Tinnitus loudness and the severity of insomnia: a mediation analysis

Evaluation of factors predicting tinnitus outcomes following cochlear implantation: Protocol for a prospective quasi-experimental study

Cochlear implantation is an effective intervention to restore useful aspects of hearing function in adults with severe-to-profound hearing loss. Tinnitus, the perception of sound in the absence of an external source, is common in people with severe-to-profound hearing loss. Existing evidence suggests cochlear implantation may be effective in reducing the negative impact of tinnitus in this population. However, this is contradicted by data suggesting that up to half of cochlear implant recipients experience tinnitus, and that some of these patients who did not have tinnitus before cochlear implantation experience it after surgery or cochlear implant activation. Most evidence on the effects of cochlear implantation on tinnitus comes from secondary data in cochlear implant studies primarily concerned with hearing-related outcomes. Hence, the quality of the evidence for effects on tinnitus is low and not suitable to inform clinical recommendations or decision-making. This study will systematically collect data on tinnitus and tinnitus-related outcomes from patients at multiple points during the cochlear implant pathway to characterise changes in tinnitus. This will improve our understanding of the effects of cochlear implantation for tinnitus in adults with severe to profound hearing loss and inform the design of clinical trials of cochlear implantation for tinnitus.

The Association Between Tinnitus Sensation-Level Loudness and Sleep Quality in Patients With Subjective Consecutive Tinnitus: A Mediation Analysis

PURPOSE

So far, there have been no in-depth analyses of the connection between tinnitus sensation-level loudness and sleep quality. Accordingly, the present study was formulated as a mediation analysis focused on exploring this relationship.

METHOD

Overall, 1,255 adults with consecutive subjective tinnitus who had sought outpatient treatment were enrolled in the present study.

RESULTS

Direct effects of tinnitus sensation-level loudness on sleep quality were not statistically significant (95% confidence intervals [CI] include zero), as measured by the point estimate, -0.016. However, the 95% CI for indirect effects did not include zero when assessing the Self-Rating Anxiety Scale (SAS) scores, the Self-Rating Depression Scale (SDS) scores, the visual analogue scale (VAS) scores, and self-reported tinnitus annoyance.

CONCLUSIONS

These results suggest that tinnitus sensation-level loudness does not directly have an effect on sleep quality. However, it indirectly impacts sleep quality, mediated by SAS scores, SDS scores, the impact of tinnitus on life measured using the VAS, and self-reported tinnitus annoyance. As such, alleviating anxiety and depression in patients with tinnitus may result in reductions in their insomnia even if there is no reduction in tinnitus loudness. Importantly, otolaryngologists and other clinicians treating tinnitus should refer patients with tinnitus suffering from insomnia with comorbid depression or anxiety for appropriate psychological and/or psychiatric treatment.

Confirmatory factor analysis of the Tinnitus Impact Questionnaire using data from patients seeking help for tinnitus alone or tinnitus combined with hyperacusis

A confirmatory factor analysis (CFA) of the Tinnitus Impact Questionnaire (TIQ) was performed. In contrast to commonly used tinnitus questionnaires, the TIQ is intended solely to assess the impact of tinnitus by not including items related to hearing loss or tinnitus loudness. This was a psychometric study based on a retrospective cross-sectional analysis of clinical data. Data were available for 155 new patients who had attended a tinnitus and hyperacusis clinic in the UK within a five-month period and had completed the TIQ. The mean age was 54 years (standard deviation = 14 years). The TIQ demonstrated good internal consistency, with Cronbach's α = 0.84 and McDonald's ω = 0.89. CFA showed that two items of the TIQ had low factor loadings for both one-factor and two-factor models and their scores showed low correlations with scores for other items. Bi-factor analysis gave a better fit, indicated by a relative chi-square (χ2) of 18.5, a Root-Mean Square Error of Approximation (RMSEA) of 0.103, a Comparative Fit Index (CFI) of 0.97, a Tucker Lewis Index (TLI) of 0.92, and a Standardized Root-Mean Residual (SPMR) of 0.038. Total TIQ scores were moderately correlated with scores for the Visual Analogue Scale of effect of tinnitus on life and the Screening for Anxiety and Depression-Tinnitus questionnaire, supporting the convergent validity of the TIQ. The TIQ score was not correlated with the pure-tone average hearing threshold, indicating discriminant validity. A multiple-causes multiple-indicator (MIMIC) model showed no influences of age, gender or hearing status on TIQ item scores. The TIQ is an internally consistent tool. CFA suggests a bi-factor model with sufficient unidimensionality to support the use of the overall TIQ score for assessing the impact of tinnitus. TIQ scores are distinct from the impact of hearing impairment among patients who have tinnitus combined with hearing loss.

