Dual-site transcranial direct current stimulation to treat tinnitus: a randomized controlled trial.

Transcranial direct current stimulation (tDCS) has been proposed as a potential intervention for subjective tinnitus, but supporting evidence remains limited. We aimed to investigate the effect of anodal high-definition tDCS of the left temporal area and right dorsolateral prefrontal cortex on tinnitus severity. This double-blind randomized controlled trial included 77 patients (age range 18-79, 43 male) with chronic subjective tinnitus as their primary complaint. Thirty-eight subjects received six consecutive sessions of dual-site sequential high-definition-tDCS with electrodes positioned over the left temporal area and right dorsolateral prefrontal cortex. Both areas were stimulated for 15 min per session, with total stimulation time amounting to 30 min. Thirty-nine subjects received sham stimulation. The primary outcome measure was the change in tinnitus severity, as evaluated by the Tinnitus Functional Index, from baseline to a follow-up visit at 8 ± 2 weeks after treatment completion. Secondary outcomes included changes in perceived tinnitus loudness, as measured with a visual analogue scale and a tinnitus matching procedure, as well as scores on the Hospital Anxiety and Depression Scale, and the Hyperacusis Questionnaire. No differences in Tinnitus Functional Index change scores were identified between the active treatment and sham control groups (linear regression: P = 0.86). The Tinnitus Functional Index scores decreased significantly over time in both groups (P = 0.0012), indicating the presence of a considerable placebo effect. These change scores were significantly influenced by sex (linear regression: P = 0.037) and baseline symptoms of anxiety (linear regression: P = 0.049) in both groups. In general, Tinnitus Functional Index scores decreased more profoundly in males and in subjects with a higher degree of anxiety at baseline. None of the included secondary measures differed significantly between experimental arms. Our results suggest that dual-site sequential high-definition-tDCS of the left temporal area and right dorsolateral prefrontal cortex does not alleviate tinnitus severity. Interestingly, in our study population, fluctuations in tinnitus severity were influenced by gender and concurrent mental condition. It is therefore important to take these factors into account when conducting or planning randomized controlled trials in tinnitus populations.

Pilot study on the role of somatic modulation in hyperacusis.

BACKGROUND: Hyperacusis is a reduced tolerance to sounds that often co-occurs with tinnitus. Both symptoms have convergent as well as divergent characteristics. Somatic modulation, changes in pitch or loudness during certain movements, is common in patients with a primary complaint of tinnitus. However, thus far, this is not documented in patients with hyperacusis. OBJECTIVES: This study aimed to examine the influence of somatic manoeuvres on the perception of external sounds in patients with a primary complaint of hyperacusis. METHODOLOGY: In this prospective cross-sectional pilot study, 18 patients with a primary complaint of hyperacusis were recruited at the Tinnitus Treatment and Research Center Antwerp (TINTRA). While patients listened to a 1 kHz broadband noise of 30 dB sensation level, six neck manoeuvres (flexion, extension, lateroflexion left/right, traction and compression), three jaw manoeuvres (protrusion, laterotrusion left/right) and one placebo manoeuvre (hand on head) were performed. The primary outcome measure was the change in the perception of the presented sound in terms of loudness and intrusiveness between baseline and each modulation measured by a visual analogue scale (VAS). RESULTS: No overall significant changes were found; however, individual results indicated that five patients presented a clinically relevant change of more than three points out of ten on VAS in terms of hyperacusis after at least one of the executed somatic manoeuvres. CONCLUSIONS: This pilot study did not demonstrate an overall significant change in hyperacusis after somatic manoeuvres but does not rule out the possibility of somatic modulation in some hyperacusis patients. TRIAL REGISTRATION: The protocol of this prospective cross-sectional pilot study was registered on clinicaltrials.gov with registration number NCT04693819.

Contralateral hearing aid use in adult cochlear implant recipients: retrospective analysis of auditory outcomes.

OBJECTIVE: To investigate retrospectively the frequency of usage of bimodal stimulation among cochlear implant (CI) users, as well its clinical benefit relative to unilateral use. DESIGN: All subjects had been monitored with the clinical Minimal Outcome Measurements test battery. STUDY SAMPLES: 103 adults with bilateral postlingual profound sensorineural hearing loss and unilateral CI use were extracted from the local database. These were divided into two groups: those who only used a CI and those who used bimodal stimulation. RESULTS: The preoperative contralateral residual hearing in the bimodal group was significantly better than that of the CI-only group. In both groups, speech perception in quiet and in noise improved after CI, with no significant difference between postoperative unimodal conditions. For the bimodal group, an additional significant improvement was found for the bimodal condition compared to the unimodal. CONCLUSION: Given the observed auditory benefit of bimodal stimulation in comparison to unimodal stimulation and given the finding that degree of residual hearing is not correlated with bimodal benefits, it is recommended to encourage CI recipients to continue contralateral HA use after CI. As a result of expanding CI criteria worldwide, the population of bimodal users is expected to grow in the near future.

