Clonazepam quiets tinnitus: a randomised crossover study with Ginkgo biloba

Easing the Burden of Tinnitus: A Narrative Review for Exploring Effective Pharmacological Strategies

Many individuals seek medical attention for tinnitus, desiring relief from the distress caused by the condition; however, the treatment process is far from straightforward. The most effective treatments for chronic subjective tinnitus, such as tinnitus retraining therapy (TRT) and cognitive behavioral therapy (CBT), require considerable time and efforts. As a result, many of them express a desire for alleviation through medication. While it is true that medication is not generally recommended in treatment guidelines for chronic subjective tinnitus, in specific situations such as when accompanied by symptoms of depression or anxiety-drugs like antidepressants or anxiolytics may have a meaningful impact on symptom reduction. Additionally, medication can prove effective in certain specialized forms of tinnitus, such as typewriter tinnitus, as opposed to chronic subjective tinnitus. Although intratympanic dexamethasone injections for tinnitus have been reported to lack efficacy compared to a placebo, if patients perceive subjective satisfaction due to a placebo effect, it holds significance. From the perspective of patients suffering from tinnitus, even if the therapeutic mechanism is set aside, experiencing some degree of relief through certain medications can enhance compliance with evidence-based treatments like TRT and CBT.

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

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

The Effect of Anxiolytics on Tinnitus

Tinnitus is a perceptual disorder in which sound is perceived by the patient in the absence of an external or internal acoustic stimulation [...].

Current and Emerging Therapies for Chronic Subjective Tinnitus

IMPORTANCE

Chronic subjective tinnitus, the perception of sound without an external source for longer than six months, may be a greatly debilitating condition for some people, and is associated with psychiatric comorbidities and high healthcare costs. Current treatments are not beneficial for all patients and there is a large need for new therapies for tinnitus.

OBSERVATIONS

Unlike rarer cases of objective tinnitus, chronic subjective tinnitus often has no obvious etiology and a diverse pathophysiology. In the absence of objective testing, diagnosis is heavily based on clinical assessment. Management strategies include hearing aids, sound masking, tinnitus retraining therapy, cognitive behavioral therapy, and emerging therapies including transcranial magnetic stimulation and electrical stimulation.

CONCLUSIONS AND RELEVANCE

Although current treatments are limited, emerging diagnostics and treatments provide promising avenues for the management of tinnitus symptoms.

Herbal medicines in the treatment of tinnitus: An updated review

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

Geriatrics on beers criteria medications at risk of adverse drug events using real-world data

OBJECTIVES

The established Beers Criteria consider side effects and safety concerns when prescribing drugs to the elderly. As the criteria suggest that attention should be paid toward prescriptions rather than prescription prohibition lists, these Beers Criteria medications (BCMs) are used appropriately under unavoidable circumstances.

METHODS

Patients aged ≥ 65 years and with an experience of being prescribed inappropriate medications at Konyang University Hospital, South Korea, were selected. We analyzed data from the Korea Adverse Event Reporting System (KAERS) and the Food and Drug Administration Adverse Event Reporting System (FAERS) of the United States to identify medication-induced adverse drug events (ADEs). The actual incidence was predicted by multiplying the incidence and number of BCMs prescribed to the patients. The proportional reporting ratio (PRR) and reporting odds ratio (ROR) were calculated using KAERS and FAERS data.

RESULTS

We predicted that the incidence of ADEs would be higher for metoclopramide, chlorpheniramine, and amitriptyline in patients using medications for more than 1 day and metoclopramide, chlorpheniramine, and ketoprofen in patients using medications only for 1 day. Among the ADEs reported to KAERS and FAERS, significant ROR and PRR values were noted for clonazepam (drowsiness), nortriptyline (sleepiness), and zolpidem (amnesia, somnambulism, agitation, dependence, nightmare, and dysgeusia).

CONCLUSION

This study highlighted the actual status of BCM prescriptions in clinical institutions and predicted the incidence of ADEs. We concluded that greater care must be taken while prescribing BCMs to the elderly and indicators, such as PRR and ROR should be monitored regularly.

