Associations between intake of dietary flavonoids and the 10-year incidence of tinnitus in older adults.

PURPOSE: Dietary flavonoids are bioactive compounds that have been widely investigated for their associations with vascular health outcomes. As the development of tinnitus has been linked to vascular pathways, dietary flavonoids may have role in the prevention of tinnitus symptoms. This study reports the associations between the intakes of major classes of dietary flavonoids and 10-year incidence of tinnitus. METHODS: Of the 1753 participants (aged ≥ 50 years) from the Blue Mountains Hearing Study with complete baseline data on tinnitus symptoms and dietary intakes, 536 (31%) cases of tinnitus were identified and excluded from further analysis. Dietary data was collected using a semi-quantitative food frequency questionnaire and intakes of the five major classes of flavonoids were determined using U.S. Department of Agriculture flavonoid databases. Presence of prolonged tinnitus was assessed by a positive response to a single question administered by an audiologist. RESULTS: Of the remaining 1217 participants without tinnitus at baseline, 222 (18%) incident cases of tinnitus were identified over 10 years. After age-sex adjustment, participants in the third versus first quartile of proanthocyanidin intake were significantly less likely to develop incident tinnitus by 36% (HR = 0.64; 95% CI 0.43-0.96, Ptrend = 0.04). Following multivariable adjustment, this protective trend was non-significant (HR = 0.60; 95% CI 0.39-0.92; Ptrend = 0.06). Similarly, a non-significant protective trend was observed when comparing the fourth versus first quartile of intake of all flavonoids (OR = 0.61; 95% CI 0.39-0.96). No other associations were observed. CONCLUSION: Our findings do not support the hypothesis that dietary flavonoids are protective against the development of tinnitus over 10 years. The weak significant association observed between proanthocyanidin and incident tinnitus may be a chance finding as there was no significant trend following multivariate adjustments and, therefore, requires further studies to investigate these associations.

The Association between Dietary Intakes of Vitamins and Minerals with Tinnitus.

BACKGROUND: Tinnitus is the phantom perception of sound in the ears or head which may result from inflammation of the auditory pathway. A healthy diet consisting of a range of vitamins and minerals may be protective against tinnitus. This study aims to determine the association between intakes of dietary vitamins and minerals and the prevalence and incidence of tinnitus over 10 years. METHODS: In this longitudinal cohort study of 2947 participants (aged ≥ 50 years), 935 (32%) cases of tinnitus were identified and included in prevalence analyses. The remaining 2012 participants were followed to establish 10-year incidence of tinnitus. A validated semi-quantitative food frequency questionnaire was used to determine intakes of dietary vitamins and minerals. RESULTS: No significant associations with tinnitus prevalence were found. However, iron and zinc were significantly associated with incident tinnitus. There was a 44% (multivariate-adjusted HR: 1.44, 95% CI: 1.07-1.93) increased risk of developing incident tinnitus over 10 years with lower zinc intakes and a 35% increased risk with lower iron intakes (multivariate-adjusted HR: 1.35, 95% CI: 1.00-1.80). CONCLUSION: Higher intakes of zinc and iron were significantly associated with lower tinnitus risk. Due to a lack of comparable high-quality data, future research studies should include robust study designs.

Neuromodulation Treatments Targeting Pathological Synchrony for Tinnitus in Adults: A Systematic Review.

(1) Background: Tinnitus involves the conscious awareness of a tonal or composite noise for which there is no identifiable corresponding external acoustic source. For many people, tinnitus is a disorder associated with symptoms of emotional distress, cognitive dysfunction, autonomic arousal, behavioural changes, and functional disability. Many symptoms can be addressed effectively using education or cognitive behavioural therapy. However, there is no treatment that effectively reduces or alters tinnitus-related neurophysiological activity and thus the tinnitus percept. In this systematic review, we evaluated the effectiveness of neuromodulation therapies for tinnitus that explicitly target pathological synchronous neural activity. (2) Methods: Multiple databases were searched for randomised controlled trials of neuromodulation interventions for tinnitus in adults, with 24 trials included. The risk of bias was assessed, and where appropriate, meta-analyses were performed. (3) Results: Few trials used acoustic, vagal nerve, or transcranial alternating current stimulation, or bimodal stimulation techniques, with limited evidence of neuromodulation or clinical effectiveness. Multiple trials of transcranial direct current stimulation (tDCS) were identified, and a synthesis demonstrated a significant improvement in tinnitus symptom severity in favour of tDCS versus control, although heterogeneity was high. (4) Discussion: Neuromodulation for tinnitus is an emerging but promising field. Electrical stimulation techniques are particularly interesting, given recent advances in current flow modelling that can be applied to future studies.

