Current concepts in the clinical management of patients with tinnitus

Effect of Tinnitus Retraining Therapy in Normal Hearing Individual with Subjective Tinnitus: An Observational Study

This study was done to study the effect of Tinnitus Retraining Therapy (TRT) in Bilateral Normal Hearing Individual with subjective tinnitus and to evaluate the success of simplified TRT with relation to duration of tinnitus, the patient's age and state of mind. As on date there is no definite cure available for tinnitus, so current TRT focuses on reducing the impact of tinnitus on the patient's quality of life. This study included total fifty (50) participants with bilateral normal hearing sensitivity, who had reported to the department of ENT with a complaint of tinnitus in one or both ears. All the participants are active serving military personnel and their dependents of Indian Armed Forces. All the participants had undergone basic audiological test batteries to assess the hearing acuity followed by TRT and its components (TRT counselling and sound therapy) in randomized manner. Audiological test batteries include pure tone audiometry to make sure that the participants have normal hearing acuity in both the ears and then tinnitus matching i.e. pitch and loudness match and measurement of Uncomfortable Level (UCL) followed by sound therapy and counselling. There was significant improvement reported in impact of tinnitus after completion of six (06) months of TRT schedule. Amongst the participants, 40% reported with complete relief from tinnitus, 30% reported with remarkable benefit but they can still perceive the tinnitus, 20% reported with no benefit with TRT and rest of the 10% were not able to tell whether they have got any benefit or not. Normal hearing individual with tinnitus can be benefitted with TRT accompanied with counselling and the improvement in impact of tinnitus severity that ensued over six months of TRT appear to be vigorous with significant clinical outcomes.

The effect of lidocaine iontophoresis for the treatment of tinnitus: a systematic review

PURPOSE

Tinnitus is a common symptom with multiple causes and treatment options. Previous studies have investigated the effect of lidocaine iontophoresis. The aim of this review is to systematically present the effects on tinnitus and to derive possible effects.

METHODS

In accordance to the PRISMA statement, the search and analysis were performed. An abstract in German or English and a performed intervention with lidocaine iontophoresis for the treatment of tinnitus, independent of the study design, were considered as inclusion criteria. Due to the heterogeneity of the studies, only a narrative synthesis was performed.

RESULTS

The search yielded 179 studies of which 170 were excluded. Six full-texts and three abstracts were included. In total, 957 patients were treated with lidocaine iontophoresis. The percent improvement in symptoms after lidocaine iontophoresis ranged from 4% to 62%. The qualitative assessment of the studies resulted in an overall "weak" rating for all of them.

CONCLUSIONS

Due to the heterogeneity and the limited quality of the studies found, no clear statement can be made about the efficacy. The number of those who benefited from therapy varied widely. In addition, it cannot be ruled out that the effect was merely due to electrical stimulation of the cochlea.

Objective Verification of Acute Tinnitus and Validation of Efficacy of Systemic Steroids in Rats

BACKGROUND

This study was performed to identify acute tinnitus and evaluate the efficacy of steroids for noise-induced acute tinnitus by measuring the gap-prepulse inhibition of the acoustic startle (GPIAS) value in an animal model.

METHODS

Nineteen rats (the noise group [n = 7] and the noise + dexamethasone [DEX] group [n = 12]) were exposed to narrow-band noise centered at 16 kHz from a sound generator for 4 hours. The noise + DEX group received intraperitoneal steroid administration daily for 5 days (1.5 mg/kg/day) after completing noise exposure. Auditory brainstem response and GPIAS value were measured just prior to, and 1 day after noise exposure and on days 1 and 10 days after completing steroid administration. The changes in cochlear structure were evaluated by histological analysis.

RESULTS

The threshold shift was checked 1 and 10 days after intraperitoneal steroid injection, and no differences in threshold shift were observed between the two groups in each frequency except for 32 kHz 1 day after steroid injection. The mean GPIAS value in the noise + DEX group (36.4% ± 14.1%) was significantly higher than that in the noise group (16.4% ± 18.8%) 10 days after intraperitoneal steroid administration (P = 0.017). There were no pathological changes associated with noise trauma in the two groups as determined on hematoxylin and eosin and immunohistochemical staining.

CONCLUSION

An acute tinnitus model with minimal structural changes by noise exposure was set up, and used to verify tinnitus objectively by measuring the GPIAS value. Steroid therapy for control of tinnitus was validated in this animal model.

Effect of Tinnitus Retraining Therapy vs Standard of Care on Tinnitus-Related Quality of Life: A Randomized Clinical Trial

Importance

Tinnitus retraining therapy (TRT) is an internationally recognized, but controversial, protocol of uncertain efficacy that uses tinnitus-specific educational counseling (TC) and sound therapy (ST) to reduce the patient's tinnitus-evoked negative reaction to, and awareness of, tinnitus.