Review of Pharmacotherapy for Tinnitus

Various medications are currently used in the treatment of tinnitus, including anesthetics, antiarrhythmics, anticonvulsants, antidepressants, antihistamines, antipsychotics, anxiolytics, calcium channel blockers, cholinergic antagonists, NMDA antagonists, muscle relaxants, vasodilators, and vitamins. To date, however, no medications have been specifically approved to treat tinnitus by the US Food and Drug Administration (FDA). In addition, medicines used to treat other diseases, as well as foods and other ingested materials, can result in unwanted tinnitus. These include alcohol, antineoplastic chemotherapeutic agents and heavy metals, antimetabolites, antitumor agents, antibiotics, caffeine, cocaine, marijuana, nonnarcotic analgesics and antipyretics, ototoxic antibiotics and diuretics, oral contraceptives, quinine and chloroquine, and salicylates. This review, therefore, describes the medications currently used to treat tinnitus, including their mechanisms of action, therapeutic effects, dosages, and side-effects. In addition, this review describes the medications, foods, and other ingested agents that can induce unwanted tinnitus, as well as their mechanisms of action.

Investigating the efficacy of fluoxetine vs. fluoxetine plus alprazolam (single therapy vs. combination therapy) in treatment of chronic tinnitus: A placebo-controlled study

OBJECTIVE

To investigate the effect of combination therapy (fluoxetine + alprazolam) and fluoxetine alone in treatment of tinnitus.

MATERIAL AND METHODS

147 participants with chronic tinnitus were divided into three groups (fluoxetine, fluoxetine+ alprazolam, and placebo). Tinnitus Handicap Inventory (THI), Visual Analogue Scale (VAS), Tinnitus Severity Index (TSI), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI) used to assess tinnitus. Effect size according to partial Eta square calculated and level of significance was considered as P < 0.05.

RESULTS

Fluoxetine reduced VAS, THI, BDI, and increased BAI. The combination therapy significantly reduced VAS, THI, BAI, and BDI. None of them reduced the TSI. The effect size for BAI and BDI were 0.135 (medium) and 0.075 (small), respectively. There was no significant difference between combination and single-drug therapy.

CONCLUSION

Both groups improved THI and VAS. Combination therapy was not significantly different from single-drug treatment. Combination therapy can be considered only according to the psychiatric needs of patients.

Methodological Aspects of Randomized Controlled Trials for Tinnitus: A Systematic Review and How a Decision Support System Could Overcome Barriers

Although a wide range of tinnitus management interventions is currently under research and a variety of therapeutic interventions have already been applied in clinical practice, no optimal and universal tinnitus treatment has been reached yet. This fact is to some extent a consequence of the high heterogeneity of the methodologies used in tinnitus related clinical studies. In this manuscript, we have identified, summarized, and critically appraised tinnitus-related randomized clinical trials since 2010, aiming at systematically mapping the research conducted in this area. The results of our analysis of the 73 included randomized clinical trials provide important insight on the identification of limitations of previous works, methodological pitfalls or gaps in current knowledge, a prerequisite for the adequate interpretation of current literature and execution of future studies.

Clinical randomized trial study of hearing aids effectiveness in association with Ginkgo biloba extract (EGb 761) on tinnitus improvement

Introduction

Tinnitus is defined as the perception of sound without its actual presence in the environment. It has been the subject of a great number of studies, especially considering its consequences on patient's quality of life.

Objective

This study aimed to investigate the effect of hearing aids and/or Ginkgo biloba extract EGb 761 on tinnitus in patients with hearing loss.

Methods

This is a trial randomized-controlled treatment, parallel, double-blind, with three-arm. Thirty-three adults subjects were divided into three groups: group 1 — subjects undergoing drug therapy with Ginkgo biloba extract EGb 761; group 2 — individuals fitted with digital hearing aids; group 3 — individuals submitted to drug therapy with Ginkgo biloba extract EGb 761 and using hearing aids. The tinnitus handicap inventory and visual analogue scale were used to evaluate self-perception of tinnitus loudness and severity before treatment and 90 days after treatment.

