Evaluation of vardenafil for the treatment of subjective tinnitus: a controlled pilot study

Can Assessment of Rheological Properties of Whole Blood and Plasma Be Useful in the Diagnosis of Tinnitus? A Pilot Study

Tinnitus is a sensation of ringing in the ears in the absence of any physical source in the environment. Between 9-35% of adults experience some form of tinnitus. Common causes of tinnitus include noise, head injury, ototoxic substances, as well as disorders of blood and blood vessels. Vascular causes include: head-neck tumours, turbulent blood flow, problems with blood supply and inner ear cell damage. The aspect of rheology in terms of tinnitus has not been described yet. In the present study, which comprised 12 patients aged 30 to 74 years presenting with tinnitus, rheological properties of whole blood and plasma were assessed. All the subjects underwent audiological and neurological evaluation. The Quemada model was used to describe the variability of red blood cell shape, as well as their tendency to form aggregates. On the basis of the experimental study, statistically different results of haemorheological measurements were observed in the evaluated group in comparison to a reference group.

Evidence for biological markers of tinnitus: A systematic review

Subjective tinnitus is a phantom sound heard only by the affected person and may be a symptom of various diseases. Tinnitus diagnosis and monitoring is based on subjective audiometric and psychometric methods. This review aimed to synthesize evidence for tinnitus presence or its severity. We searched several electronic databases, citation searches of the included primary studies through Web of Science, and further hand searches. At least two authors performed all systematic review steps. Sixty-two records were included and were categorized according the biological variable. Evidence for possible tinnitus biomarkers come from oxidative stress, interleukins, steroids and neurotransmitters categories. We found conflicting evidence for full blood count, vitamins, lipid profile, neurotrophic factors, or inorganic ions. There was no evidence for an association between tinnitus and the remaining categories. The current review evidences that larger studies, with stricter exclusion criteria and powerful harmonized methodological design are needed. Protocol published on PROSPERO (CRD42017070998).

Association between Anatomical Features of Petrotympanic Fissure and Tinnitus in Patients with Temporomandibular Joint Disorder Using CBCT Imaging: An Exploratory Study

Mandible displacement is known to correlate with otological conditions such as pain in the ear canal, hearing loss, or tinnitus. The present work aimed to determine the association between the displacement of the condyle in a temporomandibular joint, the structure and position of the petrotympanic fissure (PTF), and comorbid tinnitus in patients affected by temporomandibular joint and muscle disorder (TMD). We enrolled 331 subjects with TMD (268 women and 63 men). The average age of women was 40.8 ± 16.8 years (range 13–88), whereas the average age of the examined men was 38 ± 14 years (range 13–74). We performed imaging studies of the facial part of the skull in the sagittal plane using a volumetric imaging method and a large imaging field (FOV) of 17 cm × 23 cm. The habitual position of the mandible was determined and used as a reference. Based on the imaging results, we developed a classification for the topography and the structure of the petrotympanic fissure. Thirty-three TMD patients (about 10% of the sample) reported having tinnitus. These patients had PTF configurations characterized by a rear (36.59%) or intracranial-cranial (63.41%) condylar displacement of the temporomandibular joint. Our findings imply that the TMJ- and tinnitus-positive group of patients possibly represents a distinct phenotype of tinnitus. We concluded that for such patients, the therapeutic approach for tinnitus should include TMD treatment.

Nitric oxide increases gain in the ventral cochlear nucleus of guinea pigs with tinnitus