Objective

To compare the efficacy of TRT and its components, ST and TC, with the standard of care (SoC) in reducing the negative effect of tinnitus on quality of life.

Design, Setting, and Participants

A randomized, placebo-controlled, multicenter phase 3 trial was conducted from August 4, 2011, to June 20, 2017, at 6 US military hospitals, the study chairs' office, and a data coordinating center, among 151 active-duty and retired military personnel and dependents with functionally adequate hearing sensitivity and moderate to severe subjective tinnitus. All analyses were based on intention to treat.

Interventions

Central randomized allocation to TRT (TC and ST with conventional sound generators), partial TRT (TC with placebo sound generators), or SoC.

Main Outcomes and Measures

The primary outcome was mean change on the Tinnitus Questionnaire (TQ), assessed longitudinally between baseline and 18 months after start of therapy. The secondary outcomes were changes in TQ subscales, Tinnitus Functional Index (TFI), and Tinnitus Handicap Inventory (THI) total and subscales, as well as a 10-point visual analog scale (VAS).

Results

Among the 151 participants in the study (44 women and 107 men; mean [SD] age, 50.6 [11.3] years), 51 were randomized to receive TRT, 51 to receive partial TRT, and 49 to receive standard of care. Longitudinal analyses showed no difference between partial TRT or TRT compared with SoC, or partial TRT compared with TRT, on TQ, TFI, or THI total scores. Comparison of changes in mean score from baseline to the 18-month visit also showed no difference between treatment groups. Significant improvement was observed at 18 months in all treatment groups on TQ scores for TRT (effect size, -1.32; 95% CI, -1.78 to -0.85), partial TRT (effect size, -1.16; 95% CI, -1.56 to -0.76), and SoC (effect size, -1.01; 95% CI, -1.41 to -0.61). Compared with baseline scores, at 18 months there were reductions in scores by 7 points or more on the TQ score for 86 of 111 participants (77.55%; 95% CI, 69.7%-85.2%), 13 points or more on the TFI for 52 of 111 participants (46.8%; 95% CI, 37.6%-56.1%), 7 points or more on the THI for 63 of 111 participants (56.8%; 95% CI, 47.5%-66.0%), and 2 points or more on the VAS for 45 of 93 participants (48.4%; 95% CI, 38.2%-58.5%).

Conclusions and Relevance

There were few differences between treatment groups. About half of participants showed clinically meaningful reductions in the effect of tinnitus.

Trial Registration

ClinicalTrials.gov identifier: NCT01177137.

Tinnitus Treatment Trends

OBJECTIVE

The American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) recently published guidelines on the treatment of tinnitus. This paper examines the possible impact of those guidelines on otologic practice.

DESIGN

A survey was sent to the members of the American Neurotology Society before and after the publication of Clinical practice guideline: tinnitus. The goals of this study were to see if the guidelines changed attitudes of otologists, confirm what treatments and explanations are being used in the field before and after the guidelines were published.

MAIN OUTCOMES

Five hundred fifty-eight surveys were sent out and there were 216 responses. Otologists generally seemed to practice in accordance with the recommendations of the guidelines even before these were published. Drugs and sound therapies were not commonly used for primary tinnitus either before or after publication of the guidelines. One treatment that otologists seemed to have confidence in that was omitted from the guidelines was surgical treatment of hearing loss.

CONCLUSION

Opinions regarding the treatment of tinnitus vary considerably. The AAO-HNS clinical practice guideline: tinnitus has not significantly altered the practices of otologists, but the guidelines provide meaningful, important information for other clinicians who deal infrequently with tinnitus.

Enhancing Rehabilitative Therapies with Vagus Nerve Stimulation

Pathological neural activity could be treated by directing specific plasticity to renormalize circuits and restore function. Rehabilitative therapies aim to promote adaptive circuit changes after neurological disease or injury, but insufficient or maladaptive plasticity often prevents a full recovery. The development of adjunctive strategies that broadly support plasticity to facilitate the benefits of rehabilitative interventions has the potential to improve treatment of a wide range of neurological disorders. Recently, stimulation of the vagus nerve in conjunction with rehabilitation has emerged as one such potential targeted plasticity therapy. Vagus nerve stimulation (VNS) drives activation of neuromodulatory nuclei that are associated with plasticity, including the cholinergic basal forebrain and the noradrenergic locus coeruleus. Repeatedly pairing brief bursts of VNS sensory or motor events drives robust, event-specific plasticity in neural circuits. Animal models of chronic tinnitus, ischemic stroke, intracerebral hemorrhage, traumatic brain injury, and post-traumatic stress disorder benefit from delivery of VNS paired with successful trials during rehabilitative training. Moreover, mounting evidence from pilot clinical trials provides an initial indication that VNS-based targeted plasticity therapies may be effective in patients with neurological diseases and injuries. Here, I provide a discussion of the current uses and potential future applications of VNS-based targeted plasticity therapies in animal models and patients, and outline challenges for clinical implementation.

