Neurofeedback for Tinnitus Treatment - Review and Current Concepts

The potential of infra-low frequency neurofeedback training in peak performance: The first double-blinded placebo-controlled longitudinal study in healthy adults

Infra-low frequency neurofeedback training (ILF-NFT) has shown promise in addressing cognitive and affective distress symptoms across a range of psychiatric disorders. This study tested ILF-NFT's effects in a double-blinded, placebo-controlled longitudinal context in healthy psychology students. Across five weeks, forty-two healthy psychology students (aged 18-35) were randomly allocated into two groups, receiving ten sessions of 30 minutes of active and sham ILF-NFT. Dependent variables were measured before, following, and two months after the intervention and were comprised of: heartrate variability assessments as a measure of stress resilience; digit span, n-back, trail making and go-no-go task measures of executive functioning performance; and SCL-90-R, WHOQOL-Bref, and peak performance measures of subjective self-report. Statistical analysis was performed using an ANCOVA and compared across groups correcting for baseline differences and multiple comparisons. ANCOVA analyses revealed no significant differences across active and placebo groups in any dependent variables, when correcting for multiple comparisons. Thus, the remaining analyses focused on questionnaire correlations. Here, significant correlations were observed between the novel peak performance questionnaire with the SCL-90-R and WHOQOL-Bref, confirming its construct and retest validity. Despite several methodological limitations, including a potential type-2 error, this study highlights limited effects of ILF-NFT in healthy volunteers. Future research should thus focus on clinically driven experimental designs to explore ILF-NFT's potential in psychiatric contexts. Further research utilization of the novel peak performance questionnaire is recommended for measures of peak performance.

EEG spectral and microstate analysis originating residual inhibition of tinnitus induced by tailor-made notched music training

Tailor-made notched music training (TMNMT) is a promising therapy for tinnitus. Residual inhibition (RI) is one of the few interventions that can temporarily inhibit tinnitus, which is a useful technique that can be applied to tinnitus research and explore tinnitus mechanisms. In this study, RI effect of TMNMT in tinnitus was investigated mainly using behavioral tests, EEG spectral and microstate analysis. To our knowledge, this study is the first to investigate RI effect of TMNMT. A total of 44 participants with tinnitus were divided into TMNMT group (22 participants; ECnm, NMnm, RInm represent that EEG recordings with eyes closed stimuli-pre, stimuli-ing, stimuli-post by TMNMT music, respectively) and Placebo control group (22 participants; ECpb, PBpb, RIpb represent that EEG recordings with eyes closed stimuli-pre, stimuli-ing, stimuli-post by Placebo music, respectively) in a single-blind manner. Behavioral tests, EEG spectral analysis (covering delta, theta, alpha, beta, gamma frequency bands) and microstate analysis (involving four microstate classes, A to D) were employed to evaluate RI effect of TMNMT. The results of the study showed that TMNMT had a stronger inhibition ability and longer inhibition time according to the behavioral tests compared to Placebo. Spectral analysis showed that RI effect of TMNMT increased significantly the power spectral density (PSD) of delta, theta bands and decreased significantly the PSD of alpha2 band, and microstate analysis showed that RI effect of TMNMT had shorter duration (microstate B, microstate C), higher Occurrence (microstate A, microstate C, microstate D), Coverage (microstate A) and transition probabilities (microstate A to microstate B, microstate A to microstate D and microstate D to microstate A). Meanwhile, RI effect of Placebo decreased significantly the PSD of alpha2 band, and microstate analysis showed that RI effect of Placebo had shorter duration (microstate C, microstate D), higher occurrence (microstate B, microstate C), lower coverage (microstate C, microstate D), higher transition probabilities (microstate A to microstate B, microstate B to microstate A). It was also found that the intensity of tinnitus symptoms was significant positively correlated with the duration of microstate B in five subgroups (ECnm, NMnm, RInm, ECpb, PBpb). Our study provided valuable experimental evidence and practical applications for the effectiveness of TMNMT as a novel music therapy for tinnitus. The observed stronger residual inhibition (RI) ability of TMNMT supported its potential applications in tinnitus treatment. Furthermore, the temporal dynamics of EEG microstates serve as novel functional and trait markers of synchronous brain activity that contribute to a deep understanding of the neural mechanism underlying TMNMT treatment for tinnitus.

