Randomized controlled trial of a smartphone-based cognitive behavioral therapy for chronic tinnitus.

Tinnitus, the phantom perception of sounds, generates distress and anxiety in those affected. Cognitive behavioral treatment approaches reproducibly help patients in managing chronic tinnitus. This study systematically evaluated the usefulness of a tinnitus app (with areas of attention and relaxation, mindfulness, acceptance, self-efficacy), which is prescribed for a total of nine months. One hundred eighty-seven participants with chronic tinnitus were equally randomized to an intervention arm that used a smartphone-based intervention -marketed as Kalmeda Tinnitus app-. and a control arm with delayed onset of treatment by 3 months. The first 3 months of a 9-months prescribed intervention have been analyzed as primary outcome. The Tinnitus Questionnaire (TQ) was used as primary endpoint to determine the reduction of tinnitus distress. Following intervention, there was a statistically significant and clinically relevant reduction of the TQ sum score in the intervention group compared to the control group (p<0.001, Cohen's d effect size = 1.1). The secondary parameters, Patient Health Questionnaire-9 (PHQ9) and Perceived-Stress-Questionnaire (PSQ20) scores improved significantly in the intervention group whereas the Self Efficacy-Optimism-Pessimism short form (SWOP-K9) scores remained unchanged in both groups. Patients reported no treatment-related side effects. Taken together, use of this Tinnitus app lead to a significant decrease in tinnitus distress and a clinically relevant effect in the patients´ self-reported everyday management.

Tinnitus at the Junction of Traditional Medicine and Modern Technology.

The WHO estimated that 430 million people worldwide suffer from moderate-to-severe hearing loss [...].

Auricular Acupressure Combined with Self-Help Intervention for Treating Chronic Tinnitus: A Longitudinal Observational Study.

Tinnitus is a phantom sound perception in the ears or head and can arise from many different medical disorders. Currently, there is no standard treatment for tinnitus that reliably reduces tinnitus. Individual patients reported that acupressure at various points around the ear can help to reduce tinnitus, which was investigated here. With this longitudinal observational study, we report a systematic evaluation of auricular acupressure on 39 tinnitus sufferers, combined with a self-help smartphone app. The participants were asked to report on tinnitus, stress, mood, neck, and jaw muscle tensions twice a day using an ecological momentary assessment study design for six weeks. On average, 123.6 questionnaires per person were provided and used for statistical analysis. The treatment responses of the participants were heterogeneous. On average, we observed significant negative trends for tinnitus loudness (Cohen's d effect size: -0.861), tinnitus distress (d = -0.478), stress (d = -0.675), and tensions in the neck muscles (d = -0.356). Comparison with a matched control group revealed significant improvements for tinnitus loudness (p = 0.027) and self-reported stress level (p = 0.003). The positive results of the observational study motivate further research including a randomized clinical trial and long-term assessment of the clinical improvement.

Gender differentiates effects of acoustic stimulation in patients with tinnitus.

Gender constitutes a major factor to consider when tailoring subtype-based therapies for tinnitus. Previous reports showed important differences between men and women concerning basic perceptual tinnitus characteristics (i.e., laterality, frequency, tinnitus loudness) as well as psychological reactions linked to this condition. Therapeutic approaches based on acoustic stimulation involve processes beyond a pure masking effect and consist of sound presentation temporarily altering or alleviating tinnitus perception via residual and/or lateral inhibition mechanisms. Presented stimuli may include pure tones, noise, and music adjusted to or modulated to filter out tinnitus pitch and therefore trigger reparative functional and structural changes in the auditory system. Furthermore, recent findings suggest that in tonal tinnitus, the presentation of pitch-adjusted sounds which were altered by a 10Hz modulation of amplitude was more efficient than unmodulated stimulation. In this paper, we investigate sex differences in the outcome of different variants of acoustic stimulation, looking for factors revealing predictive value in the efficiency of tinnitus relief.

Prolonged tinnitus suppression after short-term acoustic stimulation.

