Update on Tinnitus

Transient Delivery of a KCNQ2/3-Specific Channel Activator 1 Week After Noise Trauma Mitigates Noise-Induced Tinnitus

Exposure to loud noise can cause hearing loss and tinnitus in mice and humans. In mice, one major underlying mechanism of noise-induced tinnitus is hyperactivity of auditory brainstem neurons, due at least in part, to decreased Kv7.2/3 (KCNQ2/3) potassium channel activity. In our previous studies, we used a reflex-based mouse model of tinnitus and showed that administration of a non-specific KCNQ channel activator, immediately after noise trauma, prevented the development of noise-induced tinnitus, assessed 1 week after trauma. Subsequently, we developed RL-81, a very potent and highly specific activator of KCNQ2/3 channels. Here, to test the timing window within which RL-81 prevents tinnitus in mice, we modified and employed an operant animal model of tinnitus, where mice are trained to move in response to sound but not move in silence. Mice with behavioral evidence of tinnitus are expected to move in silence. We validated this mouse model by testing the effect of salicylate, which is known to induce tinnitus. We found that transient administration of RL-81 1 week after noise exposure did not affect hearing loss but reduced significantly the percentage of mice with behavioral evidence of tinnitus, assessed 2 weeks after noise exposure. Our results indicate that RL-81 is a promising drug candidate for further development for the treatment of noise-induced tinnitus.

Sex Differences in the Response to Different Tinnitus Treatment

Introduction

Tinnitus is a complex symptom requiring a thorough multidisciplinary assessment to construct an individual’s tinnitus profile. The Antwerp University Hospital hosts a tertiary tinnitus clinic providing intensive, multidisciplinary tinnitus care in the form of combinational psychological treatment with either Tinnitus Retraining Therapy (TRT)/Cognitive Behavioral Therapy (CBT) or TRT/eye movement desensitization and reprocessing therapy (EMDR), high-definition transcranial direct current stimulation (HD-tDCS), and physical therapy treatment (in cases of somatic influence of the neck or the temporomandibular area). Several factors may contribute to therapy effect of which the role of gender has recently gained more interest. As such, the current manuscript explores gender differences in the outcome of different tinnitus treatments.

Methods

Data on treatment outcome of four distinct tinnitus treatments (1. HD-tDCS; 2. orofacial physical therapy; 3. combination TRT + CBT; and 4. combination TRT + EMDR) were pooled and compared. Treatment outcome was assessed via the Tinnitus Functional Index (TFI). Participants completed the TFI at baseline, immediately after treatment and after 9 weeks (±3 weeks) follow-up. To explore the effect of gender on different treatment outcomes, a linear mixed model was designed including Time point, Gender, and Therapy Group as fixed factors as well as all interactions between these factors.

Results

TFI scores improved significantly over time regardless of therapy group (p < 0.0001). A mean TFI decrease of at least 13 points was obtained by all participants except by those in the HD-tDCS. Significant interactions between Gender and Time point were identified in all groups except for the TRT +EMDR group. Female subjects improved more extensively than males in the HD-tDCS (p = 0.0009) and orofacial therapy group (p = 0.0299). Contrarily, in the TRT +CBT group, male participants showed a significant improvement whereas the mean TFI scores of female subjects remained on baseline levels (p = 0.0138).

Conclusion

Our data suggest that male and female tinnitus patients seem to react differently to different therapy options. We strongly encourage further prospective studies to discern the relevance of gender in therapy outcome.

Towards a Mechanistic-Driven Precision Medicine Approach for Tinnitus

In this position review, we propose to establish a path for replacing the empirical classification of tinnitus with a taxonomy from precision medicine. The goal of a classification system is to understand the inherent heterogeneity of individuals experiencing and suffering from tinnitus and to identify what differentiates potential subgroups. Identification of different patient subgroups with distinct audiological, psychophysical, and neurophysiological characteristics will facilitate the management of patients with tinnitus as well as the design and execution of drug development and clinical trials, which, for the most part, have not yielded conclusive results. An alternative outcome of a precision medicine approach in tinnitus would be that additional mechanistic phenotyping might not lead to the identification of distinct drivers in each individual, but instead, it might reveal that each individual may display a quantitative blend of causal factors. Therefore, a precision medicine approach towards identifying these causal factors might not lead to subtyping these patients but may instead highlight causal pathways that can be manipulated for therapeutic gain. These two outcomes are not mutually exclusive, and no matter what the final outcome is, a mechanistic-driven precision medicine approach is a win-win approach for advancing tinnitus research and treatment. Although there are several controversies and inconsistencies in the tinnitus field, which will not be discussed here, we will give a few examples, as to how the field can move forward by exploring the major neurophysiological tinnitus models, mostly by taking advantage of the common features supported by all of the models. Our position stems from the central concept that, as a field, we can and must do more to bring studies of mechanisms into the realm of neuroscience.

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.

