Selective neuromodulation induced by alpha-based neurofeedback learning: A double-blind randomized study

Background: The neuromodulation induced by neurofeedback training (NFT) remains a matter of debate. Investigating the modulation of brain activity specifically associated with NF requires controlling for multiple factors, such as reward, performance, congruency between task and targeted brain activity. This can be achieved using sham feedback (FB) control condition, equating all aspects of the experiment but the closed loop between brain activity and FB. Objective: We aimed at investigating the modulation of individual alpha EEG activity induced by NFT in a double-blind, randomized, sham-controlled study. Methods: Forty-eight healthy participants were assigned to either NF (n=25) or control (n=23) group and performed 12 NFT sessions of alpha upregulation with a wearable EEG device. Participants of the NF group received FB based on their individual alpha activity. The control group received the auditory FB of participants of the NF group. Results: An increase of alpha activity across training sessions was observed in the NF group only (p<0.001). This neuromodulation was selective in that it was not observed for theta (4-8Hz) and low beta (13-18Hz) activities. It was associated with an increased feeling of control (p<0.001), more marked for NF than control group. Anxiety level decreased and relaxation feeling increased with training in both groups. Conclusions: NFT across multiple sessions can induce specific brain modulation, suggesting a neuroplasticity selective of the targeted brain activity. Our results pave the way to self-learnt, NF-based neuromodulation with light-weighted, wearable EEG systems for various applications (e.g. epilepsy, sleep, attention).