BACKGROUND: Tinnitus suppression following acoustic stimulation is a well-known phenomenon also termed residual inhibition (RI). Some individuals may experience prolonged RI (PRI), which can last for several hours or even days, after a single short-term acoustic stimulation. Exact mechanisms of this phenomenon are unknown and current evidence anecdotal. OBJECTIVES: The aim of our report is to collect, present, and discuss cases of PRI from our studies on acoustic stimulation in tinnitus with the aim to better understand this phenomenon as well as its implications for individualized treatments. METHODS: We pooled cases of PRI from four of our studies with a total sample size of n = 130. The criterion was set on a PRI duration which is at least sustained twice as long as the acoustic stimulation duration. RESULTS: We report a total number of about 5% of all participants experiencing some form of PRI, with rates of 3%-7% across the individual studies. PRI lasted from 20 min up to several days and was induced by the first stimulus in four out of six cases. Four out of six individuals experiencing PRI were female and PRI mostly occurred when acoustic stimuli were matched to the frequency or type of the tinnitus. CONCLUSION: PTS seems to be elicitable in a small subset of tinnitus patients which could inform future individualized treatment options. Future studies should investigate if and how identified factors like stimulus type, position, sex, and chronification grade uphold experimental scrutiny. We propose that the set of methods is furthermore extended with neurophysiology in particular.

Towards a unification of treatments and interventions for tinnitus patients: The EU research and innovation action UNITI.

Tinnitus is the perception of a phantom sound and the patient's reaction to it. Although much progress has been made, tinnitus remains a scientific and clinical enigma of high prevalence and high economic burden, with an estimated prevalence of 10%-20% among the adult population. The EU is funding a new collaborative project entitled "Unification of Treatments and Interventions for Tinnitus Patients" (UNITI, grant no. 848261) under its Horizon 2020 framework. The main goal of the UNITI project is to set the ground for a predictive computational model based on existing and longitudinal data attempting to address the question of which treatment or combination of treatments is optimal for a specific patient group based on certain parameters. Clinical, epidemiological, genetic and audiological data, including signals reflecting ear-brain communication, as well as patients' medical history, will be analyzed making use of existing databases. Predictive factors for different patient groups will be extracted and their prognostic relevance validated through a Randomized Clinical Trial (RCT) in which different patient groups will undergo a combination of tinnitus therapies targeting both auditory and central nervous systems. From a scientific point of view, the UNITI project can be summarized into the following research goals: (1) Analysis of existing data: Results of existing clinical studies will be analyzed to identify subgroups of patients with specific treatment responses and to identify systematic differences between the patient groups at the participating clinical centers. (2) Genetic and blood biomarker analysis: High throughput Whole Exome Sequencing (WES) will be performed in well-characterized chronic tinnitus cases, together with Proximity Extension Assays (PEA) for the identification of blood biomarkers for tinnitus. (3) RCT: A total of 500 patients will be recruited at five clinical centers across Europe comparing single treatments against combinational treatments. The four main treatments are Cognitive Behavioral Therapy (CBT), hearing aids, sound stimulation, and structured counseling. The consortium will also make use of e/m-health applications for the treatment and assessment of tinnitus. (4) Decision Support System: An innovative Decision Support System will be implemented, integrating all available parameters (epidemiological, clinical, audiometry, genetics, socioeconomic and medical history) to suggest specific examinations and the optimal intervention strategy based on the collected data. (5) Financial estimation analysis: A cost-effectiveness analysis for the respective interventions will be calculated to investigate the economic effects of the interventions based on quality-adjusted life years. In this paper, we will present the UNITI project, the scientific questions that it aims to address, the research consortium, and the organizational structure.

Comparison of Amplitude Modulated Sounds and Pure Tones at the Tinnitus Frequency: Residual Tinnitus Suppression and Stimulus Evaluation.