Neurofeedback for tinnitus treatment: an innovative method with promising potential

This scientific commentary refers to 'Does it matter what is trained? A randomized controlled trial evaluating the specificity of alpha/delta ratio neurofeedback in reducing tinnitus symptoms 'by Jensen et al. (https://doi.org/10.1093/braincomms/fcad185).

Does it matter what is trained? A randomized controlled trial evaluating the specificity of alpha/delta ratio neurofeedback in reducing tinnitus symptoms

Previous studies showed that alpha/delta ratio neurofeedback was effective in reducing unpleasant psychological, emotional and perceptual consequences of tinnitus. The main goal of the present study was to investigate, whether the specific combination of enhancing alpha frequency band activity and reducing delta frequency band activity was necessary, or merely sufficient, to obtain a positive treatment outcome regarding tinnitus distress and intensity. A second research aim was to assess the relative contribution of neurofeedback-related non-specific and general non-specific effects in neurofeedback treatment. In a three-arm, randomized controlled trial, 94 chronic tinnitus patients were randomly assigned to one of three conditions: alpha/delta ratio neurofeedback (n = 31), beta/theta ratio neurofeedback (n = 28) and non-neurofeedback minimal treatment intervention (n = 35). Neurofeedback participants underwent 10 treatment sessions over a 4-week period. Outcome measures were collected pre-, mid- and post-interventions and at 3-months follow-up. The Tinnitus Handicap Inventory and the Tinnitus Magnitude Index were used as primary outcome measures for tinnitus distress and tinnitus intensity. EEG data recorded during training supplemented primary outcomes. Since data were repeated measures, the analyses used a two-level mixed effects model approach including by-subject random effects (random intercept). For the Tinnitus Handicap Inventory, the results showed no interaction effect. For the Tinnitus Magnitude Index, the analysis showed a significant time × group interaction, indicating that both alpha/delta ratio neurofeedback and beta/theta ratio neurofeedback reported reduced tinnitus intensity. Analysis of EEG data showed a consistent pattern for the alpha/delta ratio over the course of training. Compared to beta/theta ratio neurofeedback, alpha/delta ratio neurofeedback showed an elevated response. Conversely, for the beta ratio to theta ratio, the pattern was more inconsistent, with no clear indication of superiority for beta/theta ratio neurofeedback over alpha/delta ratio neurofeedback. The main question of this piece of research was whether alpha/delta ratio neurofeedback demonstrated frequency band specificity in the alleviation of tinnitus distress and perceived intensity. Results showed that alpha/delta ratio neurofeedback was sufficient but importantly 'not' necessary to achieve a positive outcome on both the Tinnitus Handicap Inventory and Tinnitus Magnitude Index, when compared to beta/theta ratio neurofeedback. Still, the data suggest a trend towards specificity for alpha/delta ratio neurofeedback. Because of this, it may be too premature to discard alpha/delta ratio neurofeedback in the treatment of tinnitus. Recommendations for future studies are outlined.

Infra-low frequency neurofeedback training in Dravet syndrome: A case study

This case study examines how an intervention of infra-low frequency neurofeedback training (ILF-NFT) affects the symptomatology of an eight-year-old patient with Dravet syndrome (DS), a rare and highly disabling form of epilepsy. Our results demonstrate that ILF-NFT has improved the patient's sleep disturbance, has significantly reduced seizure frequency and severity, and has reversed neurodevelopmental decline, with positive development in intellectual and motor skills. No significant changes have been made to the patient's medication in the observed period of 2.5 years. Thus, we draw attention to ILF-NFT as a promising intervention in addressing DS symptomatology. Finally, we discuss the study's methodological limitations and warrant future studies to assess the effect of ILF-NFT in DS in more elaborate research designs.

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.