Serotonergic regulation of excitability of principal cells of the dorsal cochlear nucleus

The dorsal cochlear nucleus (DCN) is one of the first stations within the central auditory pathway where the basic computations underlying sound localization are initiated and heightened activity in the DCN may underlie central tinnitus. The neurotransmitter serotonin (5-hydroxytryptamine; 5-HT), is associated with many distinct behavioral or cognitive states, and serotonergic fibers are concentrated in the DCN. However, it remains unclear what is the function of this dense input. Using a combination of in vitro electrophysiology and optogenetics in mouse brain slices, we found that 5-HT directly enhances the excitability of fusiform principal cells via activation of two distinct 5-HT receptor subfamilies, 5-HT2A/2CR (5-HT2A/2C receptor) and 5-HT7R (5-HT7 receptor). This excitatory effect results from an augmentation of hyperpolarization-activated cyclic nucleotide-gated channels (Ih or HCN channels). The serotonergic regulation of excitability is G-protein-dependent and involves cAMP and Src kinase signaling pathways. Moreover, optogenetic activation of serotonergic axon terminals increased excitability of fusiform cells. Our findings reveal that 5-HT exerts a potent influence on fusiform cells by altering their intrinsic properties, which may enhance the sensitivity of the DCN to sensory input.

The Tinnitus Retraining Therapy Trial (TRTT): study protocol for a randomized controlled trial

Background

Subjective tinnitus is the perception of sound in the absence of a corresponding external sound for which there is no known medical etiology. For a minority of individuals with tinnitus, the condition impacts their ability to lead a normal lifestyle and is severely debilitating. There is no known cure for tinnitus, so current therapy focuses on reducing the effect of tinnitus on the patient’s quality of life. Tinnitus retraining therapy (TRT) uses nonpsychiatric tinnitus-specific educational counseling and sound therapy in a habituation-based protocol to reduce the patient’s tinnitus-evoked negative reaction to, and awareness of, the tinnitus, with the ultimate goal of reducing the tinnitus impact on the patient’s quality of life. Some studies support the efficacy of TRT, but no trial to date has compared TRT with the current standard of care or evaluated the separate contributions of TRT counseling and sound therapy. The Tinnitus Retraining Therapy Trial (TRTT) is a randomized, double-blind, placebo-controlled, multicenter trial for individuals with intolerable tinnitus.

Methods/design

The TRTT is enrolling active-duty and retired military personnel and their dependents with functionally adequate hearing sensitivity and severe tinnitus at US Air Force, Navy, and Army medical centers. Eligible study participants are randomized to TRT, partial TRT, or standard care to determine the efficacy of TRT and its components (TRT counseling and sound therapy). The primary outcome is change in score on the Tinnitus Questionnaire assessed longitudinally between baseline and follow-up (3, 6, 12, and 18 months following treatment). Secondary outcomes include subscale score changes in the Tinnitus Questionnaire, overall and subscale score changes in the Tinnitus Functional Index and Tinnitus Handicap Inventory, and change in the visual analog scale of the TRT Interview Form. Audiological outcomes include tinnitus pitch and loudness match and measures of loudness discomfort levels. The incidence of depression as a safety measure is assessed at each visit using the Beck Depression Inventory Fast Screen.

Trial registration

Clinicaltrials.gov NCT01177137.

Medium-level laser in chronic tinnitus treatment

The purpose of this study was to evaluate the effect of medium-level laser therapy in chronic tinnitus treatment. In a prospective double-blind placebo-controlled trial, either active laser (450 mW, 830 nm combined Ga-Al-As diode laser) or placebo irradiation was applied through the external acoustic meatus of the affected ear towards the cochlea. Fourty-eight patients with chronic tinnitus were studied. The main outcome was measured using the Goebel tinnitus questionnaire, visual analogue scales measuring the perceived loudness of tinnitus, the annoyance associated with tinnitus, and the degree of attention paid to tinnitus as well as psycho-acoustical matches of tinnitus pitch and loudness. The results did show only very moderate temporary improvement of tinnitus. Moreover, no statistically relevant differences between laser and placebo group could be found. We conclude that medium-level laser therapy cannot be regarded as an effective treatment of chronic tinnitus in our therapy regime considering the limited number of patients included in our study.