Results

This study demonstrated a significant correlation between tinnitus handicap inventory and visual analogue scale, before and after treatment. We observed a significant improvement in self-perception of tinnitus loudness and severity after 90 days of treatment with Ginkgo biloba extract EGb 761 and/or hearing aids. No correlation was found between tinnitus onset time and self-perception of tinnitus loudness and severity. Hearing aids were more effective in patients with a shorter tinnitus onset time and Ginkgo biloba extract was effective regardless of tinnitus duration.

Conclusions

It was possible to prove the effectiveness of the hearing aids and/or Ginkgo biloba extract EGb 761 treatment, which shows success in the control of tinnitus contributing to the improvement of this symptom.

Auditory Neural Plasticity in Tinnitus Mechanisms and Management

Tinnitus, which is the perception of sound in the absence of a corresponding external acoustic stimulus, including change of hearing and neural plasticity, has become an increasingly important ailment affecting the daily life of a considerable proportion of the population and causing significant burdens for both the affected individuals and society as a whole. Here, we briefly review the epidemiology and classification of tinnitus, and the currently available treatments are discussed in terms of the available evidence for their mechanisms and efficacy. The conclusion drawn from the available evidence is that there is no specific medication for tinnitus treatment at present, and tinnitus management might provide better solutions. Therapeutic interventions for tinnitus should be based on a comprehensive understanding of the etiology and features of individual cases of tinnitus, and more high quality and large-scale research studies are urgently needed to develop more efficacious medications.

Tinnitus associated with benzodiazepine withdrawal syndrome: A case report and literature review

In light of the ongoing opioid crisis, many have encouraged the medical community as well as local and national US government agencies to reconsider the prevalent use of benzodiazepines. As prescribers continue to weigh the risks and benefits of ongoing benzodiazepine use, care must be taken when the decision is made to taper and discontinue these medications in patients who have been maintained on them chronically. We present a case of an adult patient maintained on a benzodiazepine for several years who developed tinnitus during a gradual dose taper. This patient developed tinnitus within 7 weeks of gradual reduction of the patient's clonazepam dose to 50% of the original dose in an outpatient clinic. The persistence of these symptoms prevented further dose reductions. Upon review of the available literature, several other cases were identified describing development of tinnitus upon discontinuation or tapering of a benzodiazepine. In weighing the risks and benefits of chronic benzodiazepine therapy, tinnitus must be considered as a rare but debilitating and long-term risk of benzodiazepine withdrawal. Providers must be prepared to individualize benzodiazepine tapers and be vigilant about emergence of withdrawal symptoms to prevent undue stress in patients.

Current Validated Medical Treatments: Pharmacologic Interventions

The search for an effective medication that will eliminate tinnitus has a long history. Currently, no drugs exist that universally cure tinnitus. Pharmacologic interventions that have been investigated can be divided into those that attempt to eliminate the perception of tinnitus, and those that are designed to treat the negative comorbidities associated with tinnitus, thereby mitigating tinnitus' negative impact on quality of life. A third category of drugs can also be considered that addresses an identified pathologic condition that has tinnitus as an associated symptom (for example, Meniere's disease, otosclerosis, migraine-associated vertigo). This third category is not addressed.

Pharmacotherapy of Tinnitus

Tinnitus is a common symptom for which there is in most cases no causal therapy. The search for an improvement of tinnitus through pharmacological interventions has a long tradition. The observation that tinnitus can be transiently suppressed by the use of lidocaine has shown that the symptom is susceptible to pharmacotherapy. So far, however, no medication has been found for either acute or chronic subjective tinnitus that reliably leads to a long-term reduction or even complete disappearance of the symptom for the majority of tinnitus sufferers. Nevertheless, in everyday clinical life, drugs are frequently used, usually off-label, to relieve tinnitus or tinnitus-associated symptoms (e.g. sleep disturbance, depression, anxiety disorder or hearing loss). This chapter shows the different approaches to acute and chronic subjective tinnitus by means of pharmacotherapeutic interventions. Furthermore, this review reports on the scientific studies carried out in this area in recent years and explains the difficulties in finding a suitable medication for most forms of tinnitus. In addition, it reports on the pharmacotherapeutic options for objective tinnitus and describes the development of tinnitus as a side effect of certain drugs. Finally, possible target structures are mentioned, which should possibly be addressed in pharmacological studies in the near future.