Recovering Hidden Responder Groups in Individuals Receiving Neurofeedback for Tinnitus

The widespread understanding that chronic tinnitus is a heterogeneous phenomenon with various neural oscillatory profiles has spurred investigations into individualized approaches in its treatment. Neurofeedback, as a non-invasive tool for altering neural activity, has become increasingly popular in the personalized treatment of a wide range of neuropsychological disorders. Despite the success of neurofeedback on the group level, the variability in the treatment efficacy on the individual level is high, and evidence from recent studies shows that only a small number of people can effectively modulate the desired aspects of neural activity. To reveal who may be more suitable, and hence benefit most from neurofeedback treatment, we classified individuals into unobserved subgroups with similar oscillatory trajectories during the treatment and investigated how subgroup membership was predicted by a series of characteristics. Growth mixture modeling was used to identify distinct latent subgroups with similar oscillatory trajectories among 50 individuals suffering from chronic subjective tinnitus (38 male, 12 female, mean age = 47.1 ± 12.84) across 15 neurofeedback training sessions. Further, the impact of characteristics and how they predicted the affiliation in the identified subgroups was evaluated by including measures of demographics, tinnitus-specific (Tinnitus Handicap Inventory) and depression variables, as well as subjective quality of life subscales (World Health Organization—Quality of Life Questionnaire), and health-related quality of life subscales (Short Form-36) in a logistic regression analysis. A latent class model could be fitted to the longitudinal data with a high probability of correctly classifying distinct oscillatory patterns into 3 different groups: non-responder (80%), responder (16%), and decliner (4%). Further, our results show that the health-related wellbeing subscale of the Short Form-36 questionnaire was differentially associated with the groups. However, due to the small sample size in the Responder group, we are not able to provide sufficient evidence for a distinct responder profile. Nevertheless, the identification of oscillatory change-rate differences across distinct groups of individuals provides the groundwork from which to tease apart the complex and heterogeneous oscillatory processes underlying tinnitus and the attempts to modify these through neurofeedback. While more research is needed, our results and the analytical approach presented may bring clarity to contradictory past findings in the field of tinnitus research, and eventually influence clinical practice.

Symptom dimensions to address heterogeneity in tinnitus

Tinnitus, the auditory phantom percept, is a well-known heterogenous disorder with multiple subtypes. Researchers and clinicians have tried to classify these subtypes according to clinical profiles, aetiologies, and response to treatment with little success. The occurrence of overlapping tinnitus subtypes suggests that the disorder exists along a continuum of severity, with no clear distinct boundaries. In this perspective, we propose a neuro-mechanical framework, viewing tinnitus as a dimensional disorder which is a complex interplay of its behavioural, biological and neurophysiological phenotypes. Moreover, we explore the potential of these dimensions as interacting networks without a common existing cause, giving rise to tinnitus. Considering tinnitus as partially overlapping, dynamically changing, interacting networks, each representing a different aspect of the unified tinnitus percept, suggests that the interaction of these networks determines the phenomenology of the tinnitus, ultimately leading to a dimensional spectrum, rather than a categorical subtyping. A combination of a robust theoretical framework and strong empirical evidence can advance our understanding of the functional mechanisms underlying tinnitus and ultimately, improve treatment strategies.

Bayesian brain in tinnitus: Computational modeling of three perceptual phenomena using a modified Hierarchical Gaussian Filter

Recently, Bayesian brain-based models emerged as a possible composite of existing theories, providing an universal explanation of tinnitus phenomena. Yet, the involvement of multiple synergistic mechanisms complicates the identification of behavioral and physiological evidence. To overcome this, an empirically tested computational model could support the evaluation of theoretical hypotheses by intrinsically encompassing different mechanisms. The aim of this work was to develop a generative computational tinnitus perception model based on the Bayesian brain concept. The behavioral responses of 46 tinnitus subjects who underwent ten consecutive residual inhibition assessments were used for model fitting. Our model was able to replicate the behavioral responses during residual inhibition in our cohort (median linear correlation coefficient of 0.79). Using the same model, we simulated two additional tinnitus phenomena: residual excitation and occurrence of tinnitus in non-tinnitus subjects after sensory deprivation. In the simulations, the trajectories of the model were consistent with previously obtained behavioral and physiological observations. Our work introduces generative computational modeling to the research field of tinnitus. It has the potential to quantitatively link experimental observations to theoretical hypotheses and to support the search for neural signatures of tinnitus by finding correlates between the latent variables of the model and measured physiological data.