Rationale for the tinnitus retraining therapy trial

The Tinnitus Retraining Therapy Trial (TRTT) is a National Institutes of Health-sponsored, multi-centered, placebo-controlled, randomized trial evaluating the efficacy of tinnitus retraining therapy (TRT) and its component parts, directive counseling and sound therapy, as treatments for subjective debilitating tinnitus in the military. The TRTT will enroll 228 individuals at an allocation ratio of 1:1:1 to: (1) directive counseling and sound therapy using conventional sound generators; (2) directive counseling and placebo sound generators; or (3) standard of care as administered in the military. Study centers include a Study Chair's Office, a Data Coordinating Center, and six Military Clinical Centers with treatment and data collection standardized across all clinics. The primary outcome is change in Tinnitus Questionnaire (TQ) score assessed longitudinally at 3, 6, 12, and 18-month follow-up visits. Secondary outcomes include: Change in TQ sub-scales, Tinnitus Handicap Inventory, Tinnitus Functional Index, and TRT interview visual analog scale; audiometric and psychoacoustic measures; and change in quality of life. The TRTT will evaluate TRT efficacy by comparing TRT (directive counseling and conventional sound generators) with standard of care; directive counseling by comparing directive counseling plus placebo sound generators versus standard of care; and sound therapy by comparing conventional versus placebo sound generators. We hypothesize that full TRT will be more efficacious than standard of care, directive counseling and placebo sound generators more efficacious than standard of care, and conventional more efficacious than placebo sound generators in habituating the tinnitus awareness, annoyance, and impact on the study participant's life.

Targeting plasticity with vagus nerve stimulation to treat neurological disease

Pathological neural activity in a variety of neurological disorders could be treated by directing plasticity to specifically renormalize aberrant neural circuits, thereby restoring normal function. Brief bursts of acetylcholine and norepinephrine can enhance the neural plasticity associated with coincident events. Vagus nerve stimulation (VNS) represents a safe and effective means to trigger the release of these neuromodulators with a high degree of temporal control. VNS-event pairing can generate highly specific and long-lasting plasticity in sensory and motor cortex. Based on the capacity to drive specific changes in neural circuitry, VNS paired with experience has been successful in effectively ameliorating animal models of chronic tinnitus, stroke, and posttraumatic stress disorder. Targeted plasticity therapy utilizing VNS is currently being translated to humans to treat chronic tinnitus and improve motor recovery after stroke. This chapter will discuss the current progress of VNS paired with experience to drive specific plasticity to treat these neurological disorders and will evaluate additional future applications of targeted plasticity therapy.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus

BACKGROUND

This is an update of a Cochrane Review first published in The Cochrane Library in Issue 1, 2005 and previously updated in 2007 and 2009.Idiopathic sudden sensorineural hearing loss (ISSHL) is common and has a significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and result in an improvement in hearing.

OBJECTIVES

To assess the benefits and harms of HBOT for treating ISSHL and/or tinnitus.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; Database of Randomised Trials in Hyperbaric Medicine (DORCTHIM); CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 2 May 2012, following previous searches in 2009, 2007 and 2004.

SELECTION CRITERIA

Randomised studies comparing the effect on ISSHL and tinnitus of HBOT and alternative therapies.

DATA COLLECTION AND ANALYSIS

Three authors evaluated the quality of trials using the 'Risk of bias' tool and extracted data from the included trials.

MAIN RESULTS

Seven trials contributed to this review (392 participants). The studies were small and of generally poor quality. Pooled data from two trials did not show any significant improvement in the chance of a 50% increase in hearing threshold on pure-tone average with HBOT (risk ratio (RR) with HBOT 1.53, 95% confidence interval (CI) 0.85 to 2.78, P = 0.16), but did show a significantly increased chance of a 25% increase in pure-tone average (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). There was a 22% greater chance of improvement with HBOT, and the number needed to treat (NNT) to achieve one extra good outcome was 5 (95% CI 3 to 20). There was also an absolute improvement in average pure-tone audiometric threshold following HBOT (mean difference (MD) 15.6 dB greater with HBOT, 95% CI 1.5 to 29.8, P = 0.03). The significance of any improvement in tinnitus could not be assessed.There were no significant improvements in hearing or tinnitus reported for chronic presentation (six months) of ISSHL and/or tinnitus.

AUTHORS' CONCLUSIONS

For people with acute ISSHL, the application of HBOT significantly improved hearing, but the clinical significance remains unclear. We could not assess the effect of HBOT on tinnitus by pooled analysis. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously. An appropriately powered trial is justified to define those patients (if any) who can be expected to derive most benefit from HBOT.There is no evidence of a beneficial effect of HBOT on chronic ISSHL or tinnitus and we do not recommend the use of HBOT for this purpose.

Antidepressants for patients with tinnitus

BACKGROUND

This is an update of a Cochrane review first published in The Cochrane Library in Issue 4, 2006 and previously updated in 2009.Tinnitus is described as the perception of sound or noise in the absence of real acoustic stimulation. It has been compared with chronic pain, and may be associated with depression or depressive symptoms which can affect quality of life and the ability to work. Antidepressant drugs have been used to treat tinnitus in patients with and without depressive symptoms.

