Changes in EEG Spectrograms, Event-Related Potentials and Event- Related Desynchronization Induced by Relative Beta Training in ADHD Children

Abstract

Background. During the last three decades EEG-based biofeedback (neurofeedback) was used as an alternative treatment for reducing symptoms of ADHD. The goal of this study was to objectively assess the efficacy of biofeedback training by comparing spectrograms, ERPs and ERDs, measured before and after 20 sessions of neurotherapy in a group of ADHD children. Method. Electroencephalogram (EEG), Event related potentials (ERPs) and event related synchronisation/desynchronisation (ERD/ERS) were recorded and computed in auditory GO/NOGO task before and after 15-22 sessions of EEG biofeedback. Eighty-six ADHD children participated in the study. Each session consisted of 30 min of relative beta training. The patients were divided into two groups (good performers and poor performers) depending on their ability to elevate beta activity during sessions. Results. Amplitude of late positive components of evoked potentials in response to NOGO stimuli increased, and event-related synchronisation in alpha frequency band measured at central areas decreased after the whole set of sessions of neurofeedback training in the group of good performers but did not change for the poor performers group. Evoked potential differences between post- and pre-treatment conditions for good performers were distributed over frontal-central areas, reflecting activation of frontal cortical areas associated with beta training. Conclusion. Relative beta training with electrodes located above the frontal areas was associated with an increase of the late positive NOGO component. This activation likely indicates recovery of normal functioning of the executive system.