The role of zinc in the treatment of tinnitus

Effectiveness of Tinnitan Duo® in Subjective Tinnitus with Emotional Affectation: A Prospective, Interventional Study

To assess the effectiveness of a food supplement (Tinnitan Duo®) containing 5-hydroxytryptophan, Ginkgo biloba, magnesium, melatonin, vitamin B5 and B6, and zinc at improving tinnitus response and intensity. Prospective, single-center interventional study including patients with subjective tinnitus and emotional affectation. The primary endpoint was the change in the Tinnitus Handicap Inventory (THI) total score and the emotional subscale after 3 months of treatment. Secondary endpoints were the change from baseline to month 3 in (1) the Tinnitus Distress Rating (TDR) scale, and (2) in hearing status, and the safety profile of patients throughout the study. Sixty-one patients were included, and 29 completed the study. The THI total score was significantly reduced after 3 months of treatment in the per-protocol (PP, all the patients with no major protocol deviations) and intention-to-treat (ITT) populations (-15.7 and -7.5, respectively; p = 0.001). The emotional subscale score significantly decreased after 3 months of treatment by -5.6 in the PP (p = 0.001) and by -2.6 in the ITT populations (p = 0.001). Perceived tinnitus loudness significantly decreased after 3 months of treatment (p = 0.001). The audiogram showed no significant changes in hearing status after 3 months of treatment. Of the five adverse events (AEs) reported, all were mild or moderate, and three were related to the study treatment (two headaches and one dizziness). This new food supplement was associated with an improved tinnitus-related emotional affectation and with a good safety profile.

The Effect of Antioxidant Supplementation in Patients with Tinnitus and Normal Hearing or Hearing Loss: A Randomized, Double-Blind, Placebo Controlled Trial

Tinnitus is the perception of sound in the absence of any external stimulus. Oxidative stress is possibly involved in its pathogenesis and a variety of antioxidant compounds have been studied as potential treatment approaches. The objective of the present study was to assess the effects of antioxidant supplementation in tinnitus patients. This is a randomized, double-blind, placebo-controlled clinical trial. Patients (N = 70) were randomly allocated to antioxidant supplementation (N = 35) or to placebo (N = 35) for a total of 3 months. Demographic, anthropometric, clinical, and nutritional data were collected. Serum total antioxidant capacity (TAC), oxidized LDL (oxLDL), and superoxide dismutase (SOD), tinnitus loudness, frequency, and minimum masking level (MML), and scores in Tinnitus Handicap Inventory questionnaire (THI), Tinnitus Functional Index (TFI), and Visual Analogue Scale (VAS) were evaluated at baseline and follow-up. Tinnitus loudness and MML significantly decreased from baseline to post measure (p < 0.001) only in the antioxidant group, the overall change being significantly different between the two groups post-intervention (p < 0.001). THI and VAS decreased only in the antioxidant group. Differences in changes in serum TAC, SOD, and oxLDL post-intervention were insignificant. In conclusion, antioxidant therapy seems to reduce the subjective discomfort and tinnitus intensity in tinnitus patients.

Effects of oral zinc supplementation on patients with noise-induced hearing loss associated tinnitus: A clinical trial

BACKGROUND

Zinc plays a vital antioxidant role in human metabolism. Recent studies have demonstrated a correlation between noise-induced hearing loss (NIHL) and oxidative injury; however, no investigation has focused specifically on the subgroup of NIHL associated tinnitus patients. We aimed to evaluate the effectiveness of zinc supplementation in treating NIHL associated tinnitus.

METHODS

Twenty patients with tinnitus and a typical NIHL audiogram (38 ears) were included in this study. Another 20 healthy subjects were used as the control group. A full medical history assessment was performed, and each subject underwent an otoscopic examination, basic audiologic evaluation, distortion product otoacoustic emissions (DPOAEs), tinnitus-match testing, Tinnitus Handicap Inventory (THI) and serum zinc level analyses. After 2 months of treatment with zinc, all tests were repeated.

RESULTS

There was a significant difference between pretreatment and post-treatment within the tinnitus group (73.6 vs. 84.6 μg/dl). The pre- and post-treatment difference in serum zinc was significantly higher in the young group (≦50 years) compared to the old group (19.4 ± 11.4 vs. 2.6 ± 9.2 μg/dl, respectively; p = 0.002). There were no statistically significant differences in hearing thresholds, speech reception thresholds, or tinnitus frequency and loudness results before and after treatment. In addition, 17 patients (85%) showed statistically significant improvement of THI-total scores post-treatment, from 38.3 to 30 (p = 0.024).