OBJECTIVES

To assess the effectiveness of antidepressants in the treatment of tinnitus and to ascertain whether any benefit is due to a direct tinnitus effect or a secondary effect due to treatment of concomitant depressive states.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; PsycINFO; CINAHL; Web of Science; BIOSIS; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 5 January 2012.

SELECTION CRITERIA

Randomised controlled clinical studies of antidepressant drugs versus placebo in patients with tinnitus.

DATA COLLECTION AND ANALYSIS

Two authors critically appraised the retrieved studies and extracted data independently. Where necessary we contacted study authors for further information.

MAIN RESULTS

Six trials involving 610 patients were included. Trial quality was generally low. Four of the trials looked at the effect of tricyclic antidepressants on tinnitus, investigating 405 patients. One trial investigated the effect of a selective serotonin reuptake inhibitor (SSRI) in a group of 120 patients. One study investigated trazodone, an atypical antidepressant, versus placebo. Only the trial using the SSRI drug reached the highest quality standard. None of the other included trials met the highest quality standard, due to use of inadequate outcome measures, large drop-out rates or failure to separate the effects on tinnitus from the effects on symptoms of anxiety and depression. All the trials assessing tricyclic antidepressants suggested that there was a slight improvement in tinnitus but these effects may have been attributable to methodological bias. The trial that investigated the SSRI drug found no overall improvement in any of the validated outcome measures that were used in the study although there was possible benefit for a subgroup that received higher doses of the drug. This observation merits further investigation. In the trial investigating trazodone, the results showed an improvement in tinnitus intensity and in quality of life after treatment, but in neither case reached statistical significance. Reports of side effects including sedation, sexual dysfunction and dry mouth were common.

AUTHORS' CONCLUSIONS

There is as yet insufficient evidence to say that antidepressant drug therapy improves tinnitus.

Long-term effect of acupuncture for treatment of tinnitus: a randomized, patient- and assessor-blind, sham-acupuncture-controlled, pilot trial

OBJECTIVE

The aim of this study was to investigate the long-term effect of acupuncture for treatment of tinnitus.

STUDY DESIGN

This study is a randomized, patient- and assessor-blind, sham-acupuncture-controlled, pilot trial.

SUBJECTS

Participants were adults (18-60 years old) with chronic (≥6 months), unilateral tinnitus, and without moderate or severe hearing loss.

INTERVENTIONS

Thirty-three (33) participants were randomized to one of two treatment groups: real acupuncture and sham-acupuncture (nonmeridian; no specific response, de qi). Participants received 10 sessions of acupuncture treatment (twice a week for 5 weeks), and usual patient care education.

OUTCOME MEASURES

The subjective outcome was the score of Tinnitus Handicap Inventory (THI) and Visual Analogue Scale (VAS) from baseline to 3 months after. Pure Tone Average (PTA) and Speech Discrimination (SD) from baseline to 3 months after were assessed as objective outcomes.

RESULTS

A significant interaction between time and group in VAS (p=0.017) was evident, but not in THI, PTA, and SD scores. THI showed significant improvement at the end of treatment and 3 months after, compared to baseline, in real acupuncture (p=0.004). In SD, a significant long-term effect of real acupuncture was observed until 3 months after (p=0.011). However, the effect of real acupuncture in PTA was not maintained until 3 months after the end of treatment. No significant difference in the sham-acupuncture treatment group was evident. No statistical difference in any outcome was observed between real and sham acupuncture. Only in the mean percent change of VAS, real acupuncture showed statistical significance, compared with sham-acupuncture from baseline to 3 months after (p=0.019).

CONCLUSIONS

Through evaluation of subjective (THI and VAS) and objective outcomes (PTA and SD), this study demonstrates the long-term effect of real acupuncture.

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.

Cannabinoid receptor down-regulation in the ventral cochlear nucleus in a salicylate model of tinnitus

Cannabinoid CB1 receptors have not been systematically investigated in the brainstem cochlear nucleus, nor have they been investigated in relation to tinnitus. Using immunohistochemistry and cell counting, we showed that a large number of neurons in the rat cochlear nucleus possess cannabinoid CB1 receptors. Following salicylate injections that induced the behavioural manifestations of tinnitus, the number of principal neurons in the ventral cochlear nucleus expressing CB1 receptors significantly decreased, while the number of CB1-positive principal neurons in the dorsal cochlear nucleus did not change significantly. These results suggest that CB1 receptors in the cochlear nucleus may be important for auditory function and that a down-regulation of CB1 receptors in the ventral cochlear nucleus may be related to the development of tinnitus.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSHL) with or without tinnitus is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and, it is postulated, may result in an improvement in hearing and/or a reduction in the intensity of tinnitus.

OBJECTIVES

To assess the benefits and harms of HBOT for treating ISSHL and/or tinnitus.

