Introduction

The techniques of neurofeedback (NF) enable a patient to train him or herself to self-regulate a single measure of brain activity, which can be measured through EEG. EEG-NF (EEG and neurofeedback) training aims to achieve self-control over specific aspects of electrical brain activity through real-time feedback and positive reinforcement and implement these self-regulation skills in daily life. The aim of this study was to focus on recent major developments in the field of NF and ADHD. 

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) recommendations are used  to undertake the search and analysis of the international scientific literature. Studies were included if they met the following criteria:

1. Design: randomized controlled trials (RCT).
2. Intervention: standard protocol EEG-NF with Theta/Beta Ratio training—TBR (or likely to standard TBR training) or Slow Cortical Potentials (SCP) training.
3. Control group: semi-active (i.e., cognitive remediation and EMG-biofeedback) and sham-NF.
4. Participants: participants with an established clinical diagnosis of ADHD thanks to DSM or CIM criteria.
5. Evaluation of ADHD severity based on a validated scale with probably blinded assessment (teacher assessment) data available.
6. No secondary analyses of previously included trials.

Results

Results of the literature search

Five identified studies met the eligibility criteria.

Results of the meta-analysis

Studies and Population characteristics

263 patients with ADHD were included, 146 patients were trained with EEG-NF.

Effects of EEG-NF on parent assessment (probably no-blinded assessment)

On parent assessment (probably unblinded assessment), the overall ADHD score (SMD = −0.49 [−0.74, −0.24]), the inattention score (SMD = −0.46 [−0.76, −0.15]) and the hyperactivity/impulsivity score (SMD = −0.34 [−0.59, −0.09]) were significantly improved in patients receiving EEG-NF compared to controls.

Effect of EEG-NF on teacher assessment (probably blinded assessment)

On teacher assessment (probably blinded assessment), only the inattention score was significantly improved in patients receiving EEG-NF compared to controls (SMD = −0.30 [−0.58, −0.03]).

Sensitivity analysis to test for medication effects

A significant correlation was found between the ES on the overall ADHD score assessed by teacher and percentage of patient treated with methylphenidate (rs[5] = 0.9, p = 0.037).

Discussion

This meta-analysis of EEG-NF in children with ADHD highlights improvement in the inattention dimension of ADHD symptoms. Future investigations should pay greater attention to adequately blinded studies and EEG-NF protocols that carefully control the implementation and embedding of training.