CONCLUSIONS

Zinc oral supplementation elevated serum zinc levels, especially in younger patients. THI scores improved significantly following zinc treatment in patients with NIHL associated tinnitus. However, no improvements in objective hearing parameters were observed.

Tinnitus: Prospects for Pharmacological Interventions With a Seesaw Model

Chronic tinnitus, the perception of lifelong constant ringing in ear, is one capital cause of disability in modern society. It is often present with various comorbid factors that severely affect quality of life, including insomnia, deficits in attention, anxiety, and depression. Currently, there are limited therapeutic treatments for alleviation of tinnitus. Tinnitus can involve a shift in neuronal excitation/inhibition (E/I) balance, which is largely modulated by ion channels and receptors. Thus, ongoing research is geared toward pharmaceutical approaches that modulate the function of ion channels and receptors. Here, we propose a seesaw model that delineates how tinnitus-related ion channels and receptors are involved in homeostatic E/I balance of neurons. This review provides a thorough account of our current mechanistic understanding of tinnitus and insight into future direction of drug development.

The Role of Trace Elements in Tinnitus

In this study, we aimed to investigate the role of three trace elements, namely, zinc, copper, and lead, in tinnitus by analyzing the serum level of copper and lead and both the serum and tissue level of zinc. Eighty patients, who applied to outpatient otolaryngology clinic with the complaints of having tinnitus, and 28 healthy volunteers were included. High-frequency audiometry was performed, and participants who had hearing loss according to the pure tone average were excluded; tinnitus frequency and loudness were determined and tinnitus reaction questionnaire scores were obtained from the patients. Of all the participants, serum zinc, copper, and lead values were measured; moreover, zinc levels were examined in hair samples. The levels of trace elements were compared between tinnitus and control groups. The level of copper was found to be significantly lower in the tinnitus group (p = 0.02), but there was no significant difference between the groups in terms of the levels of zinc, neither in serum nor in hair, and lead in serum (p > 0.05). The lack of trace elements, especially that of "zinc," have been doubted for the etiopathogenesis of tinnitus in the literature; however, we only found copper levels to be low in patients having tinnitus.

Zinc supplementation for tinnitus

BACKGROUND

Tinnitus is the perception of sound without external acoustic stimuli. Patients with severe tinnitus may have physical and psychological complaints and their tinnitus can cause deterioration in their quality of life. At present no specific therapy for tinnitus has been found to be satisfactory in all patients. In recent decades, a number of reports have suggested that oral zinc supplementation may be effective in the management of tinnitus. Since zinc has a role in cochlear physiology and in the synapses of the auditory system, there is a plausible mechanism of action for this treatment.

OBJECTIVES

To evaluate the effectiveness and safety of oral zinc supplementation in the management of patients with tinnitus.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the ENT Trials Register; Central Register of Controlled Trials (CENTRAL 2016, Issue 6); PubMed; EMBASE; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 July 2016.

SELECTION CRITERIA

Randomised controlled trials comparing zinc supplementation versus placebo in adults (18 years and over) with tinnitus.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures recommended by Cochrane. Our primary outcome measures were improvement in tinnitus severity and disability, measured by a validated tinnitus-specific questionnaire, and adverse effects. Secondary outcomes were quality of life, change in socioeconomic impact associated with work, change in anxiety and depression disorders, change in psychoacoustic parameters, change in tinnitus loudness, change in overall severity of tinnitus and change in thresholds on pure tone audiometry. We used GRADE to assess the quality of the evidence for each outcome; this is indicated in italics.