A Pilot Genome-Wide Association Study Identifies Potential Metabolic Pathways Involved in Tinnitus

Tinnitus, the perception of an auditory phantom sound in the form of ringing, buzzing, roaring, or hissing in the absence of an external sound source, is perceived by ~15% of the population and 2.5% experiences a severely bothersome tinnitus. The contribution of genes on the development of tinnitus is still under debate. The current manuscript reports a pilot Genome Wide Association Study (GWAS) into tinnitus, in a small cohort of 167 independent tinnitus subjects, and 749 non-tinnitus controls, who were collected as part of a cross-sectional study. After genotyping, imputation, and quality checking, the association between the tinnitus phenotype and 4,000,000 single-nucleotide polymorphisms (SNPs) was tested followed by gene set enrichment analysis. None of the SNPs reached the threshold for genome-wide significance (p < 5.0e–8), with the most significant SNPs, situated outside coding genes, reaching a p-value of 3.4e–7. By using the Genetic Analysis of Complex Traits (GACT) software, the percentage of the variance explained by all SNPs in the GWAS was estimated to be 3.2%, indicating that additive genetic effects explain only a small fraction of the tinnitus phenotype. Despite the lack of genome-wide significant SNPs, which is, at least in part, due to the limited sample size of the current study, evidence was found for a genetic involvement in tinnitus. Gene set enrichment analysis showed several metabolic pathways to be significantly enriched with SNPs having a low p-value in the GWAS. These pathways are involved in oxidative stress, endoplasmatic reticulum (ER) stress, and serotonin reception mediated signaling. These results are a promising basis for further research into the genetic basis of tinnitus, including GWAS with larger sample sizes and considering tinnitus subtypes for which a greater genetic contribution is more likely.

Cost of care for subjective tinnitus in relation to patient satisfaction

OBJECTIVE

A consistent management algorithm for subjective tinnitus remains to be elucidated. Chronic tinnitus yields approximately US$2110 in annual health care costs per patient. However, it is unclear whether spending more in the management of tinnitus equates with greater patient satisfaction. Thus, the aim of this study is to correlate patient satisfaction with patient demographics, provider recommendations, and total health care-related expenditures.

STUDY DESIGN

A retrospective chart review and a patient satisfaction questionnaire.

SETTING

All data were collected from a large Midwestern hospital.

SUBJECTS AND METHODS

Patients were included who presented to the tinnitus clinic during the year 2011 and were between the ages of 18 and 89 years. They were excluded with diagnoses of Ménière's disease, pulsatile tinnitus, acoustic neuromas, or autoimmune inner ear diseases. The retrospective data and satisfaction surveys were entered by 3 of the authors. Responses were based on Likert scales.

RESULTS

Of the 692 patients included, 230 completed and returned the satisfaction questionnaire (33.2% response rate), yielding an overall mean of $662.60 charges. The frequency of intervention recommendations per patients ranged from 0 to 13, with a median of 4. Spearman's correlations did not result in significant correlations between patient satisfaction and number of clinic visits (P=.499) or associated charges (P=.453).

CONCLUSION

Given that the variability among provider recommendations, the high overall mean of tinnitus-related charges, and patient satisfaction was not related to costs, further research is needed examining patient preference in the treatment of tinnitus.

Effect of different sounds on the treatment outcome of tinnitus retraining therapy

OBJECTIVES

The purpose of this study was to evaluate the therapeutic effect of three different types of sounds on tinnitus patients undergoing tinnitus retraining therapy (TRT).

METHODS

This is a single-institution retrospective study, performed in one tertiary otological referral center. Thirty-eight adults with subjective idiopathic tinnitus who were followed for at least 9 weeks were enrolled. Sound therapy was delivered in 3 different ways: narrowband noise TRT (nTRT); mixed band noise TRT (mTRT); broadband noise TRT (bTRT). Treatment response was measured through validated psychometric questionnaires: Tinnitus Handicap Inventory (THI), visual analog scale (VAS) on annoyance, and numerical description of hours of tinnitus perception (awareness hours).

RESULTS

A total of 38 patients were followed for at least 9 weeks. In nTRT group, all outcome measures including THI, VAS, and the awareness hours, decreased over 9 weeks with no statistical significance. In mTRT group, all outcome measures except for awareness hours significantly improved 9 weeks after the beginning of the treatment. In bTRT group, all outcome measures decreased significantly in 9 weeks. When therapeutic success is defined as improvement in THI 7 or more, bTRT group (77.8%) showed a higher success rate than other groups for 38 patients with the minimum follow-up of 9 weeks.

CONCLUSION

All three sounds can provide relief in patients with annoying tinnitus after TRT. However, there is difference in the therapeutic effect according to sound types. Broadband sound seems to be better than narrowband sound or mixed sound in relieving the patients from tinnitus. Therefore, sound therapy with broadband noise may be more appropriate during TRT, but further evidence is needed for precise conclusion.

Prevalence of tinnitus in patients withhypertension and the impact of different anti hypertensive drugs on the incidence of tinnitus: A prospective, single-blind, observational study

BACKGROUND

Tinnitus is a common symptom in audiology and neurologypatients. Controversial data have been reported in the literature about the prevalence of tinnitus in hypertensive patients, whereas its relationship with the extent of blood pressure (BP) control has not been substantially explored.

OBJECTIVE

The aim of this study was to determine the prevalence of tinnitus in hypertensive patients, and the impact of different antihypertensive drugs on the incidence of tinnitus in these patients.

METHODS

This prospective, single-blind, observational study was conducted at the Hypertension Clinic, St. Orsola-Malpighi Hospital, Bologna, Italy. Patients aged 18 to 75 years with uncontrolled hypertension and receiving antihypertensive therapy were enrolled. Patients were asked to complete a standardized questionnaire to assess the presence, frequency, and duration of tinnitus and the apparent effect of their antihypertensive treatment on it. Patients considered by the investigator to have tinnitus, regardless of their audiologic condition, underwent a complete clinical cardiovascular examination, including supine systolic BP (SBP) and diastolic BP measurement and standard 12-lead electrocardiography. Twelve-hour ambulatory BP monitoring was also performed, and patients were asked to record, using patient diaries, times of the onset and resolution of tinnitus that occurred during those 12 hours. From these data, correlations between the onset of tinnitus and BP were calculated.