Previous work has led to the hypothesis that, during the production of noise-induced tinnitus, higher levels of nitric oxide (NO), in the ventral cochlear nucleus (VCN), increase the gain applied to a reduced input from the cochlea. To test this hypothesis, we noise-exposed 26 guinea pigs, identified evidence of tinnitus in 12 of them and then compared the effects of an iontophoretically applied NO donor or production inhibitor on VCN single unit activity. We confirmed that the mean driven firing rate for the tinnitus and control groups was the same while it had fallen in the non-tinnitus group. By contrast, the mean spontaneous rate had increased for the tinnitus group relative to the control group, while it remained the same for the non-tinnitus group. A greater proportion of units responded to exogenously applied NO in the tinnitus (56%) and non-tinnitus groups (71%) than a control population (24%). In the tinnitus group, endogenous NO facilitated the driven firing rate in 37% (7/19) of neurons and appeared to bring the mean driven rate back up to control levels by a mechanism involving N-methyl-D-aspartic acid (NMDA) receptors. By contrast, in the non-tinnitus group, endogenous NO only facilitated the driven firing rate in 5% (1/22) of neurons and there was no facilitation of driven rate in the control group. The effects of endogenous NO on spontaneous activity were unclear. These results suggest that NO is involved in increasing the gain applied to driven activity, but other factors are also involved in the increase in spontaneous activity.

Phosphodiesterase-5 (PDE-5) Inhibitors and Ototoxicity: A Systematic Review

OBJECTIVE

This study explores the current literature regarding associations between phosphodiesterase-5 (PDE-5) inhibitors and ototoxicity and provides a detailed summary and discussion of the findings.

DATA SOURCES

A comprehensive electronic search of PubMed/MEDLINE, Scopus, and Cochrane Library for studies published from database inception through March 21, 2018.

STUDY SELECTION

Basic science articles, epidemiological studies, randomized controlled trials, cohort studies, case reports, reviews, meta-analyses, press releases, and newsletters were included. The PRISMA search strategy was used to select papers. Search terms are included in the appendix (http://links.lww.com/MAO/A733).

RESULTS

Twenty-two articles met the inclusion criteria. Among case reports, there were a total of nine patients, all male, with an average age of 57.4 years (37-79 years, SD = 13.87 years). Of the cases of hearing loss, 25% (2/8 cases) were bilateral and 75% (6/8) were unilateral; 22% (2/9) were associated with tinnitus; and 33% (3/9) had accompanying vestibular symptoms (including vertigo and dizziness). Among multipatient studies, all prospective studies failed to find a significant association between ototoxicity and PDE-5 inhibitor use. Results of the retrospective studies were also heterogeneous. Many key molecules in the PDE-5 inhibition pathway have been demonstrated to exist in the cochlea. However, mirroring the clinical studies, the basic science mechanisms have suggested both ototoxic and otoprotective effects.

CONCLUSIONS

Currently, the literature is inconclusive regarding the interaction between PDE-5 inhibitor use and ototoxicity. Future study such as a double-blinded placebo controlled randomized trial with audiometric assessment would provide more sound evidence. Similarly, a unified molecular model is necessary.

Is there an association between the parameters of arterial stiffness and tinnitus?

Background: Increasing arterial stiffness is associated with atherosclerosis and there is an association between atherosclerosis and tinnitus may occur.Objectives: The aim of this study was to investigate the relationship between arterial stiffness and tinnitus using the central pulse-wave analysis method.Methods: This prospective, single center study included 98 participants, comprising 49 patients diagnosed with subjective idiopathic tinnitus (Group 1) and a control group of 49 healthy subjects (Group 2). The Mobil-O-Graph 24 h Pulse wave analysis (PWA) Monitor (I.E.M. GmbH, Stolberg, Germany) was used to determine the arterial stiffness and cardiovascular hemodynamic parameters. Central pulse pressure (CPP), Augmentation index and pulse wave velocity (PWV) were obtained with the device.Results: No statistically significant difference was determined between Groups in respect of age, smoking and hypertension (p > .05). Statistically significantly higher Central Pulse Pressure (CPP) values and pulse wave velocity were higher in Group 1 compared to the control group (p < .005). No statistical variation was detected in terms of the augmentation index (18.5 ± 11.3 vs 16.7 ± 10.3, p = .543).Conclusion: Our results marked that arterial stiffness is associated with tinnitus. The relationship was examined via oscillometric method, which is simple to perform and has been recommended in guidelines for the determination of cardiovascular event risk.