MAIN RESULTS

We included three trials involving a total of 209 participants. The studies were at moderate to high risk of bias. All included studies had differences in participant selection criteria, length of follow-up and outcome measurement, precluding a meta-analysis. The participants were all adults over 18 years with subjective tinnitus, but one study conducted in 2013 (n = 109) included only elderly patients. Improvement in tinnitus severity and disabilityOnly the study in elderly patients used a validated instrument (Tinnitus Handicap Questionnaire) for this primary outcome. The authors of this cross-over study did not report the results of the two phases separately and found no significant differences in the proportion of patients reporting tinnitus improvement at four months of follow-up: 5% (5/93) versus 2% (2/94) in the zinc and placebo groups, respectively (risk ratio (RR) 2.53, 95% confidence interval (CI) 0.50 to 12.70; very low-quality evidence).None of the included studies reported any significant adverse effects. Secondary outcomesFor the secondary outcome change in tinnitus loudness, one study reported no significant difference between the zinc and placebo groups after eight weeks: mean difference in tinnitus loudness -9.71 dB (95% CI -25.53 to 6.11; very low-quality evidence). Another study also measured tinnitus loudness but used a 0- to 100-point scale. The authors of this second study reported no significant difference between the zinc and placebo groups after four months: mean difference in tinnitus loudness rating scores 0.50 (95% CI -5.08 to 6.08; very low-quality evidence).Two studies used unvalidated instruments to assess tinnitus severity. One (with 50 participants) reported the severity of tinnitus using a non-validated scale (0 to 7 points) and found no significant difference in subjective tinnitus scores between the zinc and placebo groups at the end of eight weeks of follow-up (mean difference (MD) -1.41, 95% CI -2.97 to 0.15; very low-quality evidence). A third trial (n = 50) also evaluated the improvement of tinnitus using a non-validated instrument (a 0 to 10 scale: 10 = severe and unbearable tinnitus). In this study, after eight weeks there was no difference in the proportion of patients with improvement in their tinnitus, 8.7% (2/23) treated with zinc versus 8% (2/25) of those who received a placebo (RR 1.09, 95% CI 0.17 to 7.10, very low-quality evidence).None of the included studies reported any of our other secondary outcomes (quality of life, change in socioeconomic impact associated with work, change in anxiety and depression disorders, change in psychoacoustic parameters or change in thresholds on pure tone audiometry).

AUTHORS' CONCLUSIONS

We found no evidence that the use of oral zinc supplementation improves symptoms in adults with tinnitus.

Survey on the Effectiveness of Dietary Supplements to Treat Tinnitus

PURPOSE

We surveyed the benefit of dietary supplements to treat tinnitus and reported adverse effects.

METHOD

A website was created for people with tinnitus to complete a variety of questions.

RESULTS

The 1,788 subjects who responded to questionnaires came from 53 different countries; 413 (23.1%) reported taking supplements. No effect on tinnitus was reported in 70.7%, improvement in 19.0%, and worsening in 10.3%. Adverse effects were reported in 6% (n = 36), including bleeding, diarrhea, headache, and others. Supplements were reported to be helpful for sleep: melatonin (effect size, d = 1.228) and lipoflavonoid (d = 0.5244); emotional reactions: melatonin (d = 0.6138) and lipoflavonoid (d = 0.457); hearing: Ginkgo biloba (d = 0.3758); and concentration Ginkgo biloba (d = 0.3611). The positive, subjective reports should be interpreted cautiously; many might have reported a positive effect because they were committed to treatment and expected a benefit. Users of supplements were more likely to have loudness hyperacusis and to have a louder tinnitus.

CONCLUSIONS

The use of dietary supplements to treat tinnitus is common, particularly with Ginkgo biloba, lipoflavonoids, magnesium, melatonin, vitamin B12, and zinc. It is likely that some supplements will help with sleep for some patients. However, they are generally not effective, and many produced adverse effects. We concluded that dietary supplements should not be recommended to treat tinnitus but could have a positive outcome on tinnitus reactions in some people.

Evaluation of botulinum toxin A in treatment of tinnitus

OBJECTIVES: The purpose of this study was to evaluate the potential benefit of botulinum toxin A in treatment of tinnitus with a prospective, double-blinded study design.

STUDY DESIGN: Double-blinded, prospective clinical study.

METHODS: Thirty patients with tinnitus were randomly placed into 1 of 2 treatment arms. Patients either received botulinum toxin A (20 to 50 units) or saline injection at the first treatment, and the opposite treatment 4 months later. Prospective data including tinnitus matching test, tinnitus handicap inventory (THI), tinnitus rating scale (TRS), and patient questionnaires were obtained over a 4-month period after each injection.

