferior colliculus may contribute to the reduction in behaviorally measured tinnitus. Together, these findings support the utility of BK channel openers in reducing central auditory processing changes associated with the formation of the tinnitus percept.

The effects of photobiomodulation therapy in individuals with tinnitus and without hearing loss

To verify the effect of photobiomodulation therapy (PBMT) in individuals with chronic tinnitus without hearing loss, 20 patients who met the inclusion criteria were randomly divided into group 1: active low-level laser (LLL) and group 2: equipment without laser (placebo). Upon anamnesis, data collection, and audiological exams, the Tinnitus Handicap Inventory (THI) and the Visual-Analog Scale (EVA) were applied to measure the level of discomfort with tinnitus and the level of discomfort before and after laser treatment. The protocol used included 12 active LLL sessions for group 1 and not active for group 2, varying red and infrared wavelengths. There was a reduction in the disadvantage of individuals with tinnitus after the intervention and between the initial and final sessions, regardless of the intervention, although group 1 showed a greater reduction than group 2, regardless of point in time of assessment and number of session. There was no statistical difference as to group and point in time for the high-frequency audiometry and acuphenometry outcomes. Individuals with chronic tinnitus reduced the complaint, regardless of point in time and group of intervention; however, the group that received PBMT improved the level of satisfaction, regardless of point in time of assessment and number of session.

The Interrelationship of Tinnitus and Hearing Loss Secondary to Age, Noise Exposure, and Traumatic Brain Injury

OBJECTIVE

Tinnitus has been the No. 1 disability at the Veteran Administration for the last 15 years, yet its interaction with hearing loss secondary to etiologies such as age, noise trauma, and traumatic brain injuries remains poorly characterized. Our objective was to analyze hearing loss and tinnitus, including audiogram data, of the Million Veteran Program within the context of military exposures in an aging population.

DESIGN

Health records, questionnaires, audiograms, and military data were aggregated for 758,005 Veteran participants in the Million Veteran Program 2011 to 2020, with relative risks (RR) calculated for ancestries, sex, hearing loss and military exposures such as combat, blast, and military era served. A multivariate model with significant demographic measures and exposures was then analyzed. Next, audiogram data stratified by sex were compared for those with and without tinnitus by two methods: first, mean thresholds at standard frequencies were compared to thresholds adjusted per ISO 7029:2000E age and sex formulae. Second, levels for those ≤40 years of age were compared with those 41 and older. Finally, a proportional hazards model was examined to ascertain the timing between the onset of tinnitus and hearing loss, calculated separately for electronic health record diagnoses (ICD) and self-report.

RESULTS

Tinnitus was either self-reported, diagnosed, or both in 37.5% (95% CI, 37.4 to 37.6), mean age 61.5 (95% CI, 61.4 to 61.5), range 18 to 112 years. Those with hearing loss were 4.15 times (95% CI, 4.12 to 4.15) as likely to have tinnitus. Americans of African descent were less likely to manifest tinnitus (RR 0.61, 95% CI, 0.60 to 0.61), as were women (RR 0.65, 95% CI, 0.64 to 0.65). A multivariate model indicated a higher RR of 1.73 for traumatic brain injury (95% CI, 1.71 to 1.73) and daily combat noise exposure (1.17, 95% CI, 1.14 to 1.17) than age (0.998, 95% CI, 0.997 to 0.998). Subjects ≤40 years of age had small but significantly elevated hearing thresholds through all standard frequencies compared to Veterans without tinnitus, and the effect of tinnitus on hearing thresholds diminished with age. In the hazard model, those >40 with new onset of tinnitus were at risk for hearing loss sooner and with greater incidence than those who were younger. The rate of hearing loss following tinnitus approached 100%. In contrast, only approximately 50% of those who self-reported hearing loss initially were at risk for later hearing loss, in contrast to ICD comparison, where those with ICD of hearing loss were more likely to sustain an ICD of tinnitus subsequently.

CONCLUSIONS

Evidence suggests that the occurrence of tinnitus in the military is more closely related to environmental exposures than to aging. The finding that tinnitus affects hearing frequencies across the audiogram spectrum suggests an acoustic injury independent of tonotopicity. Particularly for males >40, tinnitus may be a harbinger of audiologic damage predictive of later hearing loss.

Characteristics of Kundalini-Related Sensory, Motor, and Affective Experiences During Tantric Yoga Meditation