Application of Latent Growth Curve modeling to predict individual trajectories during neurofeedback treatment for tinnitus

Tinnitus is a heterogeneous phenomenon indexed by various EEG oscillatory profiles. Applying neurofeedback (NFB) with the aim of changing these oscillatory patterns not only provides help for those who suffer from the phantom percept, but a promising foundation from which to probe influential factors. The reliable attribution of influential factors that potentially predict oscillatory changes during the course of NFB training may lead to the identification of subgroups of individuals that are more or less responsive to NFB training. The present study investigated oscillatory trajectories of delta (3-4Hz) and individual alpha (8.5-12Hz) during 15 NFB training sessions, based on a Latent Growth Curve framework. First, we found the desired enhancement of alpha, while delta was stable throughout the NFB training. Individual differences in tinnitus-specific variables and general-, as well as health-related quality of life predictors were largely unrelated to oscillatory change prior to and across the training. Only the predictors age and sex at baseline were clearly related to slow-wave delta, particularly so for older female individuals who showed higher delta power values from the start. Second, we confirmed a hierarchical cross-frequency association between the two frequency bands; however, in opposing directions to those anticipated in tinnitus. The establishment of individually tailored NFB protocols would boost this therapy's effectiveness in the treatment of tinnitus. In our analysis, we propose a conceptual groundwork toward this goal of developing more targeted treatment.

Emerging Topics in the Behavioral Neuroscience of Tinnitus

This volume has highlighted the many recent advances in tinnitus theory, models, diagnostics, therapies, and therapeutics. But tinnitus knowledge is far from complete. In this chapter, contributors to the Behavioral Neuroscience of Tinnitus consider emerging topics and areas of research needed in light of recent findings. New research avenues and methods to explore are discussed. Issues pertaining to current assessment, treatment, and research methods are outlined, along with recommendations on new avenues to explore with research.

Electrophysiological correlates of focused attention on low- and high-distressed tinnitus

OBJECTIVES

The study aimed at determining the EEG correlates of concentration on either low or high-distressed tinnitus.

METHODS

Sixty-seven patients (36 women, mean age = 50.34 ± 12.94 years) with chronic tinnitus were assigned to either a high (HD) or low (LD) tinnitus-related distress group based on THI results. All participants took part in the EEG study comprising two 3-4 min blocks of focusing on either tinnitus (Tinnitus Focus Condition, TFC) or the sensations from one's own body (Body Focus Condition, BFC). The absolute power and current density of 8 frequency bands in 7 clusters were compared between conditions and groups.

RESULTS

The most pronounced differences were found in the HD patients in the TFC, relative to the BFC, i.e. reduced power of frontally distributed low alpha (8-10 Hz) and posterior high alpha (10-12 Hz) as well as lower current density of 8-10 Hz rhythm over the right frontal/anterior cingulate cortex and higher middle beta (15-18 Hz) density in the precuneus. The HD, relative to LD patients, in both conditions, exhibited increased low beta (12-15 Hz) power over the left middle area and greater higher beta (15-25 Hz) power in the left posterior region.

CONCLUSIONS

The present study contrasted bioelectrical activity, acquired when concentrating on tinnitus with EEG data collected whilst patients focused on their body. Decreased alpha power and current density in the frontal/cingulate cortex when listening to bothersome tinnitus might reflect greater cortical arousal whereas increased beta power and density in the precuneus/posterior cingulate activity in this condition could be indicative for elevated tension or augmented cognitive/emotional processing of tinnitus sound. Enhanced beta rhythm in patients with high versus low tinnitus distress, observed independently of the study condition, may be due to greater self-focused attention or more active processing of sensations derived from the own body.

Combining neurofeedback with source estimation: Evaluation of an sLORETA neurofeedback protocol for chronic tinnitus treatment

Background:

Alpha/delta neurofeedback has been shown to be a potential treatment option for chronic subjective tinnitus. Traditional neurofeedback approaches working with a handful of surface electrodes have been criticized, however, due to their low spatial specificity.

Objective:

The purpose of this study was to evaluate an innovative tomographic neurofeedback protocol that combines neural activity measured across the whole scalp with sLORETA source estimation.