Dietary Flavonoid Intake and Chronic Sensory Conditions: A Scoping Review.

Dietary flavonoids have antioxidant, anti-inflammatory, and vascular health benefits, which align with the proposed pathophysiology of age-related eye conditions and hearing problems (hearing loss and tinnitus). This scoping review is based on Arksey and O'Malley's six-stage framework and aims to summarise current evidence on the association between the dietary flavonoid intake and chronic sensory conditions in adults, and to identify the research gaps in this area. Eligible studies were identified by searching MEDLINE, EMBASE PsycINFO via the OVID platform, and Google Scholar, as well as manually searching the reference lists of the eligible articles. The inclusion criteria included: articles with full-text access, written in the English language, and focused on chronic sensory conditions and dietary flavonoid intake in an adult population. Studies focused on flavonoid supplements were excluded. Ten studies were included in this review. The evidence suggests that the flavonoid subclass, flavonols, are protective against eye conditions, including age-related macular degeneration, cataract, and glaucoma. There is insufficient evidence to support an association with hearing loss or tinnitus. Overall, dietary flavonol intake appears to be protective against some chronic eye conditions. However, for most eye and hearing-related conditions, only one study was identified. Thus, there is a need for more recent high-quality research to be conducted to confirm any significant associations.

Dietary Fibre Intake and the 10-Year Incidence of Tinnitus in Older Adults.

Tinnitus is the phantom perception of sound in the ears or head that increases in prevalence as age increases. With strong evidence supporting the benefits of dietary fibre for vascular health and hearing loss, intake of dietary fibre may also have a role in the prevention of tinnitus symptoms. This longitudinal study aims to determine the association between the intake of dietary fibre and other carbohydrate nutrition variables including glycaemic index (GI), glycaemic load (GL) and total carbohydrate intakes, and incident tinnitus over 10 years. Of the 1730 participants (aged ≥50 years) from the Blue Mountains Hearing Study with complete baseline data on tinnitus symptoms and carbohydrate intakes, 536 (31%) cases of tinnitus were identified and excluded from further incidence analysis. Dietary data were collected using a validated semi-quantitative food frequency questionnaire to determine intakes of total dietary fibre and fibre contributions from cereals, vegetables, and fruit. A purpose-built database based on Australian GI values was used to calculate mean GI. Lower versus higher intakes of fruit fibre (≤3.6 g/day vs. >3.6 g/day) and cereal fibre (≤4.2 g/day vs. >4.2 g/day) were significantly associated with a 65% (HR = 1.65; 95% CI: 1.15-2.36) and 54% (HR = 1.54; 95% CI: 1.07-2.22) increased risk of developing tinnitus over 10 years, respectively. Associations between intake of other carbohydrate nutrients and incident tinnitus were mostly non-significant. In summary, our study showed modest associations between intake of dietary fibre and incident tinnitus. The protective effects of fibre, particularly insoluble fibre, could underlie observed associations by reducing the risk of tinnitus via vascular risk factors such as cardiovascular disease. Further longitudinal studies evaluating different types and sources of fibre and tinnitus risk are needed to confirm our study findings.

Psychometric Validity, Reliability, and Responsiveness of the Tinnitus Functional Index.

