Hearing Aids Mitigate Tinnitus, But Does It Matter if the Patient Receives Amplification in Accordance With Their Hearing Impairment or Not? A Meta-Analysis

Predictors of Tinnitus Symptom Relief With Hearing Aids in a European Multicenter Study

OBJECTIVES

Hearing aids (HAs) are a widely accepted first-line treatment option for individuals suffering from both hearing loss and chronic tinnitus. Though HAs are highly effective at improving speech understanding, their effectiveness in ameliorating tinnitus symptoms is less clear. In recent years, several investigators have reported on attempts to predict HAs effectiveness on tinnitus symptoms using an array of variables. These included tinnitus attributes (e.g., frequency, loudness, character), audiological characteristics (e.g., degree and configuration of hearing loss), or HA signal processing parameters (e.g., gain, noise reduction processing). The aims of this study were to determine whether (1) HA usage improves tinnitus-related distress and subjective tinnitus loudness and, if so, whether (2) tinnitus frequency, degree of hearing loss, HA-use time, and the accuracy of the HA fitting influence this effect.

DESIGN

Participants were recruited as part of the "Unification of Treatments and Interventions for Tinnitus Patients (UNITI)" study, a large multicenter randomized controlled trial conducted across five European study sites. Here, we report on the 60 participants with chronic tinnitus and mild-to-moderate hearing loss that were randomized to the HAs-only treatment arm of UNITI. HAs were programmed according to the National Acoustic Laboratories-Nonlinear 2 or Desired Sensation Level ((i/o) v.5) prescriptive formulas and the fitting was verified using in-situ verification. Subsequently, participants underwent a 12-week treatment phase. Improvements in tinnitus-related distress measured with the Tinnitus Handicap Inventory (THI) and the Tinnitus Functional Index (TFI), as well as subjective tinnitus loudness (dB HL), were assessed after 6 and 12 weeks of treatment. Accuracy of the HA fitting was operationalized as the deviation of in-situ measured real ear-aided response from target real ear-aided response parameters, as specified by the respective prescriptive formula.

RESULTS

Participants' HA-use time averaged 4.8 hr/d (SD 2.4 hr/d) over the 12-week treatment phase. Multilevel regression analyses revealed significant reductions of tinnitus distress scores after 6 and 12 weeks (THI: F(2,156) = 7.80, p < 0.01; TFI: F(2,155) = 8.79, p < 0.01) of treatment, as compared with baseline. After 6 weeks of HA usage, THI scores were decreased by 11.64 points and TFI scores by 12.80 points, on average. There was no further statistically significant reduction in tinnitus distress between 6 and 12 weeks of HA usage (THI: M = 1.75, p = 0.89; TFI: M = -1.58, p = 0.91). Contrary to expectations, none of the included factors predicted these effects. Subjective tinnitus loudness remained unchanged with treatment (M = 1.90; F(1,105) = 0.40, p = 0.53).

CONCLUSIONS

HA usage is associated with reductions in tinnitus-related distress-irrespective of tinnitus attributes, degree of hearing loss, or HA fitting characteristics. Future research designs that include additional predictors, control groups and larger, more heterogeneous samples are needed to further clarify mechanisms of change with hearing amplification in individuals with hearing loss and chronic tinnitus.

A meta-analysis on study and sample characteristics modulating mock earwitness performance

Mock earwitness performance mainly addresses cognitive functions like free recall and recognition of auditory information. Based on primary studies a-priori experimental moderator effects on mock earwitness performance have been hypothesized. Including 46 articles with k = 66 experimental studies, a bare-bones and a random-effects, artefact-corrected meta-analysis have been performed. The results show a substantial ratio of the population effect size and the standard deviation of the population effect size (δ/SDδ) for the a-priori moderators bimodal compared to unimodal stimuli and for gender of listener. These results indicate that bimodal stimuli compared to unimodal stimuli yield substantially better mock earwitness performance. Women outperform men in mock earwitness performance. The fail-safe number demonstrates robust population effects for both a-priori moderators. As a post-hoc moderator, line-ups with target-present revealed substantial δ/SDδ ratios for stimulus length and gender of listener. These results for post-hoc moderators suggest that longer compared to shorter stimuli reveal better mock earwitness performance. The gender of listener effect is in target-present line-ups comparabale to the before mentioned gender of listener effect. G*Power calculations for future primary studies suggest that sample sizes in several primary studies were too small. Single-person earwitness assessments should be substantiated by reality monitoring and disentangled from hearsay evidence (i.e., situations in that individuals have heard information from other persons). The data recommend that best-practice options for earwitnesses in court settings should be derived from meta-analytic results, corresponding to the jurisdictions of the countries and exclusively for results that were substantial (δ/SDδ ratios) and robust (fail-safe number).