RESULTS

A total of 476 patients participated in the study (283 men, 193 women). Of these, 84 (17.6%) patients reported occasional or prolonged spontaneous tinnitus, whereas 392 (82.4%) reported no tinnitus. The incidence of tinnitus was significantly higher in patients receiving diuretics (72/265 [27.2%]) compared with those receiving angiotensin lI receptor blockers (5/37 [13.5%]), α-blockers (12/55 [21.8%]), or 3-hydroxy-3-methylglutaryl coenzyme A reduc tase inhibitors (9/73 [12.3%]) (all, P < 0.05). Mean (SD) SBP was significantly higher in patients without tinnitus compared with those with it (143.2 [11.1 ] vs 140.6 [10.3] mm Hg; P < 0.005). In 10 (11.9%) patients with tinnitus, the onset was correlated with a sudden decrease in SBP (<140 mm Hg).

CONCLUSIONS

In this study of tinnitus in patients receiving antihypertensivetherapy, tinnitus was found in 17.6% of patients. Tinnitus was associated with the use of diuretics and with low SBP. Further studies are needed.

Effects of deqi on autonomic balance in adult tinnitus patients: study design of a randomized controlled trial

Background. Recent reports suggest that a proportion of tinnitus patients suffer from mental illness. Autonomic nervous system plays a useful role in tinnitus therapy since electrical vagal nerve stimulation (VNS) has been frequently used to alleviate tinnitus-induced depression in clinic. heart rate variability (HRV), which is reflective of autonomic nervous system function, has been proved to be modulated by acupuncture. In the present study, we aim to compare the effect of deqi sensation on heart rate variability in adult tinnitus patients. Methods. Thirty participants are randomly assigned to verum acupuncture (creating deqi) or shallow acupuncture (not creating deqi) at Baihui (Du-20), Shenting (Du-24), Tinghui (GB-2), Waiguan (SJ-5), and Zulinqi (GB-41) for 3 weeks. The primary outcome measure is heart rate variability, which is measured at the first acupuncture, as well as the last acupuncture. Discussion. Completion of this trial will help to identify the role of deqi sensation in acupuncture effect for tinnitus and reveal an autonomic modulation mechanism for acupuncture effect. Trial Registration. This trial is registered with International Standard Randomised Controlled Trial Number ISRCTN58013563.

Characterization of tinnitus in Nigeria

OBJECTIVE

This study aimed to characterize tinnitus in middle aged and elderly out-patients attending a specialized clinic in a developing country.

METHODS

A cross sectional study of patients attending the ear, nose and throat (ENT) clinic of Olabisi Onabanjo University Teaching Hospital, OOUTH Sagamu, Nigeria. Data was collected with the use of a structured questionnaire. Data collected included socio demographics, medical history including experience of tinnitus, PTAs, BMI and BP. Data was analyzed using SPSS version 17.0.

RESULTS

79 patients had complaints of tinnitus thus making a crude prevalence of 14.5%, the prevalence increased steadily along the age groups. 51.9% of patients experienced tinnitus for a short period. 53.2% of the patients had symptoms referable to only one ear, while 54.4% had discrete as opposed to multiple types of tinnitus. Occurrence of intermittent symptoms was experienced by 75.9% of the patients and 70.9% were non-pulsatile in nature. Tinnitus was significantly associated with abnormal audiographic pattern, global increased hearing thresholds, high tone hearing loss, vertigo, hypertension and obesity.

CONCLUSION

Tinnitus character was majorly short term, unilateral, discrete, intermittent, and non-pulsatile in nature, and it is associated with otological, audiological, anthropometric and cardiovascular anomalies. The characteristics of tinnitus in Nigerian patients were similar to those described in developed countries, but the major risk factors for tinnitus except hearing impairment, may be different from the latter.

Efficacy of myofascial trigger point deactivation for tinnitus control

Chronic pain in areas surrounding the ear may influence tinnitus.

Objective

To investigate the efficacy of myofascial trigger point deactivation for the relief of tinnitus.

Method

A double-blind randomized clinical trial enrolled 71 patients with tinnitus and myofascial pain syndrome. The experimental group (n = 37) underwent 10 sessions of myofascial trigger point deactivation and the control group (n = 34), 10 sessions with sham deactivation.

Results

Treatment of the experimental group was effective for tinnitus relief (p < 0.001). Pain and tinnitus relieves were associated (p = 0.013), so were the ear with worst tinnitus and the side of the body with more pain (p < 0.001). The presence of temporary tinnitus modulation (increase or decrease) upon initial muscle palpation was frequent in both groups, but its temporary decrease was related to the persistent relief at the end of treatment (p = 0.002).

Conclusion

Besides medical and audiological investigation, patients with tinnitus should also be checked for: 1) presence of myofascial pain surrounding the ear; 2) laterality between both symptoms; 3) initial decrease of tinnitus during muscle palpation. Treating this specific subgroup of tinnitus patients with myofascial trigger point release may provide better results than others described so far.