Recent studies have compared tinnitus suppression, or residual inhibition, between amplitude- and frequency-modulated (AM) sounds and noises or pure tones (PT). Results are indicative, yet inconclusive, of stronger tinnitus suppression of modulated sounds especially near the tinnitus frequency. Systematic comparison of AM sounds at the tinnitus frequency has not yet been studied in depth. The current study therefore aims at further advancing this line of research by contrasting tinnitus suppression profiles of AM and PT sounds at the matched tinnitus frequency (i.e., 10 and 40 Hz AM vs. PT). Participants with chronic, tonal tinnitus (n = 29) underwent comprehensive psychometric, audiometric, tinnitus matching, and acoustic stimulation procedures. Stimuli were presented for 3 minutes in two loudness regimes (60 dB sensation level [SL], minimum masking level [MML] + 6 dB, control sound: SL -6 dB) and amplitude modulated with 0, 10, or 40 Hz. Tinnitus loudness suppression was measured after the stimulation every 30 seconds. In addition, stimuli were rated regarding their valence and arousal. Results demonstrate only trends for better tinnitus suppression for the 10 Hz modulation and presentation level of 60 dB SL compared with PT, whereas nonsignificant results are reported for 40 Hz and MML + 6 dB, respectively. Furthermore, the 10 Hz AM at 60 dB SL and the 40 Hz AM at MML + 6 dB (trend) stimuli were better tolerated as elicited by valence ratings. We conclude that 10 Hz AM sounds at the tinnitus frequency may be useful to further elucidate the phenomenon of residual inhibition.

Amplitude Modulated Noise for Tinnitus Suppression in Tonal and Noise-Like Tinnitus.

BACKGROUND: The phenomenon of short-term tinnitus suppression by different forms of acoustic stimulation is referred to as residual inhibition (RI). RI can be triggered in the majority of tinnitus cases and was found to be depending on the used intensity, length or types of sounds. Past research already stressed the impact of noise stimulation as well as the superiority of amplitude modulated (AM) pure tones at the individual tinnitus frequency for RI in tonal tinnitus. Recently a novel approach for the determination of noise-like tinnitus characteristics was proposed. OBJECTIVES: The aim of the present study was to investigate whether in participants with noise-like tinnitus RI can be increased by AM noise stimuli according to the individual tinnitus frequency range. METHODS: For this purpose the individual tinnitus characteristics (noise-like and tonal tinnitus) of 29 people affected by tinnitus (mean age = 55.59, 7 females, mean tinnitus duration = 159.97 months) were assessed via customizable noise-band matching. The objective was to generate bandpass filtered stimuli according to the individual tinnitus sound (individualized bandpass filtered [IBP] sounds). Subsequently, various stimuli differing in bandpass filtering and AM were tested with respect to their potential to induce RI. Participants were acoustically stimulated with 7 different types of stimuli for 3 min each and had to rate the loudness of their tinnitus after each stimuli. RESULTS: Results indicate a general efficacy of noise stimuli for the temporary suppression of tinnitus, but no significant differences between AM and unmodulated IBP. Significantly better effects were observed for the subgroup with noise-like tinnitus (n = 14), especially directly after stimulation offset. CONCLUSIONS: The study at hand provides further insights in potential mechanisms behind RI for different types of tinnitus. Beyond that, derived principles may qualify for new or extend current tinnitus sound therapies.

Does Tinnitus Depend on Time-of-Day? An Ecological Momentary Assessment Study with the "TrackYourTinnitus" Application.

Only few previous studies used ecological momentary assessments to explore the time-of-day-dependence of tinnitus. The present study used data from the mobile application "TrackYourTinnitus" to explore whether tinnitus loudness and tinnitus distress fluctuate within a 24-h interval. Multilevel models were performed to account for the nested structure of assessments (level 1: 17,209 daily life assessments) nested within days (level 2: 3,570 days with at least three completed assessments), and days nested within participants (level 3: 350 participants). Results revealed a time-of-day-dependence of tinnitus. In particular, tinnitus was perceived as louder and more distressing during the night and early morning hours (from 12 a.m. to 8 a.m.) than during the upcoming day. Since previous studies suggested that stress (and stress-associated hormones) show a circadian rhythm and this might influence the time-of-day-dependence of tinnitus, we evaluated whether the described results change when statistically controlling for subjectively reported stress-levels. Correcting for subjective stress-levels, however, did not change the result that tinnitus (loudness and distress) was most severe at night and early morning. These results show that time-of-day contributes to the level of both tinnitus loudness and tinnitus distress. Possible implications of our results for the clinical management of tinnitus are that tailoring the timing of therapeutic interventions to the circadian rhythm of individual patients (chronotherapy) might be promising.