Tinnitus: Clinical Insights in Its Pathophysiology-A Perspective

Tinnitus, the perception of sound without a corresponding external sound source, and tinnitus disorder, which is tinnitus with associated suffering, present a multifaceted clinical challenge due to its heterogeneity and its incompletely understood pathophysiology and especially due to the limited therapeutic options. In this narrative review, we give an overview on various clinical aspects of tinnitus including its heterogeneity, contributing factors, comorbidities and therapeutic pathways with a specific emphasis on the implications for its pathophysiology and future research directions. Tinnitus exhibits high perceptual variability between affected individuals (heterogeneity) and within affected individuals (temporal variability). Hearing loss emerges as predominant risk factor and the perceived pitch corresponds to areas of hearing loss, supporting the compensatory response theory. Whereas most people who have tinnitus can live a normal life, in 10-20% tinnitus interferes severely with quality of life. These patients suffer frequently from comorbidities such as anxiety, depression or insomnia, acting as both risk factors and consequences. Accordingly, neuroimaging studies demonstrate shared brain networks between tinnitus and stress-related disorders shedding light on the intricate interplay of mental health and tinnitus. The challenge lies in deciphering causative relationships and shared pathophysiological mechanisms. Stress, external sounds, time of day, head movements, distraction, and sleep quality can impact tinnitus perception. Understanding these factors provides insights into the interplay with autonomic, sensory, motor, and cognitive processes. Counselling and cognitive-behavioural therapy demonstrate efficacy in reducing suffering, supporting the involvement of stress and anxiety-related networks. Hearing improvement, especially through cochlear implants, reduces tinnitus and thus indirectly validates the compensatory nature of tinnitus. Brain stimulation techniques can modulate the suffering of tinnitus, presumably by alteration of stress-related brain networks. Continued research is crucial for unravelling the complexities of tinnitus. Progress in management hinges on decoding diverse manifestations, identifying treatment-responsive subtypes, and advancing targeted therapeutic approaches.

Interventions against hearing loss as an integral component of successful tinnitus therapy

Tinnitus very often develops from acute or chronic hearing loss, mainly inner ear deafness. The frequency of the tinnitus mostly corresponds to the frequency range of the hearing loss and is enhanced by down-regulation of inhibition in the central auditory pathway for these frequencies, in addition to focused attention and enhanced arousal for the disturbing sound. Therefore, interventions to improve hearing such as mid-ear surgery or-more often-electronic devices including hearing aids or cochlear implants (CI) are important for the treatment of tinnitus. In this review, the current German S3 guideline "Chronic tinnitus" and recent literature are discussed.

Should Tinnitus Patients with Subclinical Hearing Impairment Be Offered Hearing Aids? A Comparison of Tinnitus Mitigation Following 3 Months Hearing Aid Use in Individuals with and without Clinical Hearing Impairment

There is a consensus among tinnitus experts to not recommend hearing aids for tinnitus patients with subclinical hearing impairment. However, this notion is arbitrary, as no previous study has compared the treatment effect of hearing aids on tinnitus distress in patients with and without clinical hearing impairment. In this article, we investigate whether tinnitus patients with clinical and subclinical hearing impairment differ in terms of tinnitus mitigation after hearing aid fitting. Twenty-seven tinnitus patients with either clinical (n = 13) or subclinical (n = 14) hearing impairment were fitted with hearing aids. All participants filled out the tinnitus functional index (TFI) before hearing aid fitting and after 3 months of hearing aid use. Clinically meaningful reductions in tinnitus distress (-13 TFI points or more) were seen in both groups, and the difference in tinnitus mitigation between tinnitus patients with clinical (mean TFI reduction = 17.0 points) and subclinical hearing impairment (mean TFI reduction = 16.9 points) was not statistically significant (p = 0.991). Group differences on the suspected confounding factors of age, sex, time since tinnitus debut, tinnitus distress (TFI score) at baseline, and treatment adherence were statistically insignificant. In light of this, we argue that clinical hearing impairment is not required to achieve meaningful tinnitus mitigation with hearing aids, and that hearing aids could be recommended for tinnitus patients with subclinical hearing impairment.

[Interventions against hearing loss are an integral component of successful tinnitus therapy. German version]

Tinnitus very often develops from acute or chronic hearing loss, mainly inner ear deafness. The frequency of the tinnitus mostly corresponds to the frequency range of the hearing loss and is enhanced by down-regulation of inhibition in the central auditory pathway for these frequencies, in addition to focused attention and enhanced arousal for the disturbing sound. Therefore, interventions to improve hearing such as mid-ear surgery or-more often-electronic devices including hearing aids or cochlear implants (CI) are important for the treatment of tinnitus. In this review, the current German S3 guideline "Chronic tinnitus" and recent literature are discussed.

Tinnitus Guidelines and Their Evidence Base

Evidence-based medicine (EBM) is generally accepted as the gold standard for high-quality medicine and, thus, for managing patients with tinnitus. EBM integrates the best available scientific information with clinical experience and patient values to guide decision-making about clinical management. To help health care providers and clinicians, the available evidence is commonly translated into medical or clinical guidelines based on a consensus. These involve a systematic review of the literature and meta-analytic aggregation of research findings followed by the formulation of clinical recommendations. However, this approach also has limitations, which include a lack of consideration of individual patient characteristics, the susceptibility of guideline recommendations to material and immaterial conflicts of interest of guideline authors and long latencies till new knowledge is implemented in guidelines. A further important aspect in interpreting the existing literature is that the absence of evidence is not evidence of absence. These circumstances could result in the decoupling of recommendations and their supporting evidence, which becomes evident when guidelines from different countries differ in their recommendations. This opinion paper will discuss how these weaknesses can be addressed in tinnitus.