Methods:

Forty-eight tinnitus patients participated in 15 neurofeedback training sessions as well as extensive pre, post, and follow-up testing. Patients were randomly assigned to either a tomographic (TONF) or a traditional electrode-based neurofeedback (NTNF) group. Main outcome measures of this study were defined as tinnitus-related distress measured with the Tinnitus Handicap Inventory (THI) and Tinnitus Questionnaire (TQ), tinnitus loudness, and resting-state EEG activity in trained frequency bands.

Results:

For both groups a significant reduction of tinnitus-related distress and tinnitus loudness was found. While distress changes remained persistent irrespective of group, loudness levels returned to baseline in the follow-up period. No significant between-group differences between the 2 neurofeedback applications (TONF vs. NTNF) were found, which suggests a similar contribution to symptom improvement. The trained alpha/delta ratio increased significantly over the course of the training and remained stable in the follow-up period. This effect was found irrespective of group on both surface and source levels with no meaningful differences between the 2 groups.

Conclusions:

Our study shows that a tomographic alpha/delta protocol should be considered a promising addition to tinnitus treatment but that more individually specific neurofeedback protocols should be developed.

Neurofeedback for tinnitus: study protocol for a randomised controlled trial assessing the specificity of an alpha/delta neurofeedback training protocol in alleviating both sound perception and psychological distress in a cohort of chronic tinnitus sufferers

BACKGROUND

Tinnitus is a particularly common condition and can have debilitating psychological consequences for certain people. Although several interventions have been helpful in teaching individuals to better cope with tinnitus, no cure exists at present. Neurofeedback is an emerging treatment modality in tinnitus. Previous studies, utilising an alpha/delta training protocol, have shown promise. However, they were characterised by small sample sizes and a lack of neurofeedback control conditions. Therefore, the aim of this study is to investigate whether an alpha/delta neurofeedback training protocol, compared to beta/theta neurofeedback or a diary control group, is effective in reducing not only the tinnitus sound perception but also the psychological symptoms associated with the condition.

METHODS

The study is designed as a three-armed randomised controlled trial. Participants are randomly assigned to a) an established neurofeedback protocol for tinnitus (alpha/delta training), b) an active control group (beta/theta training) or c) a diary control group. In the 4-week intervention period, participants in both neurofeedback groups undergo 10 sessions, whereas participants in the diary control group complete a bi-weekly diary. The primary outcomes are between group differences in tinnitus sound perception change, as measured with the Tinnitus Magnitude Index (TMI), and changes in tinnitus distress, measured with the Tinnitus Handicap Inventory (THI), 4 weeks after the start of the intervention. Secondary outcome measures include changes in tinnitus distress, sleep quality, depressive symptoms and whether neurofeedback leads to specific power changes in the trained frequency bands.

DISCUSSION

This is the first randomised controlled trial examining the efficacy of an alpha/delta neurofeedback training protocol in reducing tinnitus sound perception and the distress associated with the condition. Compared to former studies, the present study is designed to assess both the specificity of an alpha/delta neurofeedback training protocol by including an active comparator and beta/theta neurofeedback training, in addition to controlling for placebo effects by the inclusion of a diary control group. This study aims to contribute to an understanding of the influences of both specific and non-specific effects in neurofeedback treatment for tinnitus.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03550430. Registered on 27 May 2018.

Avenue for Future Tinnitus Treatments

Tinnitus is a common symptom. Standard therapies aim at improving the quality of life and reducing the psychological stress associated with tinnitus. Most interventions have little or no effect on the main symptom. Those affected subjects, however, want such a change and prefer a specific solution, such as pharmacologic therapy to other modalities. Scientific efforts have not yet led to significant improvement in the range of therapies. This article outlines existing efforts and develops ideas on how research for improved tinnitus therapy might look in the future.