Inhibitory neurotransmission in animal models of tinnitus: maladaptive plasticity

Tinnitus is a phantom auditory sensation experienced by up to 14% of the United States population with a smaller percentage experiencing decreased quality of life. A compelling hypothesis is that tinnitus results from a maladaptive plastic net down-regulation of inhibitory amino acid neurotransmission in the central auditory pathway. This loss of inhibition may be a compensatory response to loss of afferent input such as that caused by acoustic insult and/or age-related hearing loss, the most common causes of tinnitus in people. Compensatory plastic changes may result in pathologic neural activity that underpins tinnitus. The neural correlates include increased spontaneous spiking, increased bursting and decreased variance of inter-spike intervals. This review will examine evidence for chronic plastic neuropathic changes in the central auditory system of animals with psychophysically-defined tinnitus. Neurochemical studies will focus on plastic tinnitus-related changes of inhibitory glycinergic neurotransmission in the adult dorsal cochlear nucleus (DCN). Electrophysiological studies will focus on functional changes in the DCN and inferior colliculus (IC). Tinnitus was associated with increased spontaneous activity and altered response properties of fusiform cells, the major output neurons of DCN. Coincident with these physiologic alterations were changes in glycine receptor (GlyR) subunit composition, its anchoring/trafficking protein, gephyrin and the number and affinity of membrane GlyRs revealed by receptor binding. In the IC, the primary afferent target of DCN fusiform cells, multi-dimensional alterations in unit-spontaneous activity (rate, burst rate, bursting pattern) were found in animals with behavioral evidence of chronic tinnitus more than 9 months following the acoustic/cochlear insult. In contrast, immediately following an intense sound exposure, acute alterations in IC spontaneous activity resembled chronic tinnitus-related changes but were not identical. This suggests that long-term neuroplastic changes responsible for chronic tinnitus are likely to be responsible for its persistence. A clear understanding of tinnitus-related plasticity in the central auditory system and its associated neurochemistry may help define unique targets for therapeutic drug development.

Comparison of Muzzle Suppression and Ear-Level Hearing Protection in Firearm Use

Objective. To compare noise reduction of commercially available ear-level hearing protection (muffs/inserts) to that of firearm muzzle suppressors.

Setting. Experimental sound measurements under consistent environmental conditions.

Subjects. None.

Study Design and Methods. Muzzle suppressors for 2 pistol and 2 rifle calibers were tested using the Bruel & Kjaer 2209 sound meter and Bruel & Kjaer 4136 microphone calibrated with the Bruel & Kjaer Pistonphone using Military-Standard 1474D placement protocol. Five shots were recorded unsuppressed and 10 shots suppressed under consistent environmental conditions. Sound reduction was then compared with the real-world noise reduction rate of the best available ear-level protectors.

Results. All suppressors offered significantly greater noise reduction than ear-level protection, usually greater than 50% better. Noise reduction of all ear-level protectors is unable to reduce the impulse pressure below 140 dB for certain common firearms, an international standard for prevention of sensorineural hearing loss.

Conclusion. Modern muzzle-level suppression is vastly superior to ear-level protection and the only available form of suppression capable of making certain sporting arms safe for hearing. The inadequacy of standard hearing protectors with certain common firearms is not recognized by most hearing professionals or their patients and should affect the way hearing professionals counsel patients and the public.

Diagnosis and management of somatosensory tinnitus: review article

Tinnitus is the perception of sound in the absence of an acoustic external stimulus. It affects 10-17% of the world's population and it a complex symptom with multiple causes, which is influenced by pathways other than the auditory one. Recently, it has been observed that tinnitus may be provoked or modulated by stimulation arising from the somatosensorial system, as well as from the somatomotor and visual-motor systems. This specific subgroup -somatosensory tinnitus - is present in 65% of cases, even though it tends to be underdiagnosed. As a consequence, it is necessary to establish evaluation protocols and specific treatments focusing on both the auditory pathway and the musculoskeletal system.

Characterization of tinnitus in the elderly and its possible related disorders

Population aging it is a current reality in Brazil and tinnitus appears as a very prevalent symptom, having a high impact on the quality of life of elderly patients.

Aim

to evaluate and to characterize tinnitus in this group.

Materials and Methods

A research questionnaire randomly given to 100 elderly patients in a tertiary hospital, asking about tinnitus characteristics, its impact on the life of the patient, and personal medical history.

Results

61% of the participants were female, average age average was 69.53 years.

Conclusions

Tinnitus has a relevant impact on the lives of the elderly; there was no correlation between the level of hearing loss and the level of patient dissatisfaction caused by tinnitus; and presbycusis was the most common finding in the audiometric tests.

Tinnitus in postherpetic neuralgia

We describe a woman who developed postherpetic neuralgia (PHN) located on the skin areas of the left ophthalmic division of the fifth cranial nerve without ocular involvement. PHN was associated with tinnitus, which was located ipsilaterally to the painful side and increased in proportion to the intensity of pain. Tinnitus was responsive to treatment with duloxetine, 60 mg daily, and subsided when the PHN resolved. This is the first description of tinnitus in PHN.

Sensação subjetiva do zumbido pré e pós intervenção nutricional em alterações metabólicas

TEMA: diferentes etiologias estão relacionadas com a presença de zumbido, incluindo doenças metabólicas (glicêmicas e lipídicas). OBJETIVO: comparar o grau de severidade do zumbido por meio de medidas de auto-análise em sujeitos com alterações metabólicas pré e pós-intervenção nutricional, utilizando o Questionário de Gravidade do Zumbido. MÉTODO: vinte e um sujeitos, homens e mulheres, com idade entre 40 e 82 anos, participaram deste estudo. Critérios de inclusão abrangeram a presença de zumbido e de alteração metabólica diagnosticada por meio de exames laboratoriais. Todos os sujeitos foram submetidos a um programa de intervenção nutricional. A avaliação audiológia e o questionário de gravidade de zumbido foram aplicados pré e pós-intervenção. RESULTADOS: comparando os resultados pré e pós-intervenção os dados mostram uma diferença estatisticamente significante com relação à sensação do zumbido em 71,5% dos sujeitos, os quais referiram menor impacto do zumbido nas atividades diárias. CONCLUSÃO: uma importante diferença foi observada com relação à influência do zumbido na vida do sujeito quando utilizadas as medidas de auto-análise. Verificou-se uma relação direta entre zumbido e alterações metabólicas em casos relacionados a estes sintomas.