Tinnitus Management in Lateral Skull Base Lesions

Tinnitus, the phantom perception of sound in the absence of a physical sound source, is a complex problem with multiple etiologies. While most commonly presenting in a subjective fashion caused by measurable hearing loss, other etiologies including lateral skull base tumors that encroach on middle and inner ear structures can lead to phantom sound perception as well. In addition to discussing the basic background of tinnitus, here we also review current theories of etiology that include central auditory and nonauditory neural mechanisms and potential treatments that range from sound therapy to medications to cognitive and behavioral therapies and cranial nerve and brain stimulation. One main purpose of this article is to relate tinnitus causes to skull base tumors, surgical removal, and resultant sequelae, including damage to cranial nerves resulting in audiovestibular dysfunction. We also discuss the utility of microvascular decompression for both tumor and nontumor-associated tinnitus and the current literature regarding hearing preservation rates and tinnitus perception, where documented, with the three common treatment modalities employed for most lateral skull base tumors that includes watchful waiting with serial imaging, stereotactic radiosurgery and primary surgical resection using hearing preservation and hearing ablative approaches. The management of skull base tumors is a complex process that depending upon the approach and sequelae, may lead to manageable or worsening phantom sound perception that must be considered when discussing the multiple treatment options with patients.

Traditional oriental medicine for sensorineural hearing loss: Can ethnopharmacology contribute to potential drug discovery?

ETHNOPHARMACOLOGICAL RELEVANCE

In Traditional Oriental Medicine (TOM), the development of hearing pathologies is related to an inadequate nourishment of the ears by the kidney and other organs involved in regulation of bodily fluids and nutrients. Several herbal species have historically been prescribed for promoting the production of bodily fluids or as antiaging agents to treat deficiencies in hearing.

AIM OF REVIEW

The prevalence of hearing loss has been increasing in the last decade and is projected to grow considerably in the coming years. Recently, several herbal-derived products prescribed in TOM have demonstrated a therapeutic potential for acquired sensorineural hearing loss and tinnitus. Therefore, the aims of this review are to provide a comprehensive overview of the current known efficacy of the herbs used in TOM for preventing different forms of acquired sensorineural hearing loss and tinnitus, and associate the traditional principle with the demonstrated pharmacological mechanisms to establish a solid foundation for directing future research.

METHODS

The present review collected the literature related to herbs used in TOM or related compounds on hearing from Chinese, Korean, and Japanese herbal classics; library catalogs; and scientific databases (PubMed, Scopus, Google Scholar; and Science Direct).

RESULTS

This review shows that approximately 25 herbal species and 40 active compounds prescribed in TOM for hearing loss and tinnitus have shown in vitro or in vivo beneficial effects for acquired sensorineural hearing loss produced by noise, aging, ototoxic drugs or diabetes. The inner ear is highly vulnerable to ischemia and oxidative damage, where several TOM agents have revealed a direct effect on the auditory system by normalizing the blood supply to the cochlea and increasing the antioxidant defense in sensory hair cells. These strategies have shown a positive impact on maintaining the inner ear potential, sustaining the production of endolymph, reducing the accumulation of toxic and inflammatory substances, preventing sensory cell death and preserving sensory transmission. There are still several herbal species with demonstrated therapeutic efficacy whose mechanisms have not been deeply studied and others that have been traditionally used in hearing loss but have not been tested experimentally. In clinical studies, Ginkgo biloba, Panax ginseng, and Astragalus propinquus have demonstrated to improve hearing thresholds in patients with sensorineural hearing loss and alleviated the symptoms of tinnitus. However, some of these clinical studies have been limited by small sample sizes, lack of an adequate control group or contradictory results.