Validation of Online Versions of Tinnitus Questionnaires Translated into Swedish.

Background: Due to the lack of objective measures for assessing tinnitus, its clinical evaluation largely relies on the use of questionnaires and psychoacoustic tests. A global assessment of tinnitus burden would largely benefit from holistic approaches that not only incorporate measures of tinnitus but also take into account associated fears, emotional aspects (stress, anxiety, and depression), and quality of life. In Sweden, only a few instruments are available for assessing tinnitus, and the existing tools lack validation. Therefore, we translated a set of questionnaires into Swedish and evaluated their reliability and validity in a group of tinnitus subjects. Methods: We translated the English versions of the Tinnitus Functional Index (TFI), the Fear of Tinnitus Questionnaire (FTQ), the Tinnitus Catastrophizing Scale (TCS), the Perceived Stress Questionnaire (PSQ-30), and the Tinnitus Sample Case History Questionnaire (TSCHQ) into Swedish. These translations were delivered via the internet with the already existing Swedish versions of the Tinnitus Handicap Inventory (THI), the Hospital Anxiety and Depression Scale (HADS), the Hyperacusis Questionnaire (HQ), and the World Health Organization Quality of Life questionnaire (WHOQoL-BREF). Psychometric properties were evaluated by means of internal consistency [Cronbach's alpha (α)] and test-retest reliability across a 9-week interval [Intraclass Correlation Coefficient (ICC), Cohen's kappa] in order to establish construct as well as clinical validity using a sample of 260 subjects from a population-based cohort. Results: Internal consistency was acceptable for all questionnaires (α > 0.7) with the exception of the "social relationships" subscale of the WHOQoL-BREF. Test-retest reliability was generally acceptable (ICC > 0.70, Cohens kappa > 0.60) for the tinnitus-related questionnaires, except for the TFI "sense of control" subscale and 15 items of the TSCHQ. Spearmen rank correlations showed that almost all questionnaires on tinnitus are significantly related, indicating that these questionnaires measure different aspects of the same construct. The data supported good clinical validity of the tinnitus-related questionnaires. Conclusion: Our results suggest that most Swedish adaptations of the questionnaires are suitable for clinical and research settings and should facilitate the assessment of treatment outcomes using a more holistic approach by including measures of tinnitus fears, emotional burden, and quality of life.

A proof-of-concept study on the combination of repetitive transcranial magnetic stimulation and relaxation techniques in chronic tinnitus.

Interference of ongoing neuronal activity and brain stimulation motivated this study to combine repetitive transcranial magnetic stimulation (rTMS) and relaxation techniques in tinnitus patients. Forty-two patients were enrolled in this one-arm proof-of-concept study to receive ten sessions of rTMS applied to the left dorsolateral prefrontal cortex and temporo-parietal cortex. During stimulation, patients listened to five different kinds of relaxation audios. Variables of interest were tinnitus questionnaires, tinnitus numeric rating scales, depressivity, and quality of life. Results were compared to results of historical control groups having received the same rTMS protocol (active control) and sham treatment (placebo) without relaxation techniques. Thirty-eight patients completed the treatment, drop-out rates and adverse events were low. Responder rates (reduction in tinnitus questionnaire (TQ) score ≥5 points 10 weeks after treatment) were 44.7 % in the study, 27.8 % in the active control group, and 21.7 % in the placebo group, differing between groups on a near significant level. For the tinnitus handicap inventory (THI), the main effect of group was not significant. However, linear mixed model analyses showed that the relaxation/rTMS group differed significantly from the active control group showing steeper negative THI trend for the relaxation/rTMS group indicating better amelioration over the course of the trial. Deepness of relaxation during rTMS and selection of active relaxation vs. passive listening to music predicted larger TQ. All remaining secondary outcomes turned out non-significant. This combined treatment proved to be a safe, feasible and promising approach to enhance rTMS treatment effects in chronic tinnitus.

Onset-related differences in neural substrates of tinnitus-related distress: the anterior cingulate cortex in late-onset tinnitus, and the frontal cortex in early-onset tinnitus.