Clinical practice guidelines for diagnosis and treatment of chronic tinnitus in Japan

Clinical practice guidelines in Japan for tinnitus were published in May 2019. Effective treatment of tinnitus contributes to quality of life and may improve depression, anxiety, and cognitive function. The highest priority of treatment recommended by this guideline involves educational counseling, including an explanation of the mechanisms of tinnitus. Understanding tinnitus pathology has also been reported to be a therapeutically effective educational counseling strategy. Further, explaining how sound therapy such as tinnitus retraining therapy (TRT) works is effective. Psychological and cognitive behavioral therapies may be an option. Here, the hearing aid is coupled with a sound generator in order to administer sound therapy for patients with more-severe symptoms. In Japan, it can be difficult to perform psychotherapy alongside otorhinolaryngology, and exemplary sound therapy is more likely to be carried out. In any case, the purpose of treatment is not to eliminate tinnitus, but rather reduce distress that manifests in response to tinnitus by promoting sensory adaptation. Clinically, the most important subject is not the loudness of tinnitus, but the severity of tinnitus distress. TRT consists of educational counseling and sound therapy. The tinnitus handicap inventory (THI) is used to measure the distress level for tinnitus and to determine treatment priorities. Rehabilitation of tinnitus is important because anxiety and depression are often observed in patients with severe tinnitus. Additionally, drug administration should be avoided. As a surgical treatment, a cochlear implant can affect tinnitus symptoms. It is essential to establish a treatment policy according to the disease condition and degree of distress.

Therapeutic Approaches to the Treatment of Tinnitus

Tinnitus is a highly prevalent condition that is associated with hearing loss in most cases. In the absence of external stimuli, phantom perceptions of sounds emerge from alterations in neuronal activity within central auditory and nonauditory structures. Pioneering studies using lidocaine revealed that tinnitus is susceptible to pharmacological interventions. However, lidocaine is not effective in all patients, and no other drug has been identified with clear efficacy for the long-term treatment of tinnitus. In this review, we present recent advances in tinnitus research, including more detailed knowledge of its pathophysiology and involved neurotransmitter systems. Moreover, we summarize results from animal and clinical treatment studies as well as from studies that identified tinnitus as a side effect of pharmacological treatments. Finally, we focus on challenges in the development of pharmacological compounds for the treatment of tinnitus, namely the limitations of available animal models and of standardized clinical research methodologies.

Audiometry results and TEOAE and DPOAE amplitudes in men taking a phosphodiesterase type 5 inhibitor for erectile dysfunction

We conducted a prospective study of transient evoked otoacoustic emissions (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs) in men who were taking an oral phosphodiesterase type 5 (PDE5) inhibitor for erectile dysfunction. Our study group was made up of 30 men (60 ears), aged 34 to 60 years (mean: 50.9). They were randomly divided into three groups; 10 men were given sildenafil (Viagra) at 50 mg twice a week, 10 were given tadalafil (Cialis) at 20 mg twice a week, and 10 were given vardenafil (Levitra) at 20 mg twice a week. All patients took their drug for 3 weeks, for a total of 6 tablets for each patient. Audiometric tests and TEOAE and DPOAE measurements were performed before and after treatment. Post-treatment audiometry demonstrated improvement in hearing in all three groups. However, post-treatment TEOAE amplitudes and DPOAE amplitudes differed among the three groups; they were significantly higher in the sildenafil group at 1.0 kHz and the same in the tadalafil group; in the vardenafil group, the DPOAE amplitude was significantly lower at 3.0 kHz while there was no change in the TEOAE amplitude. We speculate that the possible mechanism for these findings is that PDE5 inhibitors block degradation of cyclic guanosine monophosphate (cGMP) and induce dilation of the cochlear microcirculation, resulting in an increase in cochlear blood flow. We also believe that the decrease in DPOAE amplitudes at 3.0 kHz seen in the vardenafil group may be related to an accumulation of nitric oxide/cGMP complex, which is toxic to the cochlea; however, since there was no change in TEOAE amplitude in the vardenafil group, this influence may be minimal. Further studies are needed to obtain a more comprehensive assessment of the effects of PDE5 inhibitors on hearing with the use of higher doses and longer durations of therapy.