SEARCH STRATEGY

We initially searched in June 2004 and repeated the search in June 2006. Our search included the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 2 2006), MEDLINE (1951 to 2006), EMBASE (1974 to 2006), CINAHL, Database of Randomised Trials in Hyperbaric Medicine (DORCTHIM), AMED, LILACS, KOREAMED, INDMED, National Research Register (NRR), CSA, ISI PROCEEDINGS and ZETOC.

SELECTION CRITERIA

Randomised studies comparing the effect on ISSHL and/or tinnitus of therapeutic regimens which include HBOT with those that exclude HBOT.

DATA COLLECTION AND ANALYSIS

Three authors independently evaluated the quality of the relevant trials using the validated Oxford-Scale (Jadad 1996) and extracted the data from the included trials.

MAIN RESULTS

Six trials contributed to this review (308 subjects). Pooled data from two trials involving 114 patients did not show any significant improvement in the chance of a 50% increase in hearing threshold on Pure Tone Average (PTA) when HBOT was used (relative risk [RR] with HBOT 1.53, 95% CI 0.85 to 2.78, P = 0.16), but did show a significantly increased chance of a 25% increase in PTA (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). There was a 22% greater chance of improvement with HBOT, and the number needed to treat (NNT) to achieve one extra good outcome was five (95% CI 3 to 20). A single trial involving 50 subjects also suggested significantly more improvement in the mean PTA threshold with HBOT, expressed as a percentage of baseline (WMD 37%, 95% CI 22% to 53%, P < 0.001). The significance of any improvement following HBOT in a subjective rating of tinnitus could not be assessed due to poor reporting. There were no significant improvements in hearing or tinnitus reported in the single study to examine chronic presentation (six months) of ISSHL and/or tinnitus.

AUTHORS' CONCLUSIONS

For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear. We could not assess the effect of HBOT on tinnitus by pooled data analysis. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. There is no evidence of a beneficial effect of HBOT on chronic presentation of ISSHL and/or tinnitus and we do not recommend use of HBOT for this purpose based on the single study available.

Neuronal nitric oxide synthase expression in the cochlear nucleus in a salicylate model of tinnitus

Although a number of studies suggest that the development of tinnitus is associated with hyperactive neuronal discharges in the brainstem cochlear nucleus (CN), there is relatively little evidence to indicate the neurochemical basis of this phenomenon. While some studies suggest that it may be partly due to a decrease in GABAergic inhibition, it is also possible that increased excitability is a contributing factor. In the current study, we investigated whether the salicylate animal model of tinnitus is associated with changes in the number of CN neurons expressing neuronal nitric oxide synthase (nNOS), one of the NOS isoforms that results in the production of the neurotransmitter, nitric oxide. We used a behavioral conditioning paradigm to confirm that animals receiving salicylate injections experienced tinnitus, and used immunohistochemistry with stereology to quantify the number of nNOS-expressing neurons in the dorsal and ventral CN (DCN and VCN, respectively) in salicylate- and vehicle control-treated animals. We also employed Western blotting to quantify the amount of nNOS protein expression in the total CN (i.e., the DCN and VCN together). We found a significant increase (of approximately 70%) in the number of nNOS-expressing principal neurons in the VCN of salicylate-treated animals compared to controls, with no significant differences in the DCN; nor did we find any significant difference in the overall level of nNOS protein in the total CN using Western blotting. These results suggest that changes in the number of neurons in the VCN expressing nNOS may be implicated in the mechanisms of tinnitus.

Antidepressants for patients with tinnitus

BACKGROUND

Tinnitus is described as the perception of sound or noise in the absence of real acoustic stimulation. It has been compared with chronic pain, and may be associated with depression or depressive symptoms which can affect quality of life and the ability to work. Antidepressant drugs have been used to treat tinnitus in patients with and without depressive symptoms.

OBJECTIVES

To assess the effectiveness of antidepressants in the treatment of tinnitus and to ascertain whether any benefit was due to a direct tinnitus effect or a secondary effect due to treatment of concomitant depressive states.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) The Cochrane Library Issue 1, 2006); MEDLINE (January 1951 to 2006); EMBASE (1974 to 2006), CINAHL (to 2006), PSYCINFO (to 2006), LILACS (to 2006), and Cambridge Scientific Abstracts. The date of the most recent search was March 2006.

SELECTION CRITERIA

Randomised controlled clinical studies of antidepressant drugs versus placebo in patients with tinnitus.

DATA COLLECTION AND ANALYSIS

The studies retrieved were critically appraised and data extracted independently by two authors. Where necessary study authors were contacted for further information.