RESULTS: Twenty-six patients completed both injections and follow-up and were included in data analysis. After botulinum toxin A, subjective tinnitus changes included 7 patients improved, 3 worsened, and 16 unchanged. Following placebo, 2 patients were improved, 7 worsened, and 17 unchanged. Comparison of the treatment and placebo groups was statistically significant (P >0.005) when including better, worse, and same effects. A significant decrease in THI scores between pretreatment and 4 month postbotulinum toxin A injection ( P = 0.0422) was recorded. None of the other comparisons of pretreatment to 1 month, or pretreatment to 4 months were significantly different.

CONCLUSIONS: This small study found improvement in THI scores and patient subjective results after botulinum toxin A injection compared with placebo, suggesting a possible benefit of botulinum toxin A in tinnitus management. Larger studies need to be completed to further evaluate potential benefits of botulinum toxin A in treatment of this difficult problem.

Is Hypozincemia Related to Tinnitus?: A Population Study Using Data From the Korea National Health and Nutrition Examination Survey

Objectives

The aim of present study was to determine the relationship between serum zinc level and tinnitus using data from the Korea National Health and Nutrition Examination Survey (KNHANES).

Methods

The present study examined the relationship between serum zinc level and tinnitus using data from the KNHANES. A total of 2,225 KNHANES participants responded to the tinnitus questionnaire and provided blood samples to measure serum zinc concentration. Based on questionnaire responses, participants were categorized into control, mild tinnitus, moderate tinnitus, and severe tinnitus subgroups.

Results

There were no significant differences between groups in serum zinc level after adjustment for sex, age, and hearing loss.

Conclusion

It was concluded that hypozincemia is not related to tinnitus in a large population.

A Systematic Review of Eligibility and Outcomes in Tinnitus Trials

Objective

To analyze existing tinnitus treatment trials with regard to eligibility criteria, outcome measures, study quality, and external validity and to recognize the effect of patient demographics, symptom duration, severity, and otologic comorbidity on research findings to help practitioners apply them to patient encounters.

Data Sources

Systematic literature search conducted by an information specialist for development of the American Academy of Otolaryngology—Head and Neck Surgery Foundation’s tinnitus clinical practice guideline.

Review Methods

Articles were assessed for eligibility with the PRISMA protocol (Preferred Reporting Items for Systematic Reviews and Meta-analyses) and data extracted by 2 independent investigators. Studies were assessed for methodological quality, inclusion and exclusion criteria, patient demographics, and outcome measures.

Results

A total of 147 randomized trials met inclusion criteria. Nearly all studies took place in a specialist setting. More than 50% did not explicitly define tinnitus, and 44% used a subjective severity threshold, such as “severely disturbing.” Fifty-four percent required symptom duration of at least 6 months for study eligibility, and up to 33% excluded patients with “organic” hearing loss or otologic conditions. Mean age was 52.2 years, and median follow-up was 3 months. Only 20% had a low risk of bias.

Conclusion

Randomized trials of tinnitus interventions are most applicable to older adults with tinnitus lasting ≥6 months who are evaluated in specialty settings. High risk of bias, short follow-up, and outcome reporting raise concerns about the validity of findings and may influence how clinicians apply trial results to individual patients and establish treatment expectations, thus demonstrating the need for further quality research in this field.

Effects of serum zinc level on tinnitus

OBJECTIVE

The aim of this study was to assess zinc levels in tinnitus patients, and to evaluate the effects of zinc deficiency on tinnitus and hearing loss.

METHODS

One-hundred patients, who presented to an outpatient clinic with tinnitus between June 2009 and 2014, were included in the study. Patients were divided into three groups according to age: Group I (patients between 18 and 30years of age); Group II (patients between 31 and 60years of age); and Group III (patients between 61 and 78years of age). Following a complete ear, nose and throat examination, serum zinc levels were measured and the severity of tinnitus was quantified using the Tinnitus Severity Index Questionnaire (TSIQ). Patients were subsequently asked to provide a subjective judgment regarding the loudness of their tinnitus. The hearing status of patients was evaluated by audiometry and high-frequency audiometry. An average hearing sensitivity was calculated as the mean value of hearing thresholds between 250 and 20,000Hz. Serum zinc levels between 70 and 120μg/dl were considered normal. The severity and loudness of tinnitus, and the hearing thresholds of the normal zinc level and zinc-deficient groups, were compared.