Plasticity at glycinergic synapses in dorsal cochlear nucleus of rats with behavioral evidence of tinnitus

Fifteen percent to 35% of the United States population experiences tinnitus, a subjective "ringing in the ears". Up to 10% of those afflicted report severe and disabling symptoms. Tinnitus was induced in rats using unilateral, 1 h, 17 kHz-centered octave-band noise (116 dB SPL) and assessed using a gap-startle method. The dorsal cochlear nucleus (DCN) is thought to undergo plastic changes suggestive of altered inhibitory function during tinnitus development. Exposed rats showed near pre-exposure auditory brainstem response (ABR) thresholds for clicks and all tested frequencies 16 weeks post-exposure. Sound-exposed rats showed significantly worse gap detection at 24 and 32 kHz 16 weeks following sound exposure, suggesting the development of chronic, high frequency tinnitus. Message and protein levels of alpha(1-3,) and beta glycine receptor subunits (GlyRs), and the anchoring protein, gephyrin, were measured in DCN fusiform cells 4 months following sound exposure. Rats with evidence of tinnitus showed significant GlyR alpha(1) protein decreases in the middle and high frequency regions of the DCN while alpha(1) message levels were paradoxically increased. Gephyrin levels showed significant tinnitus-related increases in sound-exposed rats suggesting intracellular receptor trafficking changes following sound exposure. Consistent with decreased alpha(1) subunit protein levels, strychnine binding studies showed significant tinnitus-related decreases in the number of GlyR binding sites, supporting tinnitus-related changes in the number and/or composition of GlyRs. Collectively, these findings suggest the development of tinnitus is likely associated with functional GlyR changes in DCN fusiform cells consistent with previously described behavioral and neurophysiologic changes. Tinnitus related GlyR changes could provide a unique receptor target for tinnitus pharmacotherapy or blockade of tinnitus initiation.

Repetitive transcranial magnetic stimulation improve tinnitus in normal hearing patients: a double-blind controlled, clinical and neuroimaging outcome study

BACKGROUND AND PURPOSE

Tinnitus is a frequent disorder which is very difficult to treat and there is compelling evidence that tinnitus is associated with functional alterations in the central nervous system. Targeted modulation of tinnitus-related cortical activity has been proposed as a promising new treatment approach. We aimed to investigate both immediate and long-term effects of low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) in patients with tinnitus and normal hearing.

METHODS

Using a parallel design, 20 patients were randomized to receive either active or placebo stimulation over the left temporoparietal cortex for five consecutive days. Treatment results were assessed by using the Tinnitus Handicap Inventory. Ethyl cysteinate dimmer-single photon emission computed tomography (SPECT) imaging was performed before and 14 days after rTMS.

RESULTS

After active rTMS there was significant improvement of the tinnitus score as compared to sham rTMS for up to 6 months after stimulation. SPECT measurements demonstrated a reduction of metabolic activity in the inferior left temporal lobe after active rTMS.

CONCLUSION

These results support the potential of rTMS as a new therapeutic tool for the treatment of chronic tinnitus, by demonstrating a significant reduction of tinnitus complaints over a period of at least 6 months and significant reduction of neural activity in the inferior temporal cortex, despite the stimulation applied on the superior temporal cortex.

Mechanisms of synaptic plasticity in the dorsal cochlear nucleus: plasticity-induced changes that could underlie tinnitus

PURPOSE

Tinnitus is the persistent perception of a subjective sound. Tinnitus is almost universally experienced in some forms. In most cases, recovery may occur in seconds, hours, or days. How does tinnitus shift from a transient condition to a lifelong disorder? Several lines of evidence, including clinical studies and animal models, indicate that the brain, rather than the inner ear, may in some cases be the site of maintenance of tinnitus. One hypothesis is that normal electrical activity in the auditory system becomes pathologically persistent due to plasticity-like mechanisms that can lead to long-term changes in the communication between neurons. A candidate site for the expression of this so-called synaptic plasticity is a region of the brainstem called the dorsal cochlear nucleus (DCN), a site of integration of acoustic and multimodal, sensory inputs.

CONCLUSIONS

Here we review recent findings on cellular mechanisms observed in the DCN that can lead to long-term changes in the synaptic strength between different neurons in the DCN. These cellular mechanisms could provide candidate signaling pathways underlying the induction (ignition) and/or the expression (maintenance) of tinnitus.

Tinnitus aurium in persons with normal hearing: 55 years later

Objective

The aim of this study was to investigate the effect of silence on the appearance of auditory phantom perceptions in normal-hearing adults, with specific emphasis on the influence of suggestion.

Study Design

Cross-sectional survey.

Subjects and Methods

Fifty-three normal-hearing young Caucasian adults were subjected to two 4-minute sessions in an anechoic sound chamber. In the first session the chamber was empty; in the second session the chamber contained a nonfunctioning loudspeaker. At the end of each session, subjects had to indicate which sounds they perceived from a list of 23 different sounds.

Results

When the loudspeaker was not present, 83 percent of the participants reported that they experienced at least one sound, and the percentage increased to 92 percent when the loudspeaker was present.

