Sequential dual-site High-Definition transcranial Direct Current Stimulation (HD-tDCS) treatment in chronic subjective tinnitus: study protocol of a double-blind, randomized, placebo-controlled trial

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.

Random Forest Classification to Predict Response to High-Definition Transcranial Direct Current Stimulation for Tinnitus Relief: A Preliminary Feasibility Study

OBJECTIVES

Transcranial direct current stimulation (tDCS) of the right dorsolateral prefrontal cortex has been hypothesized to reduce tinnitus severity by modifying cortical activity in brain regions associated with the perception of tinnitus. However, individual response to tDCS has proven to be variable. We investigated the feasibility of using random forest classification to predict the response to high-definition (HD) tDCS for tinnitus relief.

DESIGN

A retrospective analysis was performed on a dataset consisting of 99 patients with subjective tinnitus receiving six consecutive sessions of HD-tDCS at the Antwerp University Hospital. A baseline assessment consisted of pure-tone audiometry and a set of questionnaires including the Tinnitus Functional Index (TFI), Hospital Anxiety and Depression Scale, and Edinburgh Handedness Inventory. Random forest classification was applied to predict, based on baseline questionnaire scores and hearing levels, whether each individual responded positively to the treatment (defined as a decrease of at least 13 points on the TFI). Further testing of the model was performed on an independent cohort of 32 patients obtained from the tinnitus center at the University of Regensburg.

RESULTS

Twenty-four participants responded positively to the HD-tDCS treatment. The random forest classifier predicted treatment response with an accuracy of 85.71% (100% sensitivity, 81.48% specificity), significantly outperforming a more traditional logistic regression approach. Performance of the classifier on an independent cohort was slightly but not significantly above chance level (71.88% accuracy, 66.67% sensitivity, 73.08% specificity). Feature importance analyses revealed that baseline tinnitus severity, co-occurrence of depressive symptoms and handedness were the most important predictors of treatment response. Baseline TFI scores were significantly higher in responders than in nonresponders.

CONCLUSIONS

The proposed random forest classifier predicted treatment response with a high accuracy, significantly outperforming a more traditional statistical approach. Machine learning methods to predict treatment response might ultimately be used in a clinical setting to guide targeted treatment recommendations for individual tinnitus patients.

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.

Hyperacusis: demographic, audiological, and clinical characteristics of patients at the ENT department

PURPOSE

To document whether patients with and without hyperacusis differ from each other on demographic, audiological, and clinical characteristics.

METHODS

Based on the Hyperacusis Questionnaire's (HQ) cut-off (HQ > 28), a total of 2301 participants were divided into patients with and without hyperacusis. Demographic data, scores on self-reported questionnaires [Tinnitus Functional Index (TFI), Visual Analogue Scale of tinnitus loudness (VAS_loudness), Hospital Anxiety Depression Scale (HADS)], and audiological parameters were retrospectively analysed to determine differential factors between the two groups.

RESULTS

In total, 10.9% of the patients was classified as hyperacusis patients (n = 251). They reported a significant, higher tinnitus severity (mean difference of 19 points on TFI) and mental distress (mean difference of 4 points on the HADS subscales) (p < 0.001) than patients without hyperacusis. Moreover, this group consisted of more women (45% % in hyperacusis group vs. 35% in non-hyperacusis group) and women scored significantly higher on the HQ (p < 0.001) and TFI (p < 0.01).

CONCLUSION

Patients with hyperacusis have distinctive characteristics. The presence of hyperacusis in combination with tinnitus can indicate a higher need for psychoeducation. Patients that present themselves with hyperacusis without tinnitus complaints remain a minority, yet might be underdiagnosed. Hence, future studies should disentangle tinnitus from hyperacusis. In clinical practice, greater efforts are required to increase knowledge about hyperacusis as a primary or secondary complaint and to provide individualized treatment for these patients.

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.