How people with tinnitus-related insomnia experience group CBT-for-insomnia (CBTi): a thematic analysis

Objective: Although insomnia often compounds tinnitus, sleeping problems in people experiencing tinnitus are rarely treated. This study investigates the experiences of participants receiving Cognitive Behavioural Therapy for insomnia (CBTi) as part of a randomised controlled trial for managing tinnitus-related insomnia. The aim of this study is to gain detailed insight into participants' perceptions and experiences of this treatment.Design: Semi-structured interviews were conducted via phone or in-person by one of the two clinical psychologists who facilitated the CBTi sessions. Reflexive thematic analysis with semantic inductive approach was used for analysis to keep the research question theoretically flexible.Study samples: Eight participants (three females, age range 32-69 years) were interviewed six months after CBTi completion.Results: Three superordinate themes were identified: "Common humanity and transcending individual distress," "Changing the things I can" and "Accepting the things I cannot change." The group environment helped participants to normalise their experiences. Reliable tinnitus/sleep information and robust behavioural change techniques helped participants to respond and relate to their condition differently.Conclusion: Generally, participants reported long-term benefits from CBTi to treat tinnitus-related insomnia, particularly increased confidence, and getting on with life. CBTi is multi-component, so clinicians need to respond to individual preferences and lifestyles.

Telehealth in treating tinnitus: a systematic review and meta-analysis

OBJECTIVE

Treatment for tinnitus focuses on supportive therapies. Long waiting times in the National Health Service encourage telemedicine options as an alternative. This study aimed to review the literature on telemedicine in the management of tinnitus and analyse its impact on the burden of tinnitus, long-term, anxiety, depression, insomnia and quality of life.

METHOD

PubMed, Embase, Cochrane Library, Google Scholar, Scopus and Web of Science were searched. English randomised, controlled trials with adult participants suffering from tinnitus were included. A random effects model looking at standardised mean differences between intervention and control groups was utilised.

RESULTS

Eleven randomised, controlled trials were included. Nine studies looked at internet-based cognitive behavioural therapy. A z-value of 9.87 (p < 0.00001; I2 = 21 per cent) showed telemedicine approaches may be better at reducing tinnitus burden compared with passive controls.

CONCLUSION

Telemedicine options have multiple benefits, but more research will be needed to conclusively say they are better than alternatives.

Psychometric evaluation of the tinnitus impact questionnaire using patients seeking help for tinnitus or tinnitus with hyperacusis

OBJECTIVE

To evaluate the psychometric properties of the Tinnitus Impact Questionnaire (TIQ), whose questions focus on assessing the impact of tinnitus on the patient's day to day activities, mood, and sleep, and not on hearing difficulties.

DESIGN

This was a retrospective cross-sectional study.

STUDY SAMPLE

Data were included for 172 adult patients who attended a tinnitus and hyperacusis clinic in the UK within a six-month period and who had completed the TIQ.