Conclusion

These results confirm the emergence of tinnituslike perceptions in a nonclinical population in a silent environment and indicate that suggestive mechanisms play only a minor role in their generation. © 2008 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Genetics of chronic tinnitus

Susceptibility to chronic tinnitus is highly variable and of particular interest when it comes to defining strategies for prevention and treatment. While several rare monogenic disorders have been described that are associated with tinnitus, the genetic underpinnings of the more common forms of the syndrome are still poorly understood. The present article incorporates recent advancements in the field, including the epidemiology of tinnitus in subjects with neuropsychiatric illness, and highlights pilot studies of candidate genes.

Myofascial trigger point:a possible way of modulating tinnitus

In order to investigate whether myofascial trigger points can modulate tinnitus, as well as the association between tinnitus and myofascial trigger points, 94 individuals with and 94 without tinnitus, matched by age and gender, were analyzed by means of bilateral digital pressure of 9 muscles. Temporary modulation of tinnitus was frequently observed (55.9%) during digital pressure, mainly in the masseter. The rate of tinnitus modulation was significantly higher on the same side of the myofascial trigger point subject to examination in 6 out of 9 muscles. An association between tinnitus and the presence of myofascial trigger points was observed (p < 0.001), as well as a laterality association between the ear with the worst tinnitus and the side of the body with more myofascial trigger points (p < 0.001). Thus, this relationship could be explained not only by somatosensory-auditory system interactions but also by the influence of the sympathetic system.

The efficacy of open molds in controlling tinnitus

Hearing aids may be a option to improve tinnitus and hearing loss. Aim: to evaluate tinnitus after one month use of BTE hearing aids with open molds and pressure vent molds in patients with symmetric sensorineural hearing loss. Methods: 50 patients seen at our Tinnitus Clinic who presented bilateral tinnitus and hearing loss underwent a randomized blind crossover clinical trial: 26 first used BTE hearing aids with open molds, and the remaining 24 first used pressure vent molds. After 30 days using the first mold and a wash-out period, the type of earmold was changed and was applied for another 30-day-period. Tinnitus evaluation was done qualitatively (improved, unchanged and worsened) and quantitatively (variation on a numeric scale from 0 to 10). Results: 82% of the cases reported improvement of tinnitus with at least one type of earmold; there was no significant difference in the reduction of discomfort due to tinnitus in the quantitative and qualitative evaluations. Although similar tinnitus control was obtained with both methods, 66% of the patients preferred the open mold. Conclusion: In a short-term evaluation improvement of tinnitus by the use of hearing aids does not depend on earmold ventilation.

Evaluation of white matter structures in patients with tinnitus using diffusion tensor imaging

Recent functional imaging studies have demonstrated that the sensation of tinnitus is associated with activity in cortical regions functionally linked to subserve the generation, perception and processing of the tinnitus stimulus. Previous functional imaging studies have focused primarily on the cortical centers. However, none of these examined the functional nature of associated white matter interconnecting these cortical centers. In this study, we investigate the integrity of white matter tracts interconnecting the auditory system to the parietal and frontal corticies in tinnitus patients using diffusion tensor imaging. Our preliminary results suggest the possible involvement of associated white matter structures in addition to processing cortical centers in tinnitus patients compared with healthy subjects.

Titus's tinnitus

Historical approaches to tinnitus have depended highly on cultural factors. While ancient Oriental mysticism regarded it as sensitivity to the divine, Roman medicine associated it with depressive and seizure disorders on the basis of presumed common pathophysiology shared by the three conditions. In the Babylonian Talmud, tinnitus appears as Titus's curse: a gnat buzzing in the brain, responding to sound therapy, and then habituating. Various sources show varied emphases with common attention for contextual and emotional aspects that have become an important focus in modern management of tinnitus.

Zumbido em pacientes com audiometria normal: caracterização clínica e repercussões

Pacientes com zumbido e audiometria normal constituem um grupo importante, pois seus achados não sofrem influência da perda auditiva. Apesar disso, este grupo é pouco estudado e não sabemos se suas características clínicas e repercussões são semelhantes às dos indivíduos com perda auditiva. OBJETIVOS: Comparar as características clínicas do zumbido e sua interferência nas atividades diárias em pacientes com e sem perda auditiva. FORMA DE ESTUDO: coorte histórica. MATERIAL E MÉTODO: Entre 744 pacientes atendidos no Grupo de Pesquisa em Zumbido do HCFMUSP, avaliou-se retrospectivamente com um corte transversal os 55 indivíduos com audiometria tonal normal. O grupo controle correspondeu a 198 pacientes com zumbido e perda auditiva atendidos sob o mesmo protocolo. Analisou-se os dados dos pacientes, as características clínicas do zumbido e sua repercussão na vida do paciente. RESULTADOS: A idade média no grupo de estudo (43,1 ± 13,4 anos) foi significantemente menor do que a do grupo controle (49,9 ± 14,5 anos). Em ambos os grupos houve predomínio do sexo feminino e o zumbido foi predominantemente bilateral, único e constante, porém sem diferença entre os grupos. A interferência na concentração e no equilíbrio emocional foi significantemente menor no grupo de estudo (25,5% e 36,4%) do que no controle (46% e 61,6%), porém sem diferença quanto à interferência no sono e na atividade social. CONCLUSÕES: O grupo de pacientes com zumbido e audição normal apresentou características clínicas semelhantes em relação ao grupo com perda auditiva. Entretanto, a faixa etária acometida e a interferência sobre a concentração e o equilíbrio emocional foram significantemente menores nestes.

