Placebos and Neurofeedback: A Case for Facilitating and Maximizing Placebo Response in Neurofeedback Treatments

A safety and feasibility randomized placebo controlled trial exploring electroencephalographic effective connectivity neurofeedback treatment for fibromyalgia

Fibromyalgia is a chronic pain condition contributing to significant disability worldwide. Neuroimaging studies identify abnormal effective connectivity between cortical areas responsible for descending pain modulation (pregenual anterior cingulate cortex, pgACC) and sensory components of pain experience (primary somatosensory cortex, S1). Neurofeedback, a brain-computer interface technique, can normalise dysfunctional brain activity, thereby improving pain and function. This study evaluates the safety, feasibility, and acceptability of a novel electroencephalography-based neurofeedback training, targeting effective alpha-band connectivity from the pgACC to S1 and exploring its effect on pain and function. Participants with fibromyalgia (N = 30; 15 = active, 15 = placebo) received 12 sessions of neurofeedback. Feasibility and outcome measures of pain (Brief Pain Inventory) and function (Revised Fibromyalgia Impact Questionnaire) were collected at baseline and immediately, ten-days, and one-month post-intervention. Descriptive statistics demonstrate effective connectivity neurofeedback training is feasible (recruitment rate: 6 participants per-month, mean adherence: 80.5%, dropout rate: 20%), safe (no adverse events) and highly acceptable (average 8.0/10) treatment approach for fibromyalgia. Active and placebo groups were comparable in their decrease in pain and functional impact. Future fully powered clinical trial is warranted to test the efficacy of the effective connectivity neurofeedback training in people with fibromyalgia with versus without chronic fatigue.

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.

An investigation of the effectiveness of neurofeedback training on motor performance in healthy adults: A systematic review and meta-analysis

Neurofeedback training (NFT) refers to a training where the participants voluntarily aim to manipulate their own brain activity using the sensory feedback abstracted from their brain activity. NFT has attracted attention in the field of motor learning due to its potential as an alternative or additional training method for general physical training. In this study, a systematic review of NFT studies for motor performance improvements in healthy adults and a meta-analysis on the effectiveness of NFT were conducted. A computerized search was performed using the databases Web of Science, Scopus, PubMed, JDreamIII, and Ichushi-Web to identify relevant studies published between January 1st, 1990, and August 3rd, 2021. Thirty-three studies were identified for the qualitative synthesis and 16 randomized controlled trials (374 subjects) for the meta-analysis. The meta-analysis, including all trials found in the search, revealed significant effects of NFT for motor performance improvement examined at the timing after the last NFT session (standardized mean difference = 0.85, 95% CI [0.18-1.51]), but with the existence of publication biases and substantial heterogeneity among the trials. Subsequent meta-regression analysis demonstrated the dose-response gradient between NFTs and motor performance improvements; more than 125 min of cumulative training time may benefit for the subsequent motor performance. For each motor performance measure (e.g., speed, accuracy, and hand dexterity), the effectiveness of NFT remains inconclusive, mainly due to its small sample sizes. More empirical NFT studies for motor performance improvement may be needed to show beneficial effects on motor performance and to safely incorporate NFT into real-world scenarios.

A Systematic Literature Review and Meta-analysis on Effectiveness of Neurofeedback for Obsessive-Compulsive Disorder

To evaluate the evidences related to the effectiveness of neurofeedback treatment for people with OCD. A literature review and meta-analysis of current controlled trials for patients with OCD symptoms was conducted across different databases. So, the primary outcome measure was OCD symptoms in subjects based on DSM IV. Y-BOCS was considered as primary outcomes. Nine met inclusion criteria (including 1211 patients). Analysis showed there was an important benefit of neurofeedback treatment in comparison to other treatments (MD = -6.815; 95% CI = [-9.033, -4.598]; P < 0.001). The results provide preliminary evidence that NFB is efficacious method for OCD and suggest that more clinical trials are needed to compare common treatment such as medication, neurological, and behavioral interventions.

The efficacy of biofeedback approaches for obsessive-compulsive and related disorders: A systematic review and meta-analysis

Biofeedback is applied to target excessive and/or deficient physiological signals to help patients identifying and self-managing their symptoms. Biofeedback has been employed in psychiatric disorders, including obsessive-compulsive disorder (OCD), mainly by using neural signals - neurofeedback. Recently, OCD has been integrated into the obsessive-compulsive and related disorders (OCD&RD) category (body dysmorphic, hoarding, trichotillomania/hair-pulling, and excoriation/skin-picking disorders). The efficacy of biofeedback for OCD&RD is still unknown. Our work provides a complete overview of publications assessing the therapeutic efficacy of biofeedback in OCD&RD with a systematic review and meta-analysis. We found ten studies involving 102 OCD participants (three randomized controlled trials) mostly applying neurofeedback (one publication used thermal biofeedback). Five neurofeedback studies were selected for meta-analysis (89 patients; two randomized controlled trials). The overall effect size within the treatment group varied between medium to large, but high heterogeneity and inconsistency values were found. The methodological quality was low indicating a high risk of bias. In conclusion, a beneficial effect of neurofeedback for OCD patients was found but also critical limitations on methodology, high heterogeneity among studies, and a putative reporting bias. Future research following high-quality guidelines should be conducted to address the efficacy of biofeedback approaches for OCD&RD.

Using Recent BCI Literature to Deepen our Understanding of Clinical Neurofeedback: A Short Review

In their recent paper, Alkoby et al. (2017) provide the readership with an extensive and very insightful review of the factors influencing NeuroFeedback (NF) performance. These factors are drawn from both the NF literature and the Brain-Computer Interface (BCI) literature. Our short review aims to complement Alkoby et al.'s review by reporting recent additions to the BCI literature. The object of this paper is to highlight this literature and discuss its potential relevance and usefulness to better understand the processes underlying NF and further improve the design of clinical trials assessing NF efficacy. Indeed, we are convinced that while NF and BCI are fundamentally different in many ways, both the BCI and NF communities could reach compelling achievements by building upon one another. By reviewing the recent BCI literature, we identified three types of factors that influence BCI performance: task-specific, cognitive/motivational and technology-acceptance-related factors. Since BCIs and NF share a common goal (i.e., learning to modulate specific neurophysiological patterns), similar cognitive and neurophysiological processes are likely to be involved during the training process. Thus, the literature on BCI training may help (1) to deepen our understanding of neurofeedback training processes and (2) to understand the variables that influence the clinical efficacy of NF. This may help to properly assess and/or control the influence of these variables during randomized controlled trials.

Neurofeedback for Traumatic Brain Injury: Current Trends

Traumatic brain injuries constitute significant health and societal problems which can be ameliorated with some recent developments in neurofeedback. The field of neurofeedback has evolved from single channel to multiple-site training, and with LORETA Z-score training, deeper levels of the brain can reached. Neurofeedback for traumatic brain injury patients may provide improvements never before possible.