Alpha power increases spontaneously during a neurofeedback session
Communications Psychology
Jacob Maaz *, Laurent Waroquier, Alexandra Dia *, Véronique Paban * & Arnaud Rey *
Jacob MAAZ, Alexandra DIA & Arnaud REY - Equipe MemoPsy
Jacob MAAZ & Véronique PABAN - Equipe RéadApt2C
Abstract
Electroencephalographic neurofeedback (EEG-NF) has been proposed as a promising technique to modulate brain activity through real-time EEG-based feedback. Alpha neurofeedback in particular is believed to induce rapid self-regulation of brain rhythms, with applications in cognitive enhancement and clinical treatment. However, whether this modulation reflects specific volitional control or non-specific influences remains unresolved. In a preregistered, double-blind, sham-controlled study, we evaluated alpha upregulation in healthy participants receiving either genuine (n = 30) or sham (n = 30) EEG-NF during a single-session design. A third arm composed of a passive control group (n = 32) was also included to differentiate between non-specific influences related or not to the active engagement in EEG-NF. Throughout the session, alpha power increased robustly, yet independently of feedback veracity, engagement in self-regulation, or feedback update frequency. Parallel increases in theta and sensorimotor rhythms further suggest broadband non-specific modulation. Importantly, these results challenge the foundational assumption of EEG-NF: that feedback enables volitional EEG control. Instead, they point to spontaneous repetition-related processes as primary drivers, calling for a critical reassessment of neurofeedback efficacy and its underlying mechanisms.
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Spontaneous Modulation of Alpha Power During a Neurofeedback Session Without Instructions
Psychophysiology
Jacob Maaz, Véronique Paban, Laurent Waroquier, Arnaud Rey
ABSTRACT
Electroencephalographic neurofeedback (EEG-NF) enables individuals to self-regulate specific EEG features with real-time sensory feedback. Despite clinical and cognitive-enhancement applications, the mechanisms underlying the EEG modulation remain poorly understood. Particularly, alpha activity (8–12 Hz) upregulation may occur independently of the participants' volitional control. We previously reported spontaneous increases in alpha power during a passive neurofeedback-like task using pre-recorded EEG feedback. In the present study, we replicated this protocol while implementing an EEG-NF procedure using real-time alpha power. Thirty-two healthy adults observed a gray circle whose size was either fixed (control) or continuously updated at 1, 5 or 10 Hz (experimental conditions). Importantly, participants were not informed of the nature of the feedback and received no instructions for self-regulation. We evaluated the effects of (i) trial repetition, (ii) the presence (control vs. experimental conditions), (iii) the frequency (1, 5 or 10 Hz) and (iv) the source (online vs. offline alpha) of feedback update on EEG features classically targeted by EEG-NF. Importantly, we observed robust increases in alpha power over time independently of the presence, frequency and source of feedback update. The presence, frequency and source of feedback update did not influence the EEG features considered. These findings suggest that alpha EEG-NF upregulation may arise from spontaneous dynamics, such as time-on-task effects, rather than the hypothesized self-regulation mechanism. The assumption that observed alpha increases reflect successful neurofeedback learning is thus called into question. More broadly, the present study highlights the importance of including control conditions and accounting for non-specific effects when evaluating EEG-NF outcomes.