CONCLUSIONS

Current therapeutic strategies have proven that the goal of the traditional oriental medicine principle of increasing bodily fluids is a relevant approach for reducing the development of hearing loss by improving microcirculation in the blood-labyrinth barrier and increasing cochlear blood flow. The potential benefits of TOM agents expand to a multi-target approach on different auditory structures of the inner ear related to increased cochlear blood flow, antioxidant, anti-inflammatory, anti-apoptotic and neuroprotective activities. However, more research is required, given the evidence is very limited in terms of the mechanism of action at the preclinical in vivo level and the scarce number of clinical studies published.

BOLD fMRI effects of transcutaneous vagus nerve stimulation in patients with chronic tinnitus

Objective

Vagus nerve stimulation (VNS) is a neuromodulation method used for treatment of epilepsy and depression. Transcutaneous VNS (tVNS) has been gaining popularity as a noninvasive alternative to VNS. Previous tVNS neuroimaging studies revealed brain (de)activation patterns that involved multiple areas implicated in tinnitus generation and perception. In this study, functional magnetic resonance imaging (fMRI) was used to explore the effects of tVNS on brain activity in patients with tinnitus.

Methods

Thirty-six patients with chronic tinnitus received tVNS to the inner tragus, cymba conchae, and earlobe (sham stimulation).

Results

The locus coeruleus and nucleus of the solitary tract in the brainstem were activated in response to stimulation of both locations compared with the sham stimulation. The cochlear nuclei were also activated, which was not observed in healthy subjects with normal hearing. Multiple auditory and limbic structures, as well as other brain areas associated with generation and perception of tinnitus, were deactivated by tVNS, particularly the parahippocampal gyrus, which was recently speculated to cause tinnitus in hearing-impaired patients.

Conclusions

tVNS via the inner tragus or cymba conchae suppressed neural activity in the auditory, limbic, and other tinnitus-related non-auditory areas through auditory and vagal ascending pathways in tinnitus patients. The results from this study are discussed in the context of several existing models of tinnitus. They indicate that the mechanism of action of tVNS might be involved in multiple brain areas responsible for the generation of tinnitus, tinnitus-related emotional annoyance, and their mutual reinforcement.

South Korean geriatrics on Beers Criteria medications at risk of adverse drug events

Background

The Beers Criteria released by the American Geriatrics Society includes a list of drugs to avoid in the geriatric population and is frequently used as a safety resource in geriatric pharmacotherapy.

Objective

To evaluate the exposure of South Korean geriatrics to potentially inappropriate medications according to the Beers Criteria and the risk of adverse events from these medications.

Methods

This study included medications recommended to be avoided in patients 65 years or older regardless of concomitant drug therapy or disease. The exposure of South Korean geriatrics to each of the study medications were examined using health claims data of 2011. The number of South Korean geriatrics at risk of experiencing adverse drug events from the study medications were estimated by multiplying the number of patients exposed to the medication in 2011 and the incident rate of the event obtained from literature sources.

Results

This study examined 166,822 geriatrics for Beers Criteria medication exposure and adverse drug event risk. The most prevalent Beers Criteria medication prescribed in South Korean geriatrics >1 day was chlorpheniramine (53.9%) and the adverse drug event with the highest number of this geriatric population at risk of was amitriptyline related dry mouth (4.9%). The proportion of South Korean geriatrics on chronic Beers Criteria medications >1 day at risk of adverse drug events from these medications was significantly higher than in US geriatrics (0.005 vs. 0.001, 2-way ANOVA post hoc pairwise t-test P<0.0001).

Conclusions

In 2011, over half of South Korean geriatrics was exposed to medications recommended to be avoided in geriatrics and their adverse drug event risk warrants close monitoring of their occurrence.