RESULTS

Two items whose scores were very highly correlated with those for other items were removed, leaving seven items. Exploratory factor analysis suggested a single factor for the TIQ. A multiple causes multiple indicator model showed significant but very small direct effects of age on TIQ scores for two items, after adjustment for gender. The TIQ had excellent internal consistency, with Cronbach's alpha = 0.89. The total TIQ score was moderately to strongly correlated with scores for the Tinnitus Handicap Inventory, Screening for Anxiety and Depression-Tinnitus questionnaire, Hyperacusis Questionnaire, and Hyperacusis Impact Questionnaire, indicating convergent validity. The TIQ score was weakly correlated with the pure-tone average hearing threshold, indicating discriminant validity.

CONCLUSIONS

The TIQ is a brief, valid and internally consistent questionnaire for assessing the impact of tinnitus.

Cognitive–behavioral factors in tinnitus-related insomnia

Background

A significant proportion of individuals with distressing tinnitus also report insomnia. Limited, but emerging, evidence suggests that tinnitus-related insomnia cannot be explained only by the presence of tinnitus and that sleep-related cognitive–behavioral processes may play a key role in exacerbating tinnitus-related insomnia.

Objectives

This study aimed to assess whether sleep-related cognitions and behaviors believed to maintain insomnia disorder are present in individuals with tinnitus-related insomnia.

Methods

This between-groups study recruited 180 participants online for four groups: tinnitus-related insomnia (N = 49), insomnia disorder without tinnitus (N = 34), tinnitus sufferers who are good sleepers (N = 38), and controls (N = 59). They completed questionnaires assessing insomnia severity, sleep-related cognitions and behaviors, sleep quality, anxiety, and depression. People with tinnitus completed a measure of tinnitus severity and rated the loudness of their tinnitus on a subjective measure.

Results

Linear regression demonstrated that group significantly predicted sleep related thoughts and behaviors, and sleep quality. Pairwise comparisons showed that the tinnitus-related insomnia group had significantly greater insomnia-related thoughts and behaviors and significantly worse sleep quality than tinnitus-good sleepers. No differences were seen between the tinnitus-related insomnia and the insomnia groups. The tinnitus-related insomnia group had significantly higher depression, anxiety, and tinnitus distress than tinnitus-good sleepers.

Conclusion

Findings suggest that tinnitus-related insomnia may be maintained by cognitive–behavioral processes similar to those found in insomnia disorder. Such processes are more important than tinnitus severity when understanding sleep disturbance. People with tinnitus-related insomnia may benefit from treatments such as cognitive–behavioral therapy for insomnia.

The association between stress, emotional states, and tinnitus: a mini-review

Extensive literature supporting the view of tinnitus induced stress in patients is available. However, limited evidence has been produced studying the opposite, that is, does stress cause tinnitus? The hypothalamus pituitary adrenal axis, one of the main neuroendocrine systems involved in stress response, is commonly disturbed in tinnitus patients. Patients with chronic tinnitus have been shown to develop abnormal responses to psycho-social stress, where the hypothalamus pituitary adrenal axis response is weaker and delayed, suggesting chronic stress contributes to the development of chronic tinnitus. The sympathetic branch of the autonomic nervous system also plays a major role in stress response and its chronic hyperactivity seems to be involved in developing tinnitus. Psycho-social stress has been shown to share the same probability of developing tinnitus as occupational noise and contributes to worsening tinnitus. Additionally, exposure to high stress levels and occupational noise doubles the likelihood of developing tinnitus. Interestingly, short-term stress has been shown to protect the cochlea in animals, but chronic stress exposure has negative consequences. Emotional stress also worsens pre-existing tinnitus and is identified as an important indicator of tinnitus severity. Although there is limited body of literature, stress does seem to play a vital role in the development of tinnitus. This review aims to highlight the association between stress, emotional states, and the development of tinnitus while also addressing the neural and hormonal pathways involved.

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.