Long-term effects of a single psycho-educational session in chronic tinnitus patients.

PURPOSE: To evaluate the effects of a single psycho-educational session on tinnitus burden in chronic tinnitus patients. The session is organized at a tertiary referral center for otologic disorders at the University Hospital Antwerp as a group session (maximum of 10-15 patients a time) lasting for approximately 3-4 h. The session focusses on different aspects of tinnitus. METHODS: The current manuscript reports on 96 patients who completed the Tinnitus Functional Index (TFI), Visual Analogue Scale for mean loudness (VAS), Hyperacusis Questionnaire (HQ), and the Hospital Anxiety and Depression Scale (HADS) prior to treatment and at 6-month follow-up. The TFI was chosen as the primary outcome. Paired-samples T tests were performed to evaluate therapy effect at 6-month follow-up. In addition, a logistic regression model revealed baseline TFI/VAS scores and duration of tinnitus as contributing factors to a significant decrease of the TFI. RESULTS: The TFI total score showed a significant decrease (p < 0.001) at the 6-month follow-up time point. At follow-up, 75% of patients reported their tinnitus to be under control not requiring any additional treatment. The logistic regression model showed that patients with higher baseline TFI scores, lower baseline mean VAS loudness ratings, and shorter tinnitus duration were more likely to show clinically significant improvement on the TFI scale. CONCLUSIONS: Tinnitus Retraining Therapy or Cognitive Behavioural Therapy are effective, though very time-consuming and expensive treatments. A single psycho-educational group session was shown to be highly effective in decreasing the tinnitus burden, which increases feasibility and cost-effectiveness. TRIAL REGISTRATION: Not applicable as this is a retrospective reporting of tinnitus outcome in the daily clinical practice, not a clinical trial.

Effectiveness of bimodal auditory and electrical stimulation in patients with tinnitus: A feasibility study.

Background: Tinnitus is a common symptom, affecting about 10-15% of the adult population. When input from the somatosensory system can influence and/or elicit tinnitus, this type of subjective tinnitus is called somatosensory tinnitus. Recently, a new type of bimodal neurostimulation treatment has shown promising results for a specific subgroup within the somatosensory tinnitus population. It is, however, not clear if this bimodal stimulation is also effective in patients with other types of subjective tinnitus. Aim: The aim of this study was to evaluate the feasibility and efficacy of non-invasive bimodal auditory-somatosensory stimulation in reducing tinnitus severity among a general population of people with subjective tinnitus. Methods: Chronic subjective tinnitus patients were recruited from the ENT department of the Antwerp University Hospital. Somatosensory stimulation was delivered by Transcutaneous Electrical Nerve Stimulation (TENS), and it was combined with auditory stimulation via headphones. The therapy comprised six sessions of thirty minutes twice a week for a period of 3 consecutive weeks. Follow up measurements were scheduled 9-12 weeks after the last treatment session. The change of the Tinnitus Functional Index (TFI) score, a questionnaire evaluating tinnitus burden and effects on the quality of life, was the primary outcome measure. Results: Twenty-nine patients were enrolled in the study. A linear mixed-effects model was used to analyze the efficacy of bimodal treatment. The results of this analysis showed a statistically significant decrease (by 6, 9 points) in average TFI score at the follow up visit when compared to baseline. The ability to modulate tinnitus did not have an influence on the treatment results. Conclusion: Our study showed that bimodal stimulation is a feasible and safe method of tinnitus treatment. The method might be an effective treatment for some participants with tinnitus, especially those who have accompanying neck/temporomandibular problems, although, the evidence from this trial is quite weak. Additional research is needed toward establishing the optimal treatment protocol, as well as selecting the most appropriate inclusion criteria.

Cost-effectiveness of a smartphone Application for Tinnitus Treatment (the CATT trial): a study protocol of a randomised controlled trial.