Tinnitus and sound intolerance: evidence and experience of a Brazilian group

Introduction

Tinnitus and sound intolerance are frequent and subjective complaints that may have an impact on a patient's quality of life.

Objective

To present a review of the salient points including concepts, pathophysiology, diagnosis and approach of the patient with tinnitus and sensitivity to sounds.

Methods

Literature review with bibliographic survey in LILACS, SciELO, Pubmed and MEDLINE database. Articles and book chapters on tinnitus and sound sensitivity were selected. The several topics were discussed by a group of Brazilian professionals and the conclusions were described.

Results

The prevalence of tinnitus has increased over the years, often associated with hearing loss, metabolic factors and inadequate diet. Medical evaluation should be performed carefully to guide the request of subsidiary exams. Currently available treatments range from medications to the use of sounds with specific characteristics and meditation techniques, with variable results.

Conclusion

A review on tinnitus and auditory sensitivity was presented, allowing the reader a broad view of the approach to these patients, based on scientific evidence and national experience.

Evidence and evidence gaps in tinnitus therapy

A nearly endless number of procedures has been tried and in particular sold for the treatment of tinnitus, unfortunately they have not been evaluated appropriately in an evidence-based way. A causal therapy, omitting the tinnitus still does not exist, actually it cannot exist because of the various mechanisms of its origin. However or perhaps because of that, medical interventions appear and reappear like fashion trends that can never be proven by stable and reliable treatment success. This contribution will discuss and acknowledge all current therapeutic procedures and the existing or non-existing evidence will be assessed. Beside external evidence, the term of evidence also encompasses the internal evidence, i.e. the experience of the treating physician and the patient's needs shall be included. While there is no evidence for nearly all direct procedures that intend modulating or stimulating either the cochlea or specific cervical regions such as the auditory cortex, there are therapeutic procedures that are acknowledged in clinical practice and have achieved at least a certain degree of evidence and generate measurable effect sizes. Those are in particular habituation therapy and psychotherapeutic measures, especially if they are combined with concrete measures for improved audio perception (hearing aids, CI, hearing therapies).

The Management and Outcomes of Pharmacological Treatments for Tinnitus

Tinnitus, a phantom sensation experienced by people around the world, currently is endured without a known cure. Some find the condition tolerable, while others are tortured on a daily basis from the incessant phantom noises. For those who seek treatment, oftentimes, they have a comorbid condition (e.g., depression, anxiety, insomnia), which is treated pharmaceutically. These products aim to reduce the comorbities associated with tinnitus thereby minimizing the overall burden present. Because of the phantom nature of tinnitus, it is often compared to neurologic pain. Since pain can be managed with pharmaceutical options, it is reasonable to assume that similar agents might work to alleviate tinnitus. The effects of antidepressants, benzodiazepines, anticonvulsants, and glutamate antagonists are reviewed in this paper. Table 1 summarizes the pharmaceutical products discussed. Due to the variety of comorbid factors and potential causes of tinnitus, there may not be one pharmaceutical treatment that will combat every type of tinnitus. Nevertheless, a product that finally addresses the true cause of tinnitus, and not just its comorbidities, will benefit millions of people worldwide.

Treatment of tinnitus

PURPOSE OF REVIEW

Tinnitus, the perception of sound in the absence of a corresponding external acoustic stimulus, is a highly prevalent and frequently severely impairing disorder with worldwide impact. In this article after a short overview about epidemiology and pathophysiology the currently available treatment options will be discussed with specific consideration of the available evidence, their mechanisms of action and their limitations.

RECENT FINDINGS

During the last decades, advances in neuroimaging methods and the development of animal models have contributed to an increasing understanding of the neuronal correlates of tinnitus and have motivated the development of innovative brain-based treatment approaches for directly targeting the neuronal correlates of tinnitus. A further important development has been the insight that there exist different forms of tinnitus that differ in their pathophysiology and their response to specific treatments.

SUMMARY

Treatment of tinnitus should be based on a comprehensive diagnosis of etiologic and concomitant aspects of an individual's tinnitus. Already today a large variety of therapeutic interventions are available, which can efficiently reduce tinnitus severity. Several innovative treatment approaches are currently under development.