Accounting for Heterogeneity: Mixed-Effects Models in Resting-State EEG Data in a Sample of Tinnitus Sufferers

In neuroscience, neural oscillations and other features of brain activity recorded by electroencephalography (EEG) are typically statistically assessed on the basis of the study’s population mean to identify possible blueprints for healthy subjects, or subjects with diagnosable neurological or psychiatric disorders. Despite some inter-individual similarities, there is reason to believe that a discernible portion of the individual brain activity is subject-specific. In order to encompass the potential individual source of variance in EEG data and psychometric parameters, we introduce an innovative application of linear mixed-effects models (LMM) as an alternative procedure for the analysis of resting-state EEG data. Using LMM, individual differences can be modelled through the assumptions of idiosyncrasy of all responses and dependency among data points (e.g., from the same subject within and across units of time) via random effects parameters. This report provides an example of how LMM can be used for the statistical analysis of resting-state EEG data in a heterogeneous group of subjects; namely, people who suffer from tinnitus (ringing in the ear/s). Results from 49 participants (38 male, mean age of 46.69 ± 12.65 years) revealed that EEG signals were not only associated with specific recording sites, but exhibited regional specific oscillations in conjunction to symptom severity. Tinnitus distress targeted the frequency bands beta3 (23.5–35 Hz) and gamma (35.5–45 Hz) in right frontal regions, whereas delta (0.5–4 Hz) exhibited significant changes in temporal-parietal sources. Further, 57.8% of the total variance in EEG power was subject-specific and acknowledged by the LMM framework and its prediction. Thus, a deeper understanding of both the underlying statistical and physiological patterns of EEG data was gained.

Smartphone Apps in the Context of Tinnitus: Systematic Review

Smartphones containing sophisticated high-end hardware and offering high computational capabilities at extremely manageable costs have become mainstream and an integral part of users' lives. Widespread adoption of smartphone devices has encouraged the development of many smartphone applications, resulting in a well-established ecosystem, which is easily discoverable and accessible via respective marketplaces of differing mobile platforms. These smartphone applications are no longer exclusively limited to entertainment purposes but are increasingly established in the scientific and medical field. In the context of tinnitus, the ringing in the ear, these smartphone apps range from relief, management, self-help, all the way to interfacing external sensors to better understand the phenomenon. In this paper, we aim to bring forth the smartphone applications in and around tinnitus. Based on the PRISMA guidelines, we systematically analyze and investigate the current state of smartphone apps, that are directly applied in the context of tinnitus. In particular, we explore Google Scholar, CiteSeerX, Microsoft Academics, Semantic Scholar for the identification of scientific contributions. Additionally, we search and explore Google's Play and Apple's App Stores to identify relevant smartphone apps and their respective properties. This review work gives (1) an up-to-date overview of existing apps, and (2) lists and discusses scientific literature pertaining to the smartphone apps used within the context of tinnitus.

Real-time monitoring and regulating auditory cortex alpha activity in patients with chronic tinnitus

OBJECTIVE

Low levels of alpha activity (8-13Hz) mirror a state of enhanced responsiveness, whereas high levels of alpha are a state of reduced responsiveness. Tinnitus is accompanied by reduction of alpha activity in the perisylvian regions compared to normal hearing controls. This reduction might be a key mechanism in the chain of reactions leading to tinnitus. We devised a novel spatial filter as an on-line source monitoring method, which can be used to control alpha activity in the primary auditory cortex. In addition, we designed an innovative experimental procedure to enable suppression of visual and somatosensory alpha, facilitating auditory alpha control during alpha neurofeedback.

APPROACH

An amplitude-modulated auditory stimulation with 40 Hz modulation frequency and 1000 Hz carrier frequency specifically activates the primary auditory cortex. The topography of 40 Hz oscillation depicts the activity of the auditory cortices. We used this map as a spatial filter, which passes the activity originating from the auditory cortex. To suppress superposition of auditory alpha by somatosensory and visual alpha, we used a continuous tactile jaw-stimulation and visual stimulation protocol to suppress somatosensory alpha of regions adjacent to the auditory cortex and visual alpha for local regulation of auditory alpha activity only.

MAIN RESULTS

This novel spatial filter for online detection of auditory alpha activity and the usage of multi-sensory stimulation facilitate the appearance of alpha activity from the auditory cortex at the sensor level.

SIGNIFICANCE

The proposed procedure can be used in an EEG-neurofeedback-treatment approach allowing online auditory alpha self-regulation training in patients with chronic tinnitus.

An association between marijuana use and tinnitus

OBJECTIVE

While some advocates have argued for marijuana as a treatment for tinnitus, the relationship between marijuana use and tinnitus is unknown. The objective of this study was to evaluate associations between marijuana use and the prevalence, severity, and rate of occurrence of tinnitus.