Recent findings regarding differences in tinnitus-related neural activity according to onset age have raised a question on possible onset age-related differences in neural substrates of distress. Hence we collected quantitative electroencephalography (qEEG) findings of 28 late-onset tinnitus (LOT) and 29 early-onset tinnitus (EOT) (mean onset age 52.3 and 29.0 years, respectively) participants. According to the tinnitus questionnaire (TQ) score grade, LOTs were then subdivided into 13 high distress (HD; TQ grade 3 or 4) and 15 low distress (LD; TQ grade 1 or 2), while EOTs into 14 HD and 15 LD. Compared to the EOT group, the LOT group demonstrated increased qEEG source-localized activity and functional connectivity primarily in the anterior cingulate cortex (ACC) and parahippocampus. In subgroup comparisons, the ACC was activated more in HD-LOT participants than in LD-LOT participants for the beta 1, beta 2 and gamma frequency bands, while the left orbitofrontal cortex and left dorsolateral prefrontal cortex were activated more in HD-EOT than in LD-EOT for the delta/beta and gamma frequency bands, respectively. Even with the same amount of tinnitus-related distress level, responsible neural substrates are different according to the onset age. These differences may be important for exploring different target areas of treatment according to tinnitus onset age, as well as for conducting similar studies on other pathologies, such as depression or pain.

Reduced variability of auditory alpha activity in chronic tinnitus.

Subjective tinnitus is characterized by the conscious perception of a phantom sound which is usually more prominent under silence. Resting state recordings without any auditory stimulation demonstrated a decrease of cortical alpha activity in temporal areas of subjects with an ongoing tinnitus perception. This is often interpreted as an indicator for enhanced excitability of the auditory cortex in tinnitus. In this study we want to further investigate this effect by analysing the moment-to-moment variability of the alpha activity in temporal areas. Magnetoencephalographic resting state recordings of 21 tinnitus subjects and 21 healthy controls were analysed with respect to the mean and the variability of spectral power in the alpha frequency band over temporal areas. A significant decrease of auditory alpha activity was detected for the low alpha frequency band (8-10 Hz) but not for the upper alpha band (10-12 Hz). Furthermore, we found a significant decrease of alpha variability for the tinnitus group. This result was significant for the lower alpha frequency range and not significant for the upper alpha frequencies. Tinnitus subjects with a longer history of tinnitus showed less variability of their auditory alpha activity which might be an indicator for reduced adaptability of the auditory cortex in chronic tinnitus.

Hyperacusis-associated pathological resting-state brain oscillations in the tinnitus brain: a hyperresponsiveness network with paradoxically inactive auditory cortex.

Although hyperacusis, a hyperresponsiveness to non-noxious auditory stimuli, is a sound-evoked symptom, possible resting-state pathologic oscillations in hyperacusis brain have never been explored. By comparing 17 tinnitus participants with hyperacusis (T+H+) and 17 without hyperacusis (T+H-), we aimed to explore characteristic resting-state cortical activity of hyperacusis. The T+H+ and T+H- groups, strictly matched for all tinnitus sound characteristics to exclude tinnitus-related cortical changes, were compared using resting-state electroencephalography source-localized activity complemented by functional connectivity analyses. Correlation analysis revealed that hyperacusis questionnaire score was positively correlated with the orbitofrontal cortex (OFC) beta power, the right auditory cortex (AC) alpha1 power, and the dorsal anterior cingulate cortex (dACC) beta1 power. Compared to the T+H- group, the T+H+ group demonstrated increased beta power in the dACC and OFC, and increased alpha power in the right AC. Region of interest analyses including 17 normal controls further confirmed that these differences originated solely from relatively increased power of the T+H+ group, not from a relative power decrease of the T+H- group. Also, the T+H+ group showed increased connectivity between the OFC/dACC and the AC as compared to the T+H- group. The beta power increase in the OFC/dACC may indicate increased resting-state vigilance in tinnitus patients with hyperacusis. In addition, increased alpha power in the AC may reflect an adaptive top-down inhibition against sound stimuli probably mediated by the increased beta power of the OFC. The OFC/dACC, also frequently found to be activated in analogous diseases such as allodynia/hyperalgesia, may compose a hyperresponsiveness network.

