Mechanisms underlying fNIRS-neurofeedback over the prefrontal cortex for participants with binge-eating disorder

A systematic review on the role of EEG and fMRI-Neurofeedback training in the treatment of substance use disorders and behavioral addiction

Neurofeedback (NF), a form of biofeedback, is used to enhance the self-regulation of brain functions by assessing brain activity and delivering feedback signals to ameliorate emotional attributes, cognitive functions, and behaviors. Despite the potential role of NF in substance use disorder (SUD) treatment, a number of gaps such as variations in NF methods persist. This study aims to address such gaps and present comprehensive insights into EEG and fMRI-NF applications in SUD management. This study has been conducted according to the PRISMA guidelines. The search spanned four major databases: Web of Science, Scopus, PubMed, and Embase. The search terms encompassed "Neurofeedback" OR "EEG biofeedback" OR "neurotherapy" OR "Functional near-infrared spectroscopy Neurofeedback" OR "fNIRS-Neurofeedback" AND addiction OR Drug OR "substance dependence" OR "substance abuse" OR Heroin OR Opioid OR Cannabis OR Marihuana OR Cocaine OR Crack OR Amphetamine OR Methamphetamine OR Hallucinogen. Our systematic review yielded 32 articles, including 18 EEG-, 11 fMRI-neurofeedback, and 3 fNIRS-neurofeedback studies. The primary outcome was reduced drug craving and some aspects of mental health and EEG-NF studies consistently indicated a preference for the alpha-theta protocol, whereas the high heterogeneity among fMRI-NF protocols limited direct comparisons. In conclusion, the results of this systematic review indicate that NF shows promise as an adjunctive intervention for treating SUD.

Reward and Inhibitory Control as Mechanisms and Treatment Targets for Binge Eating Disorder

PURPOSE OF REVIEW

Recent research has highlighted alterations in reward and inhibitory control among individuals with binge eating disorder, identifying both constructs as potential targets for treatment. Treatments targeting reward and inhibitory control for binge eating disorder are emerging. This review aims to summarize the recent literature evaluating reward and inhibitory control in binge eating disorder compared to weight-matched controls using behavioral paradigms and neuroimaging. This review also aims to summarize recent literature evaluating treatments for binge eating targeting these mechanisms and highlights additional work needed in these areas.

RECENT FINDINGS

Reward hypersensitivity and impaired inhibitory control are mechanisms underlying binge eating disorder. Individuals with binge eating disorder experience higher initial reward to food, and later, higher anticipatory reward but lower experienced food reward which maintains binge eating behavior. Treatments targeting reward and inhibitory control for binge eating include behavioral, computerized trainings, pharmacological, and neuromodulation treatments. The majority of trials are small but demonstrate promise in reducing binge eating and targeting theorized mechanisms. Larger, randomized trials are needed. Changes in reward and inhibitory control are present in individuals with binge eating disorder and treatments targeting these mechanisms demonstrate initial promise. Greater research is needed evaluating reward and inhibitory control simultaneously and with weight-matched comparison groups, as well as larger randomized trials that target both processes simultaneously.

Neurofeedback strategies in binge-eating disorder as predictors of EEG-neurofeedback regulation success

Introduction

Treatment options such as neurofeedback (NF) that directly target the link between aberrant brain activity patterns and dysfunctional eating behaviors in binge-eating disorder (BED) are emerging. However, virtually nothing is known about mental strategies used to modulate food-specific brain activity and the associated brain-based or subjective success of specific strategies. This study firstly investigated the use of mental strategies in response to individually appetitive food cues in adults with BED and overweight or obesity based on a randomized-controlled trial providing electroencephalography (EEG)- or real-time functional near-infrared spectroscopy (rtfNIRS)-NF to BED.

Methods

Strategy reports written by participants were classified with qualitative content analysis. Additionally, the mental strategies employed by the N = 23 patients who received EEG-NF targeting the reduction of fronto-central high beta activity were analyzed quantitatively through their link with subjective and EEG-NF regulation success.

Results

The following eight categories, ordered by frequency in descending order, were found: "Behavior," "Imagination," "Emotion," "Distraction," "Thought," "Concentration," "Self-Talk" and "No Strategy." Linear mixed models revealed "Imagination," "Behavior," and "Thought" strategies as positive predictors of EEG-NF regulation success (defined as high beta activity during regulation beneath the baseline), and "Concentration" as a negative predictor of subjective (i.e., self-reported) NF regulation success.

Discussion

In conclusion, our study offers a classification system that may be used in future studies assessing strategy use for regulating food-related responses in patients with BED and associated overweight/obesity, providing valuable information on potential benefits of specific strategies and transferability to situations outside the NF treatment.