MAIN RESULTS

Five trials involving 525 patients were included. Four of these trials looked at the effect of tricyclic antidepressants on tinnitus, investigating 405 patients. One trial investigated the effect of a selective serotonin reuptake inhibitor (SSRI) in a group of 120 patients. No trials involving other antidepressant agents met the inclusion criteria. Only the trial using the SSRI drug met the highest quality standard. None of the other included trials met the highest quality standard, due to use of inadequate outcome measures, large drop out rates or failure to separate the effects on tinnitus from the effects on symptoms of anxiety and depression. All the trials assessing tricyclic antidepressants suggested that there was a slight improvement in tinnitus but these effects may have been attributable to methodological bias. The trial that investigated the SSRI drug found no overall improvement in any of the validated outcome measures that were used in the study although there was possible benefit for a subgroup that received higher doses of the drug. This observation merits further investigation. Reports of side effects including sedation, sexual dysfunction and dry mouth were common.

AUTHORS' CONCLUSIONS

There is insufficient evidence to say that antidepressant drug therapy improves tinnitus.

Randomized placebo-controlled trial of a selective serotonin reuptake inhibitor in the treatment of nondepressed tinnitus subjects

OBJECTIVE

To assess the efficacy of a selective serotonin reuptake inhibitor (paroxetine) for relief of tinnitus.

DESIGN

One hundred twenty tinnitus sufferers participated in a randomized double-blind placebo-controlled trial. Paroxetine or placebo was increased to a maximally tolerated dose (up to 50 mg/day), and patients were treated for a total of 31 days at the maximal dose.

METHODS

Patients with chronic tinnitus were recruited from our university-based specialty clinic by referral from otolaryngologists and audiologists in the local community and by advertisement. Patients with psychotic or substance use disorders or suicidal ideation were excluded, as were those using psychoactive medications (this resulted in only 1 subject with major depression in the study) or any other medications that interact with paroxetine and those with inability to hear at one's tinnitus sensation level. Fifty-eight percent of patients were male, 92% were Caucasian, and the average age was 57.

OUTCOMES MEASURES

Tinnitus matching, the Tinnitus Handicap Questionnaire, the question: How severe (bothered, aggravating) is your tinnitus? Quality of Well-Being and other psychological questionnaires.

RESULTS

Paroxetine was not statistically superior to placebo on the following tinnitus measures (tinnitus matching, 5- or 10-db drop, Tinnitus Handicap Questionnaire, quality of well-being measures, how severe, how bothered, positive change). There was a significant improvement in the single item question, How aggravating is your tinnitus? for those in the paroxetine group compared with the placebo group.

CONCLUSIONS

These results suggest that the majority of individuals in this study did not benefit from paroxetine in a consistent fashion. Further work remains to be done to determine if subgroups of patients (e.g., those who tolerate higher doses, those who are depressed) may benefit.

Hyperbaric oxygen for idiopathic sudden sensorineural hearing loss and tinnitus

BACKGROUND

Idiopathic sudden sensorineural hearing loss (ISSHL) with or without tinnitus is common and presents a health problem with significant effect on quality of life. Hyperbaric oxygen therapy (HBOT) may improve oxygen supply to the inner ear and thereby result in an improvement in hearing and/or a reduction in the intensity of tinnitus.

OBJECTIVES

To assess the benefits and harms of HBOT for treating ISSHL and tinnitus.

SEARCH STRATEGY

We searched the Cochrane ENT Specialist Register (June 2004), CENTRAL (The Cochrane Library Issue 3, 2004), MEDLINE (1966 to 2004), EMBASE (1974 to 2004), CINAHL (1982 to 2004), DORCTHIM (1996 to 2004), and reference lists of articles. Researchers in the field were contacted.

SELECTION CRITERIA

Randomised studies comparing the effect on ISSHL and/or tinnitus of therapeutic regimens which include HBOT with those that exclude HBOT.

DATA COLLECTION AND ANALYSIS

Three reviewers independently evaluated the quality of the relevant trials using the validated Jadad 1996 Oxford-Scale and extracted the data from the included trials.

MAIN RESULTS

Five trials contributed to this review (254 subjects, 133 receiving HBOT and 120 control). Pooled data from two trials involving 114 patients (45% of the total) suggested there was a trend towards, but no significant increase in, the chance of a 50% increase in hearing threshold on Pure Tone Average (PTA) over four frequencies when HBOT was used (relative risk (RR) for good outcome with HBOT 1.53, 95% confidence interval (CI) 0.85 to 2.78, P = 0.16). The chance of achieving a 25% increase with HBOT was, however, statistically significant (RR 1.39, 95% CI 1.05 to 1.84, P = 0.02). Fifty-six per cent of the control subjects achieved this outcome versus 78% of the HBOT subjects, with the number-needed-to-treat (NNT) to achieve one extra good outcome being 5 (95% CI 3 to 20). A single trial involving 50 subjects (20% of the total) also suggested a significant improvement in the mean PTA threshold expressed as a percentage of baseline (61% improvement with HBOT, 24% with control, WMD 37%, 95% CI 22% to 53%). The effect of HBOT in tinnitus could not be assessed due to poor reporting. There were no significant improvements in hearing or tinnitus reported in the single study to examine the effect of HBOT on a chronic presentation (six months) of ISSHL and/or tinnitus.