Relationship between increased carotid artery stiffness and idiopathic subjective tinnitus

Tinnitus is defined as perception of sound with no external stimulus, and can separate into pulsatile and non-pulsatile types. Arterial stiffness is a parameter that can predict the cardiovascular event and associated with incidence of stroke. It has been shown that increased arterial stiffness may lead to microvascular damage in brain. Our aim was to assess the arterial stiffness of the carotid system in the development and severity of idiopathic subjective tinnitus. Forty subjective tinnitus patients and 40 age- and sex-matched controls were enrolled in the study. The parameters obtained from the participants included pure tone hearing (dB), serum lipid profile (mg/dl), fasting glucose (mg/dl), blood pressure (mmHg), and body mass index (BMI, kg/m²). The common carotid artery (CCA) stiffness index, Young's elastic modulus (YEM), common carotid intima-media thickness (CIMT), peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI), pulsatility index (PI), vessel diameter, mean velocity (MV), and volume flow (VF) were measured in both the right and left common carotid arteries in both groups. The CCA stiffness index, YEM measurements, right CIMT, and left PI were found to be significantly higher in the patients than those in the control group (p < 0.05). With regard to the severity of the tinnitus and the patient characteristics, there was a significant positive correlation with the CCA stiffness index, YEM measurements, left CIMT, and neutrophil-to-lymphocyte ratio (NLR). However, only the right and left CCA stiffness parameters were found to be statistically significant in the multivariate analysis as independent predictors of a moderate to high degree of tinnitus. The increased stiffness index of the common carotid arteries was significantly associated with the formation and severity of tinnitus. Therefore, an assessment of the carotideal system may be helpful in these patients.

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).

Systematic review of outcome domains and instruments used in clinical trials of tinnitus treatments in adults

BACKGROUND

There is no evidence-based guidance to facilitate design decisions for confirmatory trials or systematic reviews investigating treatment efficacy for adults with tinnitus. This systematic review therefore seeks to ascertain the current status of trial designs by identifying and evaluating the reporting of outcome domains and instruments in the treatment of adults with tinnitus.

METHODS

Records were identified by searching PubMed, EMBASE CINAHL, EBSCO, and CENTRAL clinical trial registries (ClinicalTrials.gov, ISRCTN, ICTRP) and the Cochrane Database of Systematic Reviews. Eligible records were those published from 1 July 2006 to 12 March 2015. Included studies were those reporting adults aged 18 years or older who reported tinnitus as a primary complaint, and who were enrolled into a randomised controlled trial, a before and after study, a non-randomised controlled trial, a case-controlled study or a cohort study, and written in English. Studies with fewer than 20 participants were excluded.

RESULTS

Two hundred and twenty-eight studies were included. Thirty-five different primary outcome domains were identified spanning seven categories (tinnitus percept, impact of tinnitus, co-occurring complaints, quality of life, body structures and function, treatment-related outcomes and unclear or not specified). Over half the studies (55 %) did not clearly define the complaint of interest. Tinnitus loudness was the domain most often reported (14 %), followed by tinnitus distress (7 %). Seventy-eight different primary outcome instruments were identified. Instruments assessing multiple attributes of the impact of tinnitus were most common (34 %). Overall, 24 different patient-reported tools were used, predominantly the Tinnitus Handicap Inventory (15 %). Loudness was measured in diverse ways including a numerical rating scale (8 %), loudness matching (4 %), minimum masking level (1 %) and loudness discomfort level (1 %). Ten percent of studies did not clearly report the instrument used.

CONCLUSIONS

Our findings indicate poor appreciation of the basic principles of good trial design, particularly the importance of specifying what aspect of therapeutic benefit is the main outcome. No single outcome was reported in all studies and there was a broad diversity of outcome instruments.

PROSPERO REGISTRATION

The systematic review protocol is registered on PROSPERO (International Prospective Register of Systematic Reviews): CRD42015017525 . Registered on 12 March 2015 revised on 15 March 2016.