The Efficacy and Safety of Acupuncture for Tinnitus-Associated Insomnia: A Protocol for a Systematic Review and Meta-Analysis

Background

Tinnitus accounts for a significant proportion of the factors that cause insomnia, and insomnia, in turn, aggravates tinnitus. Given that tinnitus and insomnia have a bidirectional relationship, tinnitus-associated insomnia is prevalent. Nonetheless, current treatments including medication and psychological therapies for tinnitus-associated insomnia do not yield satisfactory efficacy, thereby making it challenging to manage. Although acupuncture is a potentially effective treatment option, the current evidence on the efficacy and safety of acupuncture for tinnitus-associated insomnia remains inconclusive. Therefore, this systematic review and analysis protocol aims to investigate whether acupuncture is beneficial for tinnitus-associated insomnia with an acceptable safety profile.

Methods

Nine mainstream English-language and Chinese-language databases will be searched to include qualified RCTs and meta-analyses will be conducted by combining extracted data using RevMan 5.3. The risk of bias 2.0 tool recommended by Cochrane will be adopted to evaluate the methodological quality of the included RCTs. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach will be utilized to appraise the strength and certainty of evidence. Where available, we will also perform sensitivity analyses, publication bias and subgroup analysis.

Discussion

Expected results from our systematic review and meta-analysis will verify the efficacy and safety of acupuncture in tinnitus-associated insomnia. The evidence generated by this review will help patients and clinicians make informed treatment decisions.

Self-Reported Tinnitus Severity Prior to and During the COVID-19 Lockdown in the United Kingdom

BACKGROUND AND PURPOSE

 The aim of this study was to assess whether the severity of tinnitus, as measured using ratings of tinnitus loudness, annoyance, and effect on life, was influenced by the lockdown related to the coronavirus disease 2019 (COVID-19) pandemic.

RESEARCH DESIGN

 This was a retrospective study.

STUDY SAMPLE

 The data for 105 consecutive patients who were seen at a tinnitus clinic in an audiology department in the United Kingdom during the COVID-19 lockdown between April and June 2020 and 123 patients seen in the same period of the previous year, prior to the COVID-19 pandemic were included.

DATA COLLECTION

 Demographic data for the patients, results of their pure-tone audiometry, and their score on visual analog scale (VAS) of tinnitus loudness, annoyance, and effect on life were imported from their records held at the audiology department. This was a retrospective survey comparing ratings on the VAS of tinnitus loudness, annoyance, and effect on life for consecutive patients seen during the COVID-19 lockdown and consecutive patients seen in the same period of the previous year, prior to the COVID-19 pandemic. Patients seen prior to lockdown used a pen and paper version of the VAS, while the patients who were assessed during the COVID-19 lockdown used an adapted version of the VAS, via telephone. All patients were seeking help for their tinnitus for the first time.

RESULTS

 The mean scores for tinnitus loudness, annoyance, and effect on life did not differ significantly for the groups seen prior to and during lockdown.

CONCLUSION

 Any changes in psychological well-being or stress produced by the lockdown did not significantly affect ratings of the severity of tinnitus.

Internal Consistency and Convergent Validity of the Inventory of Hyperacusis Symptoms

OBJECTIVES

The aim was to assess the internal consistency and convergent and discriminant validity of a new questionnaire for hyperacusis, the Inventory of Hyperacusis Symptoms (IHS; Greenberg & Carlos 2018), using a clinical population.

DESIGN

This was a retrospective study. Data were gathered from the records of 100 consecutive patients who sought help for tinnitus and/or hyperacusis from an audiology clinic in the United Kingdom. The average age of the patients was 55 years (SD = 13 years). Audiological measures were the pure-tone average threshold (PTA) and uncomfortable loudness levels (ULL). Questionnaires administered were: IHS, Tinnitus Handicap Inventory (THI), Hyperacusis Questionnaire (HQ), Insomnia Severity Index, Generalized Anxiety Disorder, and Patient Health Questionnaire-9.