Traditional spiritual literature contains rich anecdotal reports of spontaneously arising experiences occurring during meditation practice, but formal investigation of such experiences is limited. Previous work has sometimes related spontaneous experiences to the Indian traditional contemplative concept of kundalini. Historically, descriptions of kundalini come out of Tantric schools of Yoga, where it has been described as a “rising energy” moving within the spinal column up to the brain. Spontaneous meditation experiences have previously been studied within Buddhist and Christian practices and within eclectic groups of contemplative practitioners. Prior explorations of kundalini have emphasized extreme experiences, sometimes having clinical consequences. We conducted a first such investigation of kundalini-related experiences within a sample of meditators from a single Tantric Yoga tradition (known as Ananda Marga) that emphasizes the role of kundalini. We developed a semi-structured questionnaire to conduct an exploratory pilot investigation of spontaneous sensory, motor and affective experiences during meditation practice. In addition to identifying the characteristics of subjective experiences, we measured quantity of meditation, supplemental practices, trait affect and trait mindfulness. We administered it to 80 volunteers at two Ananda Marga retreats. Among reported experiences, we found the highest prevalence for positive mood shifts, followed by motor and then sensory experiences. The frequency of spontaneous experiences was not related to the quantity of practiced meditation or trait measures of mindfulness and affect. Self-reports included multiple descriptions of rising sensations, sometimes being directly called kundalini. Experiences with rising sensations were complex and many included references to positive affect, including ecstatic qualities. There were also reports of spontaneous anomalous experiences. These experiences of rising sensations resemble prior clinical descriptions that were considered kundalini-related. The individuals who reported rising sensations could not be distinguished from other participants based on the incidence of experiences, quantity of meditation practice, or trait measures of mindfulness and affect. In contrast, greater amount of Tantric Yoga meditation practice was associated with greater positive affect, less negative affect and greater mindfulness. Further study of these exploratory findings and how they may be related to spiritual and well-being goals of meditation is warranted along with scientific investigation of purported kundalini phenomena.

Pulsatile tinnitus and imaging diagnosis. A case report

Tinnitus is the perception of sound in one or both ears when no external noise exists to cause that perception. It can be otological, neurological, drug-related, traumatic, due to exposure to high decibel levels, or associated with a vascular abnormality—the latter usually causing pulsatile tinnitus. We present the diagnostic image of a patient with pulsatile tinnitus with terminal plate dehiscence of the jugular bulb and review the diagnostic workup. Jugular bulb dehiscence is a venous variant that consists of an upper and lateral extension of the jugular bulb into the middle ear through a dehiscent sigmoid plate. It is the most common vascular anatomical variant of the petrous portion of the temporal bone. Imaging studies are essential for establishing a diagnosis and defining possible anatomical variants.

A Chinese Medicine Formula (Bushen Huoxue Tongluo) for the Treatment of Chronic Subjective Tinnitus: A Study Protocol for a Pilot, Assessor-Blinded, Randomized Clinical Trial

Background: Tinnitus is a common problem worldwide. There is still no effective method to cure it. Traditional Chinese medicine (TCM) may be a potentially effective treatment approach for tinnitus. However, there is still no clinical trial with scientifically rigorous methodology to evaluate the treatment effect of TCM for tinnitus. Therefore, we propose a pilot study to inform the feasibility of a future full-scale RCT to establish the efficacy of TCM formula for tinnitus. Objectives: The aim of this study is to determine the feasibility of a full-scale RCT and explore whether a TCM formula (BHT) has an additional effect on improving tinnitus when compared to informative counseling alone. Design: An assessor-blinded, randomized, controlled clinical trial is used. Participants: Twenty-four patients with chronic subjective tinnitus will be enrolled. Interventions: The patients will be allocated randomly to receive a TCM formula (BHT, Bushen Huoxue Tongluo) and informative counseling or informative counseling alone. The oral BHT herbal granules will be taken twice per day continuously for 8 weeks. Main outcome measures: The primary outcomes include recruitment rate, intervention completion rate, and data completion rate to evaluate the feasibility. The secondary outcomes include Tinnitus Handicap Inventory, tinnitus functional index, tinnitus sensation level, self-rated visual analogue scale on tinnitus loudness and annoyance, Pittsburgh Sleep Quality Index, Hospital Anxiety and Depression Scale, and adverse event. The outcome measures will be collected at baseline, end of treatment, and 4-week follow-up. Discussion: This trial is currently ongoing and is recruiting patients. The expected study results will find some preliminary evidence about the clinical effectiveness of BHT on chronic tinnitus and will also determine if it is feasible to conduct a full-scale RCT of BHT and identify the necessary changes to the protocol if possible.

Toward a Multidimensional Understanding of Misophonia Using Cluster-Based Phenotyping

Misophonia is a condition characterized by hypersensitivity and strong emotional reactivity to specific auditory stimuli. Misophonia clinical presentations are relatively complex and reflect individualized experiences across clinical populations. Like some overlapping neurodevelopmental and neuropsychiatric disorders, misophonia is potentially syndromic where symptom patterns rather than any one symptom contribute to diagnosis. The current study conducted an exploratory k-means cluster analysis to evaluate symptom presentation in a non-clinical sample of young adult undergraduate students (N = 343). Individuals participated in a self-report spectrum characteristics survey indexing misophonia, tinnitus severity, sensory hypersensitivity, and social and psychiatric symptoms. Results supported a three-cluster solution that split participants on symptom presentation: cluster 1 presented with more severe misophonia symptoms but few overlapping formally diagnosed psychiatric co-occurring conditions; cluster 3 was characterized by a more nuanced clinical presentation of misophonia with broad-band sensory hypersensitivities, tinnitus, and increased incidence of social processing and psychiatric symptoms, and cluster 2 was relatively unaffected by misophonia or other sensitivities. Clustering results illustrate the spectrum characteristics of misophonia where symptom patterns range from more “pure” form misophonia to presentations that involve more broad-range sensory-related and psychiatric symptoms. Subgroups of individuals with misophonia may characterize differential neuropsychiatric risk patterns and stem from potentially different causative factors, highlighting the importance of exploring misophonia as a multidimensional condition of complex etiology.