Parallels between phantom pain and tinnitus

Phantom pain and tinnitus are diseases that cause patients great discomfort. Both are phantom sensations that have many connections with cerebral structures, but their underlying mechanisms are not fully understood. Several therapies have been suggested for these conditions over the years, but there is still no consensus on how to treat either one. Comparison of these two phenomena reveals many similarities, including what is known about their underlying mechanisms, associated brain areas, and responses to therapeutic agents and methods. These similarities need to be evaluated in greater depth, as this could improve our understanding of tinnitus and phantom pain, and thereby improve management strategies for these conditions.

Human Auditory Cortex Neurochemistry Reflects the Presence and Severity of Tinnitus

It is not known why tinnitus occurs in some cases of hearing damage but not others. Abnormalities of excitation-inhibition balance could influence whether tinnitus develops and its severity if it does. Animal models of hearing damage, which also produce tinnitus based on behavioral evidence, have identified abnormalities of GABAergic inhibition, both cortically and subcortically. However, the precise relationships of GABA inhibitory changes to tinnitus itself, as opposed to other consequences of hearing damage, remain uncertain. Here, we used magnetic resonance spectroscopy to non-invasively quantify GABA in the left (LAC) and right (RAC) auditory cortices of a group of 14 patients with lateralized tinnitus (eight left ear) and 14 controls matched for age, sex, and hearing. We also explored the potential relationships with other brain metabolites (i.e., choline, N-acetylaspartate, and creatine). The presence of tinnitus was associated with a reduction in auditory cortex GABA concentration. Regardless of tinnitus laterality, post hoc testing indicated reductions that were significant in RAC and nonsignificant in LAC. Tinnitus severity and hearing loss were correlated positively with RAC choline but not GABA. We discuss the results in the context of current models of tinnitus and methodological constraints.

SIGNIFICANCE STATEMENT

Permanently affecting one in seven adults, tinnitus lacks both widely effective treatments and adequate understanding of its brain mechanisms. Existing animal models represent tinnitus that may not be distinguishable from homeostatic responses to the auditory insults used to induce it. Human studies can be well controlled in this regard but are usually not (with few even matching control subjects for hearing loss) and are limited in scope as a result of relying solely on non-invasive recording techniques. Here, we exploit recent advances in non-invasive spectroscopic techniques to establish, in a human study tightly controlled for hearing loss and hyperacusis, that tinnitus is associated with a significant reduction in auditory cortex GABA concentration, which has implications for understanding and treatment of the condition.

Maladaptive plasticity in tinnitus--triggers, mechanisms and treatment

Tinnitus is a phantom auditory sensation that reduces quality of life for millions of people worldwide, and for which there is no medical cure. Most cases of tinnitus are associated with hearing loss caused by ageing or noise exposure. Exposure to loud recreational sound is common among the young, and this group are at increasing risk of developing tinnitus. Head or neck injuries can also trigger the development of tinnitus, as altered somatosensory input can affect auditory pathways and lead to tinnitus or modulate its intensity. Emotional and attentional state could be involved in the development and maintenance of tinnitus via top-down mechanisms. Thus, military personnel in combat are particularly at risk owing to combined risk factors (hearing loss, somatosensory system disturbances and emotional stress). Animal model studies have identified tinnitus-associated neural changes that commence at the cochlear nucleus and extend to the auditory cortex and other brain regions. Maladaptive neural plasticity seems to underlie these changes: it results in increased spontaneous firing rates and synchrony among neurons in central auditory structures, possibly generating the phantom percept. This Review highlights the links between animal and human studies, and discusses several therapeutic approaches that have been developed to target the neuroplastic changes underlying tinnitus.