RESULTS

Cronbach's alpha for the 25-item IHS questionnaire was 0.96. Neither the total IHS score nor scores for any of its five subscales were correlated with the PTA of the better or worse ear. This supports the discriminant validity of the IHS, as hyperacusis is thought to be independent of the PTA. There were moderately strong correlations between IHS total scores and scores for the HQ, Tinnitus Handicap Inventory, Generalized Anxiety Disorder, and Patient Health Questionnaire-9, with r = 0.58, 0.58, 0.61, 0.54, respectively. Thus, although IHS scores may reflect hyperacusis itself, they may also reflect the coexistence of tinnitus, anxiety, and depression. The total score on the IHS was significantly different between patients with and without hyperacusis (as diagnosed based on ULLs or HQ scores). Using the HQ score as a reference, the area under the receiver operating characteristic for the IHS was 0.80 (95% confidence interval = 0.71 to 0.89) and the cutoff point of the IHS with highest overall accuracy was 56/100. The corresponding sensitivity and specificity were 74% and 82%.

CONCLUSIONS

The IHS has good internal consistency and reasonably high convergent validity, as indicated by the relationship of IHS scores to HQ scores and ULLs, but IHS scores may also partly reflect the co-occurrence of tinnitus, anxiety, and depression. We propose an IHS cutoff score of 56 instead of 69 for diagnosing hyperacusis.

A population-based case-control study of the association between cervical spondylosis and tinnitus

OBJECTIVE

This population-based study aimed to study the association between tinnitus and cervical spondylosis.

DESIGN

A case-control study.

STUDY SAMPLE

We retrieved data from the Taiwan Longitudinal Health Insurance Database. We identified 2465 patients with tinnitus (cases) and 7395 comparison patients by propensity score matching. Multivariable logistic regressions were conducted to estimate the odds (OR) of a diagnosis of cervical spondylosis preceding the tinnitus diagnosis relative to controls.

RESULTS

We found that 1596 (16.19%) of 9860 sample patients had received a diagnosis of cervical spondylosis before the index date, significantly different between the tinnitus group and control group (17.20% vs. 15.85%, p < 0.001). Logistic regression analysis showed an adjusted OR for prior cervical spondylosis of 1.235 for cases vs. controls (95% confidence interval [CI]: 1.088-1.402). Further, the adjusted ORs were 1.246 (95% CI: 1.041-1.491) and 1.356 (95% CI: 1.016-1.811), respectively, among patients aged 45 ∼ 64 and >64 groups. No difference in cervical spondylosis likelihood between cases and controls was found among patients aged 18 ∼ 44 groups.

CONCLUSIONS

In conclusion, the study shows a positive association between cervical spondylosis and tinnitus. The findings call for greater awareness among physicians about a possible somatosensory component of cervical spine function which may contribute to tinnitus.

Preliminary Examination of the Incidence of and Factors Related to Hearing Tinnitus in Dreams

BACKGROUND AND PURPOSE

 The aim of this study was to assess the incidence of the perception of tinnitus in dreams among patients seeking help for tinnitus and/or hyperacusis and to assess whether this is related to the severity of tinnitus and/or hyperacusis.

RESEARCH DESIGN

 This was a retrospective study.

STUDY SAMPLE

 The data for 148 consecutive adult patients who attended a tinnitus/hyperacusis clinic in the United Kingdom were included. The average age of the patients was 56 years (standard deviation [SD] = 15 years).

DATA COLLECTION

 Data were collected retrospectively from their records held at the audiology department. Audiological measures were pure-tone audiometry and uncomfortable loudness levels. Questionnaires administered were: Tinnitus Handicap Inventory (THI), Hyperacusis Questionnaire, Insomnia Severity Index, Visual Analogue Scale (VAS) of tinnitus loudness, annoyance, and effect on life, Generalized Anxiety Disorder, and Patient Health Questionnaire. Patients were also asked "If you dream have you ever perceived tinnitus in your dreams?"