AUTHORS' CONCLUSIONS

For people with early presentation of ISSHL, the application of HBOT significantly improved hearing loss, but the clinical significance of the level of improvement is not clear. We could not assess the effect of HBOT on tinnitus by pooled analysis. The routine application of HBOT to these patients cannot be justified from this review. In view of the modest number of patients, methodological shortcomings and poor reporting, this result should be interpreted cautiously, and an appropriately powered trial of high methodological rigour is justified to define those patients (if any) who can be expected to derive most benefit from HBOT. There is no evidence of a beneficial effect of HBOT on chronic presentation of ISSHL and/or tinnitus.

The role of zinc in the treatment of tinnitus

OBJECTIVE

This study was designed to investigate the role of zinc administration in treatment of tinnitus.

STUDY DESIGN

Randomized, prospective, placebo-controlled study.

SETTING

Patients with tinnitus were admitted to the ear, nose, and throat clinic of the authors' hospital.

PATIENTS

Patients with tinnitus with no know pathologic conditions of the ear, nose, and throat; the mean age of 28 patients receiving zinc was 51.2 years, and that of 13 patients given placebo was 55 years.

INTERVENTION

Blood zinc levels were measured. Frequency was detected by audiometry, and loudness of tinnitus was screened by tinnitus match test. A questionnaire that scored tinnitus subjectively between 0 and 7 was given to patients before zinc treatment. After 2 months of treatment (zinc 50 mg daily to zinc group, placebo pill containing starch to placebo group), all of the tests were performed again. There was no difference in age, sex, duration of tinnitus, and affected ears between the patients treated with zinc and those treated with placebo. Blood zinc levels were lower than normal in 31% of patients before treatment.

MAIN OUTCOME MEASURES

A decrease in tinnitus loudness by at least 10 dB was accepted as clinically favorable progress. A decrease of more than 1 point in subjective tinnitus scoring was accepted as valid.

RESULTS

Clinically favorable progress was detected in 46.4% of patients given zinc. Although this decrease was not statistically significant, the severity of subjective tinnitus decreased in 82% of the patients receiving zinc. The mean of subjective tinnitus decreased from 5.25 +/- 1.08 to 2.82 +/- 1.81 ( < 0.001). However, the decrease in severity of the tinnitus was not significant in patients receiving placebo.

CONCLUSION

It can be concluded that patients with tinnitus may have low blood zinc levels (31%) and clinical and subjective improvement can be achieved by oral zinc medication. However, it remains to be seen whether the longer duration of treatment has more significant results.

The low-power laser in the treatment of tinnitus

The purpose of this study was to evaluate the low-power laser on the treatment of tinnitus. In a randomized, prospective, double-blind, placebo-controlled trial, either active or placebo low-power laser irradiation was given through the external acoustic meatus of the affected ear towards the cochlea. The active laser applied 50 mW (cw, 830 nm) over a period of 10 min per session. Forty-nine patients with severe, chronic uni- or bilateral tinnitus were studied. The main outcome was measured using psychoacoustical match of tinnitus loudness and pitch, Visual Analogue Scale (VAS) ratings of subjective loudness, annoyance and attention involved, scores on the Tinnitus Handicap Inventory (THI), the Tinnitus Coping Style Questionnaire (TCSQ), and a number of psychosocial questionnaires. The results showed only moderate (18%) subjective improvement with no statistically significant differences between the effects of the active laser and placebo treatments. Also, there were no statistically significant differences in prepost measurements of tinnitus loudness, VAS scores, THI scores, or TCSQ scores for patients treated with active laser compared with those treated with placebo. We conclude that low-power laser treatment is not indicated in the treatment of tinnitus. Reports of significant benefits of this treatment in previous, mostly uncontrolled or single-blinded studies may be explained by the placebo effect.

Recent advances in the pharmacological treatment of tinnitus

Tinnitus is an extremely prevalent condition that impinges on the lives of sufferers to varying degrees. In some people, it is a fairly minor irritation but, for many, the tinnitus intrudes to such a degree that it affects their ability to lead a normal life, and in some very extreme cases has resulted in suicide. Insomnia, inability to concentrate and depression are commonly reported to accompany the condition. Relief can be reliably obtained using intravenous lignocaine, which indicates that pharmacology can provide a route for effective alleviation of the condition. In this article, Julie Simpson and Ewart Davies review the potential pharmacological therapies, and emphasize that clinical research has been hampered by the absence of a reliable objective assessment of the tinnitus and by the variable nature of the complaint.