Sensorineural Tinnitus: Its Pathology and Probable Therapies

Tinnitus is not a single disease but a group of different diseases with different pathologies and therefore different treatments. Regarding tinnitus as a single disease is hampering progress in understanding of the pathophysiology of tinnitus and perhaps, more importantly, it is a serious obstacle in development of effective treatments for tinnitus. Subjective tinnitus is a phantom sound that takes many different forms and has similarities with chronic neuropathic pain. The pathology may be in the cochlea, in the auditory nerve, or, most commonly, in the brain. Like chronic neuropathic pain tinnitus is not life threatening but influences many normal functions such as sleep and the ability to concentrate on work. Some forms of chronic tinnitus have two components, a (phantom) sound and a component that may best be described as suffering or distress. The pathology of these two components may be different and the treatment that is most effective may be different for these two components. The most common form of treatment of tinnitus is pharmacological agents and behavioral treatment combined with sound therapy. Less common treatments are hypnosis and acupuncture. Various forms of neuromodulation are becoming in use in an attempt to reverse maladaptive plastic changes in the brain.

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.

The use of benzodiazepines for tinnitus: systematic review

Objectives:

To investigate the effectiveness of benzodiazepine use for subjective tinnitus and to consider this in the context of the concomitant side effects.

Methods:

A systematic search of several databases using the terms ‘tinnitus’ and ‘benzodiazepines’ was conducted to find clinical trials of benzodiazepines and comparators in tinnitus patients. These studies were then assessed for risk of bias.

Results:

Six clinical trials were included. Clonazepam was found to be effective in three studies, but these studies had limitations regarding adequate blinding. The effectiveness of alprazolam was equivocal. Diazepam was not effective in two studies and oxazepam was effective in one study.

Conclusion:

Benzodiazepine use for subjective tinnitus does not have a robust evidence base. Clonazepam has the most evidence to support its use and is relatively less likely to lead to abuse because of its longer half-life, but caution is still needed given the other serious side effects.

Tinnitus

Tinnitus, the perception of sound in the absence of an external sound, usually results from a disorder of: (1) the auditory system (usually peripheral, rarely central); (2) the somatosensory system (head and neck); or (3) a combination of the two. Its cause can be determined through its characteristics. The history must include the tinnitus': (1) quality (including whether it can ever be pulsatile or have a clicking component); (2) location; (3) variability; (4) predominant pitch (low or high); and (5) whether the patient can do something to modulate the percept. In addition to the standard neuro-otologic examination, the exam should include inspection of the teeth for evidence of wear, listening around the ear and neck for sounds similar to the tinnitus, palpation of the craniocervical musculature for trigger points, and probing whether the tinnitus percept can be modulated with "somatic testing." All subjects should have a recent audiogram. Presently the most compelling tinnitus theory is the dorsal cochlear nucleus (DCN) hypothesis: both the auditory and somatosensory systems converge upon and interact within the DCN. If the activity of the DCN's somatosensory-interacting fusiform cells exceeds an individual's tinnitus threshold, then tinnitus results.

Protective effects of Ginkgo biloba extract EGb 761 against noise trauma-induced hearing loss and tinnitus development

Noise-induced hearing loss (NIHL) and resulting comorbidities like subjective tinnitus are common diseases in modern societies. A substance shown to be effective against NIHL in an animal model is the Ginkgo biloba extract EGb 761. Further effects of the extract on the cellular and systemic levels of the nervous system make it a promising candidate not only for protection against NIHL but also for its secondary comorbidities like tinnitus. Following an earlier study we here tested the potential effectiveness of prophylactic EGb 761 treatment against NIHL and tinnitus development in the Mongolian gerbil. We monitored the effects of EGb 761 and noise trauma-induced changes on signal processing within the auditory system by means of behavioral and electrophysiological approaches. We found significantly reduced NIHL and tinnitus development upon EGb 761 application, compared to vehicle treated animals. These protective effects of EGb 761 were correlated with changes in auditory processing, both at peripheral and central levels. We propose a model with two main effects of EGb 761 on auditory processing, first, an increase of auditory brainstem activity leading to an increased thalamic input to the primary auditory cortex (AI) and second, an asymmetric effect on lateral inhibition in AI.