RESULTS

 Five percent of patients (7/148) reported hearing tinnitus in their dreams. There was a nonsignificant trend for patients who reported hearing tinnitus in their dreams to be younger (mean age = 46 years, SD = 15 years) than those who did not (mean age = 57 years, SD = 15 years). The mean scores for the THI and VAS for effect of tinnitus on life were significantly higher (worse) for patients who reported hearing tinnitus in their dreams than for those who did not.

CONCLUSION

 A small proportion of patients reported hearing tinnitus in their dreams and this was associated with higher tinnitus handicap as measured via the THI and more effect of tinnitus on life as measured via the VAS. These preliminary results may indicate that those who are greatly affected by their tinnitus are more likely to hear it in their dreams or to be woken by it. Future studies should use methods that can be used to reliably assess if and when tinnitus is perceived during the sleep cycle, using more physiological measures and testing a wider population.

An exploration of psychological symptom-based phenotyping of adult cochlear implant users with and without tinnitus using a machine learning approach

The identification of phenotypes within populations with troublesome tinnitus is an important step towards individualizing tinnitus treatments to achieve optimal outcomes. However, previous application of clustering algorithms has called into question the existence of distinct tinnitus-related phenotypes. In this study, we attempted to characterize patients' symptom-based phenotypes as subpopulations in a Gaussian mixture model (GMM), and subsequently performed a comparison with tinnitus reporting. We were able to effectively evaluate the statistical models using cross-validation to establish the number of phenotypes in the cohort, or a lack thereof. We examined a cohort of adult cochlear implant (CI) users, a patient group for which a relation between psychological symptoms (anxiety, depression, or insomnia) and trouble tinnitus has previously been shown. Accordingly, individual item scores on the Hospital Anxiety and Depression Scale (HADS; 14 items) and the Insomnia Severity Index (ISI; 7 items) were selected as features for training the GMM. The resulting model indicated four symptom-based subpopulations, some primarily linked to one major symptom (e.g., anxiety), and others linked to varying severity across all three symptoms. The presence of tinnitus was self-reported and tinnitus-related handicap was characterized using the Tinnitus Handicap Inventory. Specific symptom profiles were found to be significantly associated with CI users' tinnitus characteristics. GMMs are a promising machine learning tool for identifying psychological symptom-based phenotypes, which may be relevant to determining appropriate tinnitus treatment.

Auditory experience, for a certain duration, is a prerequisite for tinnitus: lessons from subjects with unilateral tinnitus in the better-hearing ear

Tinnitus has traditionally been considered an otologic disorder; however, recent advances in auditory neuroscience have shifted investigations toward the brain. The Bayesian brain model explains tinnitus as an auditory phantom percept. According to the model, the brain works to reduce environmental uncertainty, and thus the absence of auditory information due to hearing loss may cause auditory phantom percepts, i.e., tinnitus. As in animal studies, our recent human observational study revealed the absence of ipsilesional tinnitus in subjects with congenital single-sided deafness, suggesting that auditory experience is a prerequisite for the generation of tinnitus. Prompted by anecdotal cases, we hypothesized that subjects with acquired hearing loss would not develop tinnitus if their duration of auditory experience was not sufficiently long. We retrospectively enrolled 22 subjects with acquired asymmetric hearing loss and unilateral tinnitus in better ear (TBE). Twenty-two hearing threshold-matched controls with tinnitus in worse ear (TWE) were selected from our database of tinnitus patients. All 22 TBE subjects reported that their acquired hearing loss developed before the age of 20, and the reported duration of auditory deprivation in the ear without tinnitus in the TBE group was significantly longer than that of the TWE group. In other words, the TBE group with limited auditory experience in the worse ear did not develop tinnitus in the worse ear while subjects with enough auditory experiences in the worse ear developed ipsilesional tinnitus in the TWE group. These preliminary results support our hypothesis that both auditory experience itself, and an individually variable critical duration of auditory deprivation, are prerequisites for the generation of tinnitus.