RESULTS

Twelve of 100 (12%) patients exhibited low zinc levels. The mean age of the zinc-deficient group was 65.41±12.77years. Serum zinc levels were significantly lower in group III (p<0.01). The severity and loudness of tinnitus were greater in zinc-deficient patients (p=0.011 and p=0.015, respectively). Moreover, the mean thresholds of air conduction were significantly higher in zinc-deficient patients (p=0.000).

CONCLUSION

We observed that zinc levels decrease as age increases. In addition, there was a significant correlation between zinc level and the severity and loudness of tinnitus. Zinc deficiency was also associated with impairments in hearing thresholds.

Clinical Practice Guideline

Objective

Tinnitus is the perception of sound without an external source. More than 50 million people in the United States have reported experiencing tinnitus, resulting in an estimated prevalence of 10% to 15% in adults. Despite the high prevalence of tinnitus and its potential significant effect on quality of life, there are no evidence-based, multidisciplinary clinical practice guidelines to assist clinicians with management. The focus of this guideline is on tinnitus that is both bothersome and persistent (lasting 6 months or longer), which often negatively affects the patient’s quality of life. The target audience for the guideline is any clinician, including nonphysicians, involved in managing patients with tinnitus. The target patient population is limited to adults (18 years and older) with primary tinnitus that is persistent and bothersome.

Purpose

The purpose of this guideline is to provide evidence-based recommendations for clinicians managing patients with tinnitus. This guideline provides clinicians with a logical framework to improve patient care and mitigate the personal and social effects of persistent, bothersome tinnitus. It will discuss the evaluation of patients with tinnitus, including selection and timing of diagnostic testing and specialty referral to identify potential underlying treatable pathology. It will then focus on the evaluation and treatment of patients with persistent primary tinnitus, with recommendations to guide the evaluation and measurement of the effect of tinnitus and to determine the most appropriate interventions to improve symptoms and quality of life for tinnitus sufferers.

Action Statements

The development group made a strong recommendation that clinicians distinguish patients with bothersome tinnitus from patients with nonbothersome tinnitus. The development group made a strong recommendation against obtaining imaging studies of the head and neck in patients with tinnitus, specifically to evaluate tinnitus that does not localize to 1 ear, is nonpulsatile, and is not associated with focal neurologic abnormalities or an asymmetric hearing loss. The panel made the following recommendations: Clinicians should (a) perform a targeted history and physical examination at the initial evaluation of a patient with presumed primary tinnitus to identify conditions that if promptly identified and managed may relieve tinnitus; (b) obtain a prompt, comprehensive audiologic examination in patients with tinnitus that is unilateral, persistent (≥ 6 months), or associated with hearing difficulties; (c) distinguish patients with bothersome tinnitus of recent onset from those with persistent symptoms (≥ 6 months) to prioritize intervention and facilitate discussions about natural history and follow-up care; (d) educate patients with persistent, bothersome tinnitus about management strategies; (e) recommend a hearing aid evaluation for patients who have persistent, bothersome tinnitus associated with documented hearing loss; and (f) recommend cognitive behavioral therapy to patients with persistent, bothersome tinnitus. The panel recommended against (a) antidepressants, anticonvulsants, anxiolytics, or intratympanic medications for the routine treatment of patients with persistent, bothersome tinnitus; (b) Ginkgo biloba, melatonin, zinc, or other dietary supplements for treating patients with persistent, bothersome tinnitus; and (c) transcranial magnetic stimulation for the routine treatment of patients with persistent, bothersome tinnitus. The development group provided the following options: Clinicians may (a) obtain an initial comprehensive audiologic examination in patients who present with tinnitus (regardless of laterality, duration, or perceived hearing status); and (b) recommend sound therapy to patients with persistent, bothersome tinnitus. The development group provided no recommendation regarding the effect of acupuncture in patients with persistent, bothersome tinnitus.