Tinnitus in normally hearing patients: clinical aspects and repercussions

Patients with tinnitus and normal hearing constitute an important group, given that findings do not suffer influence of the hearing loss. However, this group is rarely studied, so we do not know whether its clinical characteristics and interference in daily life are the same of those of the patients with tinnitus and hearing loss. Aim: To compare tinnitus characteristics and interference in daily life among patients with and without hearing loss. Study design: historic cohort. Material and Method: Among 744 tinnitus patients seen at a Tinnitus Clinic, 55 with normal audiometry were retrospectively evaluated. The control group consisted of 198 patients with tinnitus and hearing loss, following the same protocol. We analyzed the patients’ data as well as the tinnitus characteristics and interference in daily life. Results: The mean age of the studied group (43.1 ± 13.4 years) was significantly lower than that of the control group (49.9 ± 14.5 years). In both groups, tinnitus was predominant in women, bilateral, single tone and constant, but there were no differences between both groups. The interference in concentration and emotional status (25.5% and 36.4%) was significantly lower in the studied group than that of the control group (46% and 61.6%), but it did not happen in regard to interference over sleep and social life. Conclusions: Patients with tinnitus and normal hearing showed similar characteristics when compared to those with hearing loss. However, the age of the patients and the interference over concentration and emotional status were significantly lower in this group.

Effects of Concurrent Noise and Jet Fuel Exposure on Hearing Loss

We sought to examine the effects of occupational exposure to jet fuel on hearing in military workers.

METHODS

Noise-exposed subjects, with or without jet fuel exposure, underwent hearing tests. Work histories, recreational exposures, protective equipment, medical histories, alcohol, smoking, and demographics were collected by questionnaire. Jet fuel, solvent, and noise exposure data were collected from records. Fuel exposure estimates were less than 34% of the OSHA Threshold Limit Values.

RESULTS

Subjects with 3 years of jet fuel exposure had a 70% increase in adjusted odds of hearing loss (OR = 1.7; 95% CI = 1.14-2.53) and the odds increased to 2.41 (95% CI = 1.04-5.57) for 12 years of noise and fuel exposure.

CONCLUSIONS

These findings suggest that jet fuel has a toxic affect on the auditory system.

Oscillucusis and sudden deafness in a migraine patient

Migraine is a complex disease that includes neurologic, gastrointestinal and autonomic symptoms, although headache is most common feature. In a portion of cases headache is preceded by focal neurologic symptoms termed auras. Auditory symptoms only rarely occur as part of an aura. We describe a patient whose 13-year migraine history that included the abnormal perception an oscillation of the intensity of ambient sounds (oscillucusis). During a migraine attack immediately after oscillucusis, the patient developed acute and permanent sudden deafness. Clinical and neurologic examinations revealed only profound hearing loss in her left ear. Audiometric testing confirmed the sensorineural nature of the hearing loss. The clinical aspects and physiopathology of auditory symptoms in this case and in patients with migraine is reviewed.

Clinical Associations Between Tinnitus and Chronic Pain

OBJECTIVE: We sought to estimate the prevalence and severity of tinnitus in patients with chronic pain.

STUDY DESIGN AND SETTING: We conducted a prospective nonrandomized study in which a survey and the Tinnitus Handicap Inventory (THI) were distributed at a tertiary chronic pain clinic.

RESULTS: Seventy-two patients participated. 50 women (mean age, 53 years) and 22 men (mean age, 47.5 years); 54.2% reported having tinnitus. There was an even distribution of patients reporting the onset of tinnitus as before versus after the onset of pain. Four patients reported a direct association between tinnitus and pain. The mean THI score was 27 (of 100) (n = 35). Fifteen subjects scored less than 16, indicating no handicap, and 4 scored over 58, indicating a severe handicap.

CONCLUSION: The study results suggest a high incidence of tinnitus within this population. There were few strong associations between pain and tinnitus. Tinnitus does not significantly handicap the majority of these patients.

SIGNIFICANCE: Tinnitus is a common symptom in the chronic pain population but is not a significant problem for these patients.

Alternative medications and other treatments for tinnitus: facts from fiction

Tinnitus is a significant medical problem affecting approximately 50 million Americans, 12 million of them severely. Once a thorough evaluation has been performed by a qualified otolaryngologist, and no life-threatening pathology has been identified, the opportunity for treatment exists. Treatment options are extensive and range from approved protocols to anecdotal remedies. Although tinnitus may not miraculously disappear, many therapeutic options exist that may help to make the tinnitus more manageable.

Long-term reductions in tinnitus severity

BACKGROUND: This study was undertaken to assess long-term changes in tinnitus severity exhibited by patients who completed a comprehensive tinnitus management program; to identify factors that contributed to changes in tinnitus severity within this population; to contribute to the development and refinement of effective assessment and management procedures for tinnitus. METHODS: Detailed questionnaires were mailed to 300 consecutive patients prior to their initial appointment at the Oregon Health & Science University Tinnitus Clinic. All patients were then evaluated and treated within a comprehensive tinnitus management program. Follow-up questionnaires were mailed to the same 300 patients 6 to 36 months after their initial tinnitus clinic appointment. RESULTS: One hundred ninety patients (133 males, 57 females; mean age 57 years) returned follow-up questionnaires 6 to 36 months (mean = 22 months) after their initial tinnitus clinic appointment. This group of patients exhibited significant long-term reductions in self-rated tinnitus loudness, Tinnitus Severity Index scores, tinnitus-related anxiety and prevalence of current depression. Patients who improved their sleep patterns or Beck Depression Inventory scores exhibited greater reductions of tinnitus severity scores than patients who continued to experience insomnia and depression at follow-up. CONCLUSIONS: Individualized tinnitus management programs that were designed for each patient contributed to overall reductions in tinnitus severity exhibited on follow-up questionnaires. Identification and treatment of patients experiencing anxiety, insomnia or depression are vital components of an effective tinnitus management program. Utilization of acoustic therapy also contributed to improvements exhibited by these patients.