BACKGROUND: Tinnitus is a highly prevalent symptom, affecting 10-15% of the adult population. Tinnitus influenced by alterations in somatosensory afference from the neck or jaw is referred to as somatic tinnitus (ST). ST is known to respond positively to physiotherapy treatment; however, it is challenging to motivate patients to systematically perform home exercises correctly, and the necessary tinnitus counselling is often lacking. The aim of this study is twofold, namely to investigate both the effectiveness and cost-effectiveness of a blended physiotherapy program for ST, including a smartphone application designed to increase exercise therapy compliance and provide tinnitus counselling. METHODS: This study is designed as a single-blind two-arm 1:1 randomised controlled trial (RCT). Adult patients diagnosed with ST, without psychiatric comorbidities and with experience in using a smartphone, will be recruited at the Ear Nose Throat (ENT) department of the Antwerp University Hospital (UZA). Patients will be randomised into two groups. The experimental group will receive the blended physiotherapy program comprising six in-clinic physiotherapy sessions over a period of 12 weeks (1x/2 weeks) and an exercise and counselling program provided by the smartphone application. The control group will receive the standard care program comprising twelve weekly in-clinic physiotherapy sessions. Each physiotherapy session has a duration of 30 min. The primary outcome measure is the change in Tinnitus Functional Index (TFI) score. Additionally, a cost-effectiveness analysis will be performed from a societal perspective considering both direct and indirect costs. There will be follow-up assessments at one and 3 months after the final treatment session. DISCUSSION: Our study is the first to combine both tinnitus counselling and neck/jaw treatment provided by a digital application in a blended physiotherapy program. This, in order to empower ST patients to improve and better manage their own health and, possibly, reduce economic costs by alleviating the tinnitus burden that ST patients experience. The strengths of the planned RCT are the high-quality methodological design, the large sample size and the expertise of the involved multidisciplinary research team. TRIAL REGISTRATION: Clinicaltrials.gov NCT05245318 . Registered on 26 January 2022.

Cortical auditory evoked potentials, brain signal variability and cognition as biomarkers to detect the presence of chronic tinnitus.

The current limited understanding of tinnitus neurophysiology is one of the major obstacles in developing effective treatments for chronic tinnitus. As such, there is an urgent need for knowledge on underlying neural and/or neurobehavioral correlates that might function as potential biomarkers for tinnitus. We aimed to develop a model for the detection of tinnitus cases based on such potential biomarkers. In a first step, data from twenty patients suffering from chronic tinnitus, but no concurrent hearing loss or psychological complaints, were compared to data from twenty matched controls. Cortical auditory evoked potentials (CAEP) were elicited using a standard oddball paradigm. Source estimation and brain signal variability were analyzed to investigate putative differences between tinnitus patients and controls. Other examinations included standard audiometry, speech understanding in quiet and noisy conditions, and cognitive testing using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The P300 component, a response to unexpected but relevant stimuli, was significantly reduced in the tinnitus group. Source estimation revealed that the response of tinnitus patients was characterized by a decreased activity in temporal cortex, parahippocampus and insula. Brain signal variability on fine time scales was significantly higher in the tinnitus group, suggesting that tinnitus patients rely more strongly on local information processing. Furthermore, tinnitus was associated with a decreased cognitive performance, especially on tasks measuring delayed memory. In a second step, a logistic regression model was constructed based on CAEP activity, brain signal variability and RBANS scores. This model performed significantly above chance level when detecting tinnitus cases in an unseen dataset (accuracy of 75%, area under the ROC curve of 0.86). The successful classification between tinnitus cases and controls demonstrates the potential value of the proposed combination of biomarkers. Moreover, the identified associations between tinnitus, auditory evoked activity and cognitive performance point towards a significant contribution of top-down information processing in the perception of tinnitus.

Systematic review and meta-analysis of late auditory evoked potentials as a candidate biomarker in the assessment of tinnitus.

Subjective tinnitus, the perception of sound in the absence of any sound source, is routinely assessed using questionnaires. The subjective nature of these tools hampers objective evaluation of tinnitus presence, severity and treatment effects. Late auditory evoked potentials (LAEPs) might be considered as a potential biomarker for assessing tinnitus complaints. Using a multivariate meta-analytic model including data from twenty-one studies, we determined the LAEP components differing systematically between tinnitus patients and controls. Results from this model indicate that amplitude of the P300 component is lower in tinnitus patients (standardized mean difference (SMD) = -0.83, p < 0.01), while latency of this component is abnormally prolonged in this population (SMD = 0.97, p < 0.01). No other investigated LAEP components were found to differ between tinnitus and non-tinnitus subjects. Additional sensitivity analyses regarding differences in experimental conditions confirmed the robustness of these results. Differences in age and hearing levels between the two experimental groups might have a considerable impact on LAEP outcomes and should be carefully considered in future studies. Although we established consistent differences in the P300 component between tinnitus patients and controls, we could not identify any evidence that this component might covary with tinnitus severity. We conclude that out of several commonly assessed LAEP components, only the P300 can be considered as a potential biomarker for subjective tinnitus, although more research is needed to determine its relationship with subjective tinnitus measures. Future trials investigating experimental tinnitus therapies should consider including P300 measurements in the evaluation of treatment effect.