It's only in your head: expectancy of aversive auditory stimulation modulates stimulus-induced auditory cortical alpha desynchronization.

Increasing evidence underlines the functional importance of non-phase-locked cortical oscillatory rhythms. Among the different oscillations, alpha (8-12 Hz) has been shown to be modulated by anticipation or attention, suggesting a top-down influence. However, most studies to date have been conducted in the visual modality and the extent to which this notion also applies to the auditory cortex is unclear. It is furthermore often difficult to dissociate bottom-up from top-down contributions in cases of different stimuli (e.g., standards vs. deviants) or stimuli that are preceded by different cues. This study addresses these issues by investigating neuronal responses associated with intrinsically fluctuating perceptions of an invariant sound. Sixteen participants performed a pseudo-frequency-discrimination task in which a "high-pitch" tone was followed by an aversive noise, while the "low-pitch" tone was followed by silence. The participants had to decide which tone was presented even though the stimulus was actually kept constant while pseudo-randomized feedback was given. EEG data show that auditory cortical alpha power decreased by 20% in "high-pitch" trials relative to trials in which a "low pitch" was perceived. This study shows that expectancy of aversive feedback modulates perception of sounds and these fluctuating perceptions become manifest in modulations of sound-related alpha desynchronizations. Our findings extend recent evidence in the visual and somatosensory domain that alpha oscillations represent the excitatory/inhibitory balance of sensory cortical cell assemblies, which can be tuned in a top-down manner.

Short-term effects of single repetitive TMS sessions on auditory evoked activity in patients with chronic tinnitus.

Subjective tinnitus is the perception of a sound without any external source. Repetitive transcranial magnetic stimulation (rTMS) has been examined as a treatment tool for chronic tinnitus for several years trying to target hyperactivity/abnormal synchronization within the auditory cortex putatively underlying the auditory phantom percept. However, its exact impact on auditory cortical activity remains largely unknown. This study's objective was to systematically examine changes in auditory responses (N1, auditory steady-state response [aSSR]) measured by means of magnetoencephalography after single sessions of stimulation with different TMS paradigms. Subjects with chronic tinnitus (n = 10) underwent five sessions of rTMS in which they received one of five different stimulation protocols (1 Hz, individual alpha frequency, continuous theta burst stimulation [cTBS], intermittent theta burst stimulation [iTBS], and sham) in randomized order using a single-blind study design. Cortical steady-state responses to 40 Hz amplitude-modulated tones were measured before and after each magnetic stimulation protocol. The results demonstrate a reduction of the cortical response to the auditory steady-state stimulus after magnetic stimulation, whereas the N1 response was slightly enhanced or remained unchanged. Furthermore, reduction of the aSSR was driven by effects of iTBS, cTBS, and 1 Hz stimulation. Correspondingly, behavioral measures demonstrated the greatest reduction of tinnitus loudness after the respective rTMS protocols. The current study offers an interesting insight into the effects of rTMS on auditory cortical activity. The results of the study are discussed in the context of current limitations of TMS for the treatment of chronic tinnitus.

Using auditory steady state responses to outline the functional connectivity in the tinnitus brain.

BACKGROUND: Tinnitus is an auditory phantom perception that is most likely generated in the central nervous system. Most of the tinnitus research has concentrated on the auditory system. However, it was suggested recently that also non-auditory structures are involved in a global network that encodes subjective tinnitus. We tested this assumption using auditory steady state responses to entrain the tinnitus network and investigated long-range functional connectivity across various non-auditory brain regions. METHODS AND FINDINGS: Using whole-head magnetoencephalography we investigated cortical connectivity by means of phase synchronization in tinnitus subjects and healthy controls. We found evidence for a deviating pattern of long-range functional connectivity in tinnitus that was strongly correlated with individual ratings of the tinnitus percept. Phase couplings between the anterior cingulum and the right frontal lobe and phase couplings between the anterior cingulum and the right parietal lobe showed significant condition x group interactions and were correlated with the individual tinnitus distress ratings only in the tinnitus condition and not in the control conditions. CONCLUSIONS: To the best of our knowledge this is the first study that demonstrates existence of a global tinnitus network of long-range cortical connections outside the central auditory system. This result extends the current knowledge of how tinnitus is generated in the brain. We propose that this global extend of the tinnitus network is crucial for the continuos perception of the tinnitus tone and a therapeutical intervention that is able to change this network should result in relief of tinnitus.

