Beyond Theta-Beta Ratio: EEG Microstate D as a Target for ADHD Neurofeedback

511 

Abstract Submission 

Victor Férat¹, Marie-Pierre Deiber^2,3, Roland Hasler², Nader Perroud^2,3, Christoph Michel^1,4, Tomas Ros^1,4

¹Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, Geneva, Switzerland, ²Department of Psychiatry, Faculty of Medicine, University of Geneva, Geneva, Switzerland, ³Division of Psychiatric Specialties, Department of Psychiatry, University Hospitals of Geneva, Geneva, Switzerland, ⁴Center for Biomedical Imaging, Lausanne, Switzerland

Victor Férat  
Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences
Geneva, Switzerland

Marie-Pierre Deiber  
Department of Psychiatry, Faculty of Medicine, University of Geneva|Division of Psychiatric Specialties, Department of Psychiatry, University Hospitals of Geneva
Geneva, Switzerland|Geneva, Switzerland

Roland Hasler  
Department of Psychiatry, Faculty of Medicine, University of Geneva
Geneva, Switzerland

Nader Perroud  
Department of Psychiatry, Faculty of Medicine, University of Geneva|Division of Psychiatric Specialties, Department of Psychiatry, University Hospitals of Geneva
Geneva, Switzerland|Geneva, Switzerland

Christoph Michel  
Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences|Center for Biomedical Imaging
Geneva, Switzerland|Lausanne, Switzerland

Tomas Ros  
Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences|Center for Biomedical Imaging
Geneva, Switzerland|Lausanne, Switzerland

Attention-Deficit/Hyperactivity Disorder (ADHD) is a mental disorder marked by persistent inattention, hyperactivity, and impulsivity, significantly impacting daily life. First-line treatments, like psychostimulants, though effective, come with side effects, leading some to seek alternatives for long-term remission. Neurofeedback (NFB), allowing self-regulation of neurophysiology, stands out.
NFB, especially Theta-Beta ratio (TBR)-based protocols, has been common for ADHD. However, recent studies (Arns et al., 2018) challenge TBR's consistency in ADHD diagnosis, supported by a meta-analysis (Arns, 2014). This highlights the need for exploring new diagnostic and treatment markers. In a recent study (Férat et al., 2022a), EEG microstate analysis (Michel, 2018) emerged as a novel framework, revealing increased microstate D presence in ADHD individuals.

Building on this, our study explores EEG microstate (Hernandez, 2015) D as a potential therapy for ADHD individuals. This research promises to enhance understanding and offer alternative, potentially more effective approaches in managing ADHD symptoms through neurofeedback interventions tailored to specific neurophysiological markers.

In this clinical study, a crossover design was employed. 19 participants with ADHD underwent two randomly ordered neurofeedback sessions, one aiming to increase microstate D and the other to decrease it. Comprehensive clinical assessments, self-report questionnaires, resting-state EEG recordings, and continuous performance tasks were administered before and after each neurofeedback session.

EEG was continuously recorded throughout the 2 neurofeedback sessions using a 64 electrode cap.The five grand average EEG microstate topographies obtained from dataset 2 of Férat et al. 2022 (Férat et al., 2022a) were used as template to estimate in real time the coverage of microstate D. A score was estimated by comparing the real-time value to the one at rest. A visual feedback consisting of a rectangular gauge placed horizontally in the center of the screen was used to inform participants. When the feedback value was negative, the gauge filled linearly to the left, gradually filling completely for a feedback value of -1. Similarly, when the feedback value was positive, the gauge filled to the right, gradually filling completely for a feedback value of 1.

Among the twenty individuals with ADHD enrolled, two dropped out before the neurofeedback sessions. After artifact rejection, data from 16 participants for the up-regulation session, 13 for the down-regulation session, and 12 for the comparative analysis of both were analyzed. During the up-regulation phase, a significant increase in the presence of microstate D was observed compared to baseline. However, no significant differences were found during the down-regulation phase. When comparing the two phases, a trend suggested the specificity of the neurofeedback protocol, with neurofeedback-specific effects observed. In addition, during each execution of the continuous performance task, an increase in the presence of microstate D was observed, regardless of the neurofeedback direction. No adverse effects were reported throughout the study.

These findings suggest that neurofeedback targeting microstate D does not induce significant adverse effects. The exclusion of some subjects highlights the technical intricacies of microstate neurofeedback, which heavily relies online data quality. The non-specific results indicate the efficacy of the protocol in increasing the presence of microstate D in individuals with ADHD but less effectiveness in reducing it. The analyses underscore the potential specificity of microstate neurofeedback, with distinctions between up-regulation and down- regulation sessions. Moreover, the increased presence of