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.

[Pharmacotherapy of acute and chronic hearing loss]

The aetiology of acute hearing loss is mostly idiopathic like sudden sensorineural hearing loss and rarely infectious or vascular. Several studies and meta-analyses of pharmacotherapy are reviewed: In chronic tinnitus there is no indication for pharmacotherapy; sometimes a possible psychosomatic comorbidity has to be treated with psychopharmaceutical agents. Despite a low level of evidence treatment with steroids and initially plasma expanding infusions is recommended for acute tinnitus if there is no spontaneous remission. Intratympanic steroid therapy can be used as an alternative if there is severe hearing loss together with tinnitus.

Measuring disease-specific health-related quality of life to evaluate treatment outcomes in tinnitus patients: A systematic review

OBJECTIVE: To identify all disease-specific health-related quality-of-life (HR-QoL) instruments used to assess tinnitus in clinical trials and detail their psychometric properties.

DATA SOURCES: A literature search was performed in the bibliographical databases of PubMed and Embase to identify all articles using specific HR-QoL instruments in tinnitus trials.

REVIEW METHODS: The HR-QoL instruments used in these articles were investigated in more detail, focusing on characteristics and psychometric values by two independent reviewers.

RESULTS: Seventeen studies were identified by the systematic search. The most used HR-QoL questionnaire was the Tinnitus Questionnaire, followed by the Tinnitus Handicap Inventory, the Tinnitus Reaction Questionnaire, and the Tinnitus Handicap Questionnaire. Internal consistency (Cronbach's α > 0.9) and reproducibility (> 0.8) were high for all questionnaires, and there was heterogeneity in responses between patients, endorsing the use of these questionnaires for discriminative purposes. However, the responsiveness, i.e., the usefulness of these questionnaires in evaluating treatment effects, is not known yet.

CONCLUSION: The HR-QoL instruments used in tinnitus trials appear not to be validated to measure effectiveness of interventions. Using tests or instruments that are valid and reliable is a crucial component of research quality, and both should therefore be studied before final conclusions can be drawn from the questionnaires in upcoming clinical trials.

© 2010 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.

Efficacy and safety of bilateral continuous theta burst stimulation (cTBS) for the treatment of chronic tinnitus: design of a three-armed randomized controlled trial

BACKGROUND

Tinnitus, the perception of sound and noise in absence of an auditory stimulus, has been shown to be associated with maladaptive neuronal reorganization and increased activity of the temporoparietal cortex. Transient modulation of tinnitus by repetitive transcranial magnetic stimulation (rTMS) indicated that these areas are critically involved in the pathophysiology of tinnitus and suggested new treatment strategies. However, the therapeutic efficacy of rTMS in tinnitus is still unclear, individual response is variable, and the optimal stimulation area disputable. Recently, continuous theta burst stimulation (cTBS) has been put forward as an effective rTMS protocol for the reduction of pathologically enhanced cortical excitability.

METHODS

48 patients with chronic subjective tinnitus will be included in this randomized, placebo controlled, three-arm trial. The treatment consists of two trains of cTBS applied bilaterally to the secondary auditory cortex, the temporoparietal associaction cortex, or to the lower occiput (sham condition) every working day for four weeks. Primary outcome measure is the change of tinnitus distress as quantified by the Tinnitus Questionnaire (TQ). Secondary outcome measures are tinnitus loudness and annoyance as well as tinnitus change during and after treatment. Audiologic and speech audiometric measurements will be performed to assess potential side effects. The aim of the present trail is to investigate effectiveness and safety of a four weeks cTBS treatment on chronic tinnitus and to compare two areas of stimulation. The results will contribute to clarify the therapeutic capacity of rTMS in tinnitus.

TRIAL REGISTRATION

The trial was registered with the clinical trials register of http://www.clinicaltrials.gov (NCT00518024).

PHARMACOLOGICAL TREATMENTS FOR TINNITUS: NEW AND OLD

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