Neurofeedback: One of today's techniques in psychiatry?

Abstract

Objectives

Neurofeedback is a technique that aims to teach a subject to regulate a brain parameter measured by a technical interface to modulate his/her related brain and cognitive activities. However, the use of neurofeedback as a therapeutic tool for psychiatric disorders remains controversial. The aim of this review is to summarize and to comment the level of evidence of electroencephalogram (EEG) neurofeedback and real-time functional magnetic resonance imaging (fMRI) neurofeedback for therapeutic application in psychiatry.

Method

Literature on neurofeedback and mental disorders but also on brain computer interfaces (BCI) used in the field of neurocognitive science has been considered by the group of expert of the Neurofeedback evaluation & training (NExT) section of the French Association of biological psychiatry and neuropsychopharmacology (AFPBN).

Results

Results show a potential efficacy of EEG-neurofeedback in the treatment of attentional-deficit/hyperactivity disorder (ADHD) in children, even if this is still debated. For other mental disorders, there is too limited research to warrant the use of EEG-neurofeedback in clinical practice. Regarding fMRI neurofeedback, the level of evidence remains too weak, for now, to justify clinical use. The literature review highlights various unclear points, such as indications (psychiatric disorders, pathophysiologic rationale), protocols (brain signals targeted, learning characteristics) and techniques (EEG, fMRI, signal processing).

Conclusion

The field of neurofeedback involves psychiatrists, neurophysiologists and researchers in the field of brain computer interfaces. Future studies should determine the criteria for optimizing neurofeedback sessions. A better understanding of the learning processes underpinning neurofeedback could be a key element to develop the use of this technique in clinical practice.

Résumé

Introduction

Le neurofeedback consiste à mesurer, chez un sujet, une activité cérébrale et à traiter le signal au moyen d’une interface technique afin d’en extraire un paramètre d’intérêt qui sera présenté en temps réel au participant sous la forme d’une information visuelle ou auditive. L’objectif est d’apprendre au sujet à modifier ce paramètre et donc à moduler son activité cérébrale et cognitive. Cependant, l’utilisation du neurofeedback en pratique clinique pour la prise en charge des troubles psychiatriques reste controversée.

Méthode

Cet article présente une synthèse de la 1^re journée nationale sur le neurofeedback organisé par la section Neurofeedback Evaluation & Training (NExT) de l’Association française de psychiatrie biologique et de neuropharmacologie (AFPBN). Un état des lieux de l’utilisation du neurofeedback en électroencéphalographie (EEG) et en imagerie par résonance magnétique fonctionnelle (IRMf) est proposé. Pour intégrer l’arsenal thérapeutique, cette technique doit en effet répondre aux exigences de l’evidence based medicine.

Résultats

Les études montrent une efficacité probable du neurofeedback en EEG pour le trouble du déficit de l’attention/hyperactivité (TDAH) chez les enfants. Pour les autres troubles psychiatriques, le nombre d’études est encore trop limité pour se positionner. En ce qui concerne le neurofeedback en IRMf, le niveau de preuve reste, pour l’heure, trop faible pour justifier une utilisation clinique. Les modalités d’emploi du neurofeedback, notamment en ce qui concerne les indications médicales, les protocoles d’utilisation (activité(s) cérébrale(s) ciblée(s), caractéristiques d’apprentissage) et les outils de mesure employés (EEG, IRMf, mode de traitement du signal) restent donc à clarifier.

Conclusion

Le vaste champ de recherche du neurofeedback implique à la fois des psychiatres, des neurophysiologistes et des chercheurs du domaine des interfaces cerveaux-ordinateurs. Les futurs travaux devront s’attacher à déterminer les critères permettant d’optimiser les séances de neurofeedback afin de mieux comprendre ses effets, le tout dans l’optique d’une utilisation en pratique clinique dans certaines indications. L’étude des processus d’apprentissage constitue un élément clé autour duquel les futures recherches devront se focaliser.

Introduction

Neurofeedback can be considered as a biofeedback technique (i.e. a technique which consists in measuring a physiological activity using a technical interface to extract a parameter of interest; this parameter is then presented in real-time to the participant, typically via visual or auditory feedback [1]; the goal is to teach the subject to modify the parameter). When the physiological activity is a brain activity, biofeedback is called neurofeedback. Thus, neurofeedback allows the subject to voluntary modulate his/her related brain and cognitive activities [1], [2] (Fig. 1).

The first observation of neurofeedback, was based on the classical conditioning principles applied to the electroencephalogram (EEG). Classical conditioning involves learning new behaviors through the process of association. Neurofeedback originates from the 1930s based on the work of Gustave Durup and Alfred Fessard, who were two emblematic figures of psychophysiology and neurophysiology in France. They observed that brain activity (alpha blocking response) could be modified according to the classical conditioning principles (i.e. to develop an association between an EEG activity (alpha blocking response), a behavior and cognitive response, and a signal of feedback [3]. In 1941, Jasper & Shagass published the first systematic study that investigated classical conditioning of EEG [4]. Subsequent studies in the 1960s confirmed that alpha blocking could indeed be conditioned and related to some specific cognitive activities of the trained subject [5].

After a serious decline during the 1980s and 1990s, mainly due to the poor reliability of methods used for recording brain activity, the technique gained ground again in the early 2000s with a renewed interest both in scientific and societal terms [6]. Thanks to the principle on which it is based and to the fertile dynamic nature of ongoing research in a range of clinical, therapeutic and fundamental topics, neurofeedback can be considered a technology of today [6], [7]. However, despite great interest in neurofeedback research [8], [9], [10], significant controversy exists, particularly in psychiatry and neurology [7], [11]. With regard to the efficacy of neurofeedback in brain disorders, opinions within the scientific community appear to be rather sharply divided [7], [9], [12] comprising an optimistic group who consider neurofeedback to be effective and a skeptical group who do neither assign scientific or therapeutic value to neurofeedback training. This article aims to review the evidence of EEG neurofeedback (EEG-NF) and real-time functional magnetic resonance imaging neurofeedback (fMRI-NF) in psychiatric disorders. The advantages and pitfalls for each of both neurofeedback techniques are discussed, and new perspectives are highlighted. Lastly, research on the learning process through the link between neurofeedback and brain computer interfaces (BCIs) is discussed.