Controversy: Does repetitive transcranial magnetic stimulation/ transcranial direct current stimulation show efficacy in treating tinnitus patients?

BACKGROUND: Tinnitus affects 10% of the population, its pathophysiology remains incompletely understood, and treatment is elusive. Functional imaging has demonstrated a relationship between the intensity of tinnitus and the degree of reorganization in the auditory cortex. Experimental studies have further shown that tinnitus is associated with synchronized hyperactivity in the auditory cortex. Therefore, targeted modulation of auditory cortex has been proposed as a new therapeutic approach for chronic tinnitus. METHODS: Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are noninvasive methods that can modulate cortical activity. These techniques have been applied in different ways in patients with chronic tinnitus. Single sessions of high-frequency rTMS over the temporal cortex have been successful in reducing the intensity of tinnitus during the time of stimulation and could be predictive for treatment outcome of chronic epidural stimulation using implanted electrodes. RESULTS: Another approach that uses rTMS as a treatment for tinnitus is application of low-frequency rTMS in repeated sessions, to induce a lasting change of neuronal activity in the auditory cortex beyond the duration of stimulation. Beneficial effects of this treatment have been consistently demonstrated in several small controlled studies. However, results are characterized by high interindividual variability and only a moderate decrease of the tinnitus. The role of patient-related (for example, hearing loss, tinnitus duration, age) and stimulation-related (for example, stimulation site, stimulation protocols) factors still remains to be elucidated. CONCLUSIONS: Even in this early stage of investigation, there is a convincing body of evidence that rTMS represents a promising tool for pathophysiological assessment and therapeutic management of tinnitus. Further development of this technique will depend on a more detailed understanding of the neurobiological effects mediating the benefit of TMS on tinnitus perception. Moreover clinical studies with larger sample sizes and longer follow-up periods are needed.

Tuning the tinnitus percept by modification of synchronous brain activity.

PURPOSE: Tinnitus, the perception of sound without the presence of a physical stimulus, provides the opportunity to study neural codes of percepts without simultaneous processing of stimuli. Previously, we have found that tinnitus is associated with enhanced delta- and reduced tau-power in temporal brain regions. By operantly modifying corresponding aspects of spontaneous EEG activity, the aim of the present study was to corroborate the assumption that tinnitus should be reduced if patterns of ongoing synchronous brain activity are normalised. METHODS: In response to different variants of neurofeedback, a total of twenty-one patients produced significant changes in EEG frequency bands. RESULTS: Simultaneous alteration of both frequency bands was strongly related to changes in tinnitus intensity matched before and after the intervention (r=-0.74). In those two patients with the greatest modulatory success, the tinnitus sensation resided completely in response to the treatment. Comparing the neurofeedback-treated patients with a group of patients trained with a frequency discrimination task (n=27), the tinnitus relief in the neurofeedback group was significantly stronger. CONCLUSIONS: This study supports the notion that altered patterns of intrinsic ongoing brain activity lead to phantom percepts and offer new routes to the treatment of tinnitus.

Neurofeedback for treating tinnitus.

Many individuals with tinnitus have abnormal oscillatory brain activity. Led by this finding, we have developed a way to normalize such pathological activity by neurofeedback techniques (Weisz et al. (2005). PLoS Med., 2: e153). This is achieved mainly through enhancement of tau activity, i.e., oscillatory activity produced in perisylvian regions within the alpha frequency range (8-12 Hz) and concomitant reduction in delta power range (0.5-4 Hz). This activity is recorded from electrodes placed on the frontal scalp. We have found that modification of the tau-to-delta ratio significantly reduces tinnitus intensity. Participants who successfully modified their oscillatory pattern profited from the treatment to the extent that the tinnitus sensation became completely abolished. Overall, this neurofeedback training was significantly superiorin reducing tinnitus-related distress than frequency discrimination training.