BACKGROUND: The effects of treatments on tinnitus have been difficult to quantify. The Tinnitus Functional Index (TFI) has been proposed as a standard questionnaire for measurement of tinnitus treatment outcomes. For a questionnaire to achieve wide acceptance, its psychometric properties need to be confirmed in different populations. OBJECTIVE: To determine if the TFI is a reliable and valid measure of tinnitus, and if its psychometric properties are suitable for use as an outcome measure. RESEARCH DESIGN: A psychometric evaluation of the TFI from secondary data obtained from a cross-sectional clinic survey and a clinical trial undertaken in New Zealand. STUDY SAMPLE: Confirmatory factor analysis and evaluation of internal consistency reliability were undertaken on a sample of 318 patients with the primary complaint of tinnitus. In a separate sample of 40 research volunteers, test-retest reliability, convergent and divergent validity were evaluated. Both samples consisted of predominantly older Caucasian male patients with tinnitus. RESULTS: The internal structure of the original US TFI was confirmed. The Cronbach's Alpha and Intraclass correlation coefficients were >0.7 for the TFI overall and each of its subscales, indicating high internal consistency and test-retest reliability. Strong Pearson correlations with the Tinnitus Handicap Questionnaire and tinnitus numerical rating scales indicated excellent convergent validity, and a moderate correlation with the Hearing Handicap Inventory, indicated moderate divergent validity. Evaluation of the clinical trial showed good test-retest reliability and agreement between no-treatment baselines with a smallest detectable change of 4.8 points. CONCLUSIONS: The TFI is a reliable and valid measure of tinnitus severity in the population tested and is responsive to treatment-related change. Further research as to the TFI's responsiveness to treatment is needed across different populations.

Clinical Interventions for Hyperacusis in Adults: A Scoping Review to Assess the Current Position and Determine Priorities for Research.

BACKGROUND: There is no universally accepted definition for hyperacusis, but in general it is characterised by decreased sound tolerance to ordinary environmental sounds. Despite hyperacusis being prevalent and having significant clinical implications, much remains unknown about current management strategies. PURPOSE: To establish the current position of research on hyperacusis and identify research gaps to direct future research. DESIGN AND SAMPLE: Using an established methodological framework, electronic and manual searches of databases and journals identified 43 records that met our inclusion criteria. Incorporating content and thematic analysis approaches, the definitions of hyperacusis, management strategies, and outcome measures were catalogued. RESULTS: Only 67% of the studies provided a definition of hyperacusis, such as "reduced tolerance" or "oversensitivity to sound." Assessments and outcome measures included Loudness Discomfort Levels, the Hyperacusis Questionnaire, and Tinnitus Retraining Therapy (TRT) interview. Management strategies reported were Cognitive Behavioural Therapy, TRT, devices, pharmacological therapy, and surgery. CONCLUSIONS: Management strategies were typically evaluated in patients reporting hyperacusis as a secondary complaint or as part of a symptom set. As such the outcomes reported only provided an indication of their effectiveness for hyperacusis. Randomised Controlled Trials are needed to evaluate the effectiveness of management strategies for patients experiencing hyperacusis.

Comparison of the Long-Term Effect of Positioning the Cathode in tDCS in Tinnitus Patients.

Objective: Transcranial direct current stimulation (tDCS) is one of the methods described in the literature to decrease the perceived loudness and distress caused by tinnitus. However, the main effect is not clear and the number of responders to the treatment is variable. The objective of the present study was to investigate the effect of the placement of the cathode on the outcome measurements. Methods: Patients considered for the trial were chronic non-pulsatile tinnitus patients with complaints for more than 3 months and a Tinnitus Functional Index (TFI) score that exceeded 25. The anode was placed on the right dorsolateral prefrontal cortex (DLPFC). In the first group-"bifrontal"-the cathode was placed on the left DLPFC, while in the second group-"shoulder"-the cathode was placed on the shoulder. Each patient received two sessions of tDCS weekly and eight sessions in total. Evaluations took place on the first visit for an ENT consultation, at the start of therapy, after eight sessions of tDCS and at the follow-up visit, which took place 84 days after the start of the therapy. Subjective outcome measures such as TFI, Visual Analog Scales (VAS) for loudness and percentage of consciousness of tinnitus were administered in every patient. Results: There was no difference in the results for tinnitus loudness and the distress experienced between the placement of the cathode on the left DLPFC or on the shoulder. In addition, no statistically significant overall effect was found between the four test points. However, up to 39.1% of the patients experienced a decrease in loudness, measured by the VAS for loudness. Moreover, 72% of those in the bifrontal group, but only 46.2% of those in the shoulder group reported some improvement in distress. Conclusion: While some improvement was noted, this was not statistically significant. Both electrode placements stimulated the right side of the hippocampus, which could be responsible for the effect found in both groups. Further research should rule out the placebo effect and investigate alternative electrode positions.