STUDY DESIGN

Cross-sectional analysis of nationally representative data.

SETTING

National Health and Nutrition Examination Survey 2011-2012.

SUBJECTS AND METHODS

Statistical analysis was performed on data collected from 2705 non-institutionalized adults aged 20-69 who underwent audiometric testing and were administered questionnaires about hearing, drug use, current health status, and medical history.

RESULTS

The use of marijuana at least once per month for the previous 12 months was significantly associated with experiencing tinnitus during that 12-month month (X²(1) = 19.41, p < 0.001). Subjects who used marijuana were more likely to experience tinnitus after accounting for covariables including age, gender, audiometric hearing loss, noise exposure history, depression, anxiety, smoking, salicylate use, cardiovascular disease, hypertension, and diabetes (OR = 1.75, 95% CI 1.02-3.01, p = 0.043). There were no associations between the severity or frequency of tinnitus occurrence and the quantity or frequency of marijuana use. Use of other substances such as alcohol, cocaine, methamphetamine, and heroin was not associated with tinnitus.

CONCLUSION

Regular marijuana use is associated with prevalent tinnitus. However, no dose response between marijuana use and tinnitus was observed. The relationship between marijuana use and tinnitus is complex and is likely modulated by psychosocial factors.

Investigating the Efficacy of an Individualized Alpha/Delta Neurofeedback Protocol in the Treatment of Chronic Tinnitus

First attempts have demonstrated that the application of alpha/delta neurofeedback in the treatment of chronic tinnitus leads to a reduction of symptoms at the group level. However, recent research also suggests that chronic tinnitus is a decidedly heterogeneous phenomenon, one that requires treatment of distinct subgroups or even on an individual level. Thus, the purpose of this study was to evaluate an individually adjusted alpha/delta neurofeedback protocol. Following previous studies, the delta band fixed between 3 and 4 Hz was chosen as the frequency for inhibition. However, unlike the previous studies, the frequency range for the rewarded alpha band was not fixed between 8 and 12 Hz but rather individually determined according to each patient's specific alpha peak frequency (IAF). Twenty-six chronic tinnitus patients participated in 15 weekly neurofeedback training sessions and extensive pre- and post-tests, as well as follow-up testing 3 and 6 months after training. The main outcome measures were tinnitus-related distress measured with the Tinnitus Handicap Inventory (THI) and Tinnitus Questionnaire (TQ), tinnitus loudness, and pre- and post-training resting-state EEG activity in trained frequency bands. In Results, the neurofeedback protocol led to a significant reduction of tinnitus-related distress and tinnitus loudness. While distress remained on a low level even 6 months after the completion of training, loudness returned to baseline levels in the follow-up period. In addition, resting-state EEG activity showed an increase in the trained alpha/delta ratio over the course of the training. This ratio increase was related to training-induced changes of tinnitus-related distress as measured with TQ, mainly due to increases in the alpha frequency range. In sum, this study confirms the alpha/delta neurofeedback as a suitable option for the treatment of chronic tinnitus and represents a first step towards the development of individual neurofeedback protocols. This clinical trial was registered online at ClinicalTrials.gov (NCT02383147) and kofam.ch (SNCTP000001313).

Neurofeedback: Principles, appraisal, and outstanding issues

Neurofeedback is a form of brain training in which subjects are fed back information about some measure of their brain activity which they are instructed to modify in a way thought to be functionally advantageous. Over the last 20 years, neurofeedback has been used to treat various neurological and psychiatric conditions, and to improve cognitive function in various contexts. However, in spite of a growing popularity, neurofeedback protocols typically make (often covert) assumptions on what aspects of brain activity to target, where in the brain to act and how, which have far-reaching implications for the assessment of its potential and efficacy. Here we critically examine some conceptual and methodological issues associated with the way neurofeedback's general objectives and neural targets are defined. The neural mechanisms through which neurofeedback may act at various spatial and temporal scales, and the way its efficacy is appraised are reviewed, and the extent to which neurofeedback may be used to control functional brain activity discussed. Finally, it is proposed that gauging neurofeedback's potential, as well as assessing and improving its efficacy will require better understanding of various fundamental aspects of brain dynamics and a more precise definition of functional brain activity and brain-behaviour relationships.