The evaluation of ozone and betahistine in the treatment of tinnitus

The aim of the study is to evaluate the effectiveness of ozone and betahistine treatments in the treatment of tinnitus. Sixty-eight patients were enrolled in this randomized, prospective controlled study. The ozone group consisted of 27, betahistine group consisted of 26 and control group consisted of 15 patients. The patients in ozone group received 10 sessions of ozone treatment via major autohemotherapy. Betahistine group received 48 mg/day betahistine tablets per oral for 3 months duration. The control group was followed up without any treatment given. The evaluation of tinnitus was made by tinnitus loudness and tinnitus handicap inventory (THI). The changes in findings from baseline to 3rd and 6th months were assessed, and the group results were compared. Comparison of the initial mean tinnitus loudness and 3 and 6 months after treatment in each of the three groups did not reveal a significant difference. The comparison between the groups in terms of the improvement of tinnitus loudness was not significant (p = 0.821). Comparison of the initial mean THI and 3 and 6 months after treatment revealed a significant difference in ozone and betahistine groups but not in the control group. When the delta (Δ) THI (the change of mean THI between the initial and 6th month) was compared between the groups, there was no significant difference. This randomized controlled study investigating the effects of ozone in tinnitus tries to shed light to a new method of treatment in tinnitus. The findings of the study does not provide enough evidence to support ozone and betahistine as a treatment for tinnitus and further research on the subject is necessary.

PHARMACOLOGICAL TREATMENTS FOR TINNITUS: NEW AND OLD

Subjective tinnitus, the phantom ringing or buzzing sensation that occurs in the absence of sound, affects 12-14% of adults; in some cases the tinnitus is so severe or disabling that patients seek medical treatment. However, although the economic and emotional impact of tinnitus is large, there are currently no FDA-approved drugs to treat this condition. Clinical trials are now underway to evaluate the efficacy of N-methyl-d-aspartate (NMDA) and dopamine D(2) antagonists, selective serotonin reuptake inhibitors (SSRIs), γ-aminobutyric acid (GABA) agonists and zinc dietary supplements. Previous off-label clinical studies, while not definitive, suggest that patients with severe depression may experience improvement in their tinnitus after treatment with antidepressants such as nortriptyline or sertraline. A small subpopulation of patients with what has been described as "typewriter tinnitus" have been shown to gain significant relief from the anticonvulsant carbamazepine. Preliminary studies with misoprostol, a synthetic prostaglandin E1 analogue, and sulpiride, a dopamine D(2) antagonist, have shown promise. Animal behavioral studies suggest that GABA transaminase inhibitors and potassium channel modulators can suppress tinnitus. Additionally, improvements in tinnitus have also been noted in patients taking melatonin for significant sleep disturbances. Like other complex neurological disorders, one drug is unlikely to resolve tinnitus in all patients; therapies targeting specific subgroups are likely to yield the greatest success.

General review of tinnitus: prevalence, mechanisms, effects, and management

Tinnitus is an increasing health concern across all strata of the general population. Although an abundant amount of literature has addressed the many facets of tinnitus, wide-ranging differences in professional beliefs and attitudes persist concerning its clinical management. These differences are detrimental to tinnitus patients because the management they receive is based primarily on individual opinion (which can be biased) rather than on medical consensus. It is thus vitally important for the tinnitus professional community to work together to achieve consensus. To that end, this article provides a broad-based review of what is presently known about tinnitus, including prevalence, associated factors, theories of pathophysiology, psychological effects, effects on disability and handicap, workers' compensation issues, clinical assessment, and various forms of treatment. This summary of fundamental information has relevance to both clinical and research arenas.

Developmental expression of two-pore domain K+ channels, TASK-1 and TREK-1, in the rat cochlea

Developmental expression of two-pore domain potassium (2P K) channels, TASK-1 and TREK-1, was investigated in the rat cochlea at onset of hearing and after maturity using RT-PCR and immunocytochemistry. TASK-1 and TREK-1 mRNAs were detected by RT-PCR at postnatal day (P) 9-12. TASK-1 like immunoreactivity (LIR) in the P13 cochlea was observed in Deiters', pillar, Claudius' and outer sulcus cells, spiral limbus fibrocytes, and neuroglia. At P13, TREK-1-LIR was more wide-spread, and included sensory and supporting cells of the organ of Corti, spiral ganglion, stria vascularis, Reissner's membrane, inner and outer sulcus cells, connective and support tissues surrounding modiolus. By P105 the pattern of TASK-1- and TREK-1-LIR became limited to a subset of the above structures, suggesting developmental regulation. During postnatal development, TASK-1 may be important in the onset (around P11) and maturation (by P22) of endocochlear potential and hearing. The distribution of TASK-1 and TREK-1 suggest a role in K cycling and homeostasis. As TASK-1 and TREK-1 are inhibited by local anesthetics at doses used to treat tinnitus, 2P K channels may also be important in cochlear dysfunction.