Cortical networks subserving the perception of tinnitus--a PET study

Subjective tinnitus is an auditory phantom perception that may arise from any aberrant signal within the auditory system. Further processing of this signal and the conscious perception of tinnitus takes place in the cerebral cortex. A few functional brain-imaging studies have been performed to elucidate the underlying cerebral mechanisms of this perception. These studies mostly concern rare types of tinnitus (e.g. tinnitus changeable by oral-facial movements), or compared tinnitus patients with healthy volunteers. These studies attributed variable activation of the primary auditory cortices, associative auditory cortices and the left hippocampus to the perception of tinnitus. Based on these heterogeneous results, no consensus on the underlying mechanisms has been reached. The aim of the present study was to obtain further details of the central perception and processing of the tinnitus signal. Positron emission tomography (PET) was used to map the tinnitus-specific central activity. By contrasting PET-images of suppressed tinnitus with PET-images of the habitual tinnitus sensation, we were able to identify a right prefrontal-temporal network associated with the perception of tinnitus. Besides the evidence of activation of associative auditory sensory regions, the results indicated that activation of cortical centres subserving attention and emotion may underlie the continuous irritability associated with severe tinnitus.

Distinguishing levels of tinnitus distress

Degrees of tinnitus distress were explored in a sample of 216 patients who completed audiological measures and were assessed in a structured interview conducted by a clinical psychologist. The Klockhoff and Lindblom grading system was used and its inter-rater reliability assessed in a subsample showing a high degree of correspondence. Results from the interview are reported in terms of variability of tinnitus, characteristics of problematic situations, distress caused by tinnitus, possibilities to cope, and other influencing factors. Finally, a set of discriminant analyses were conducted on the data set resulting in a final model which included pitch, minimal masking level (MML), tolerance in relation to onset, and avoidance of situations because of tinnitus. This model correctly classified 73% of the subjects into the two levels of distress (grade II and III). There may be a potential role for MML as an outcome variable in tinnitus treatment research.

Positron emission tomography of cortical centers of tinnitus

Tinnitus is associated with a wide variety of disorders in the auditory system. Whether generated peripherally or centrally, tinnitus is believed to be associated with activity in specific cortical regions. The present study tested the hypothesis that these cortical centers subserve the generation, perception and processing of the tinnitus stimulus and that these processes are suppressed by lidocaine and masking. Positron emission tomography was used to map the tinnitus-specific central activity. By subtracting positron emission tomography images of regional cerebral blood flow distribution obtained during suppression of the tinnitus from positron emission tomography images obtained during the habitual tinnitus sensation, we were able to identify brain areas concerned with the cerebral representation of tinnitus. Increased neuronal activity caused by tinnitus occurred predominantly in the right hemisphere with significant foci in the middle frontal and middle temporal gyri, in addition to lateral and mesial posterior sites. The results are consistent with the hypothesis that the sensation of tinnitus is associated with activity in cortical regions functionally linked to subserve attention, emotion and memory. For the first time, the functional anatomy of conditions with and without the habitual tinnitus sensation was obtained and compared in the same subjects.

Auditory cortical plasticity: a comparison with other sensory systems

The auditory cortex has a crucial role in higher cognitive functions, including the perception of speech, music and auditory space. Cortical plasticity, as in other sensory systems, is used in the fine tuning of the auditory system for these higher functions. Auditory cortical plasticity can also be demonstrated after lesions of the cochlea and it appears to participate in generating tinnitus. Early musical training leads to an expansion in the representation of complex harmonic sounds in the auditory cortex. Similarly, the early phonetic environment has a strong influence on speech development and, presumably, on the cortical organization of speech. In auditory spatial perception, the spectral cues generated by the head and outer ears vary between individuals and have to be calibrated by learning, which most probably takes place at the cortical level. The neural mechanisms of plasticity are likely to be the same across all cortical regions. It should be useful, therefore, to relate some of the findings and hypotheses about auditory cortical plasticity to previous studies of other sensory systems.

Effect of melatonin on tinnitus

OBJECTIVE

Evaluate melatonin as a treatment for subjective tinnitus.

STUDY DESIGN

Randomized, prospective, double-blind, placebo-controlled crossover trial. Patients were given 3.0 mg melatonin, which was taken nightly for 30 days followed or preceded by a placebo nightly for 30 days, with a 7-day washout period between medications.

SETTING

Outpatient, private, neurotology practice.

PATIENTS

Thirty patients with subjective tinnitus.

MAIN OUTCOME MEASURES

Tinnitus matching, Tinnitus Handicap Inventory (THI), patient questionnaire and interview.

RESULTS

The average pretreatment THI score was 33.91 as compared with 26.43 after the placebo and 26.09 after melatonin. The difference in the THI scores between melatonin and placebo treatment were not statistically significant. The average pretreatment THI score for patients who reported overall improvement with melatonin was statistically higher (P = 0.02) than the average pretreatment THI score for patients who reported no improvement with melatonin. Among subjects reporting difficulty sleeping attributable to their tinnitus, 46.7% reported an overall improvement after melatonin compared with 20.0% for placebo (P = 0.04). There was also a statistically significant difference in improvement with melatonin for those patients with bilateral tinnitus compared with those with unilateral tinnitus (P = 0.02).

CONCLUSION

Melatonin has been shown to be useful in the treatment of subjective tinnitus. Patients with high THI scores and/or difficulty sleeping are most likely to benefit from treatment with melatonin. In light of its minimal side effects, melatonin should be a part of the physician's armamentarium in the treatment of tinnitus.