Neurofeedback in ADHD: a single-blind randomized controlled trial

Abstract

Neurofeedback treatment has been demonstrated to reduce inattention, impulsivity and hyperactivity in children with attention deficit/hyperactivity disorder (ADHD). However, previous studies did not adequately control confounding variables or did not employ a randomized reinforcer-controlled design. This study addresses those methodological shortcomings by comparing the effects of the following two matched biofeedback training variants on the primary symptoms of ADHD: EEG neurofeedback (NF) aiming at theta/beta ratio reduction and EMG biofeedback (BF) aiming at forehead muscle relaxation. Thirty-five children with ADHD (26 boys, 9 girls; 6-14 years old) were randomly assigned to either the therapy group (NF; n = 18) or the control group (BF; n = 17). Treatment for both groups consisted of 30 sessions. Pre- and post-treatment assessment consisted of psychophysiological measures, behavioural rating scales completed by parents and teachers, as well as psychometric measures. Training effectively reduced theta/beta ratios and EMG levels in the NF and BF groups, respectively. Parents reported significant reductions in primary ADHD symptoms, and inattention improvements in the NF group were higher compared to the control intervention (BF, d (corr) = -.94). NF training also improved attention and reaction times on the psychometric measures. The results indicate that NF effectively reduced inattention symptoms on parent rating scales and reaction time in neuropsychological tests. However, regarding hyperactivity and impulsivity symptoms, the results imply that non-specific factors, such as behavioural contingencies, self-efficacy, structured learning environment and feed-forward processes, may also contribute to the positive behavioural effects induced by neurofeedback training.

Evidence-Based Information on the Clinical Use of Neurofeedback for ADHD

“…Several trials also evaluated the effect of NF on the EEG, and on learning EEG control during training. Frequency training NF compared to sham-NF has been found to effectively reduce Theta/Beta ratio during NF training and in a resting state baseline [18], and both SCP and frequency training can increase intentional control over brain electrical activity [38], although this may only hold for a subgroup of the ADHD children training with NF [45]. In a large randomized trial, the authors found SCP (when compared to CAST) to significantly decrease theta activity after training, and increase both participants capacity to modulate SCP, and Contingent Negative Variation (CNV) [54][55][56].…”

“…Almost unequivocally, uncontrolled within subjects' pre-to post-treatment analyses indicate positive results with medium-to-large effect sizes (ES) [16,18,21,35,[38][39][40][41][42][43][44][45][46][47].…”

“…Furthermore, in none of the studies, investigators were blind to the participant's group assignment and parents were not aware of it in only 2 studies. In addition, only 1 study [18] used a truly equivalent control group that received electromyogram (EMG) biofeedback as a kind of sham-NF. Other control conditions may be problematic because the "high-tech" environment associated with NF or biofeedback can enhance parents and children expectation about positive treatment results.…”

“…A summary of the findings from all sham-or EMGbiofeedback-controlled studies assessing efficacy of NF for ADHD can be found in Table 1. Four of these studies found no significant group differences [17][18][19][20], and 1 lacks between groups comparison [48]. Lofthouse et al's [14] review reports the findings of studies favoring NF in comparison to sham-NF [14], but unfortunately these studies were not published in peer-reviewed journals.…”

“…As scientific production on NF is growing every year, a considerable amount of data was not included in these 2 reviews. Only during the end of 2010, 2011, and 2012, there were 6 other randomized controlled studies that were published [10,[17][18][19][20][21], with 3 of them using sham-NF as a control group [17,19,20]. Another review covers more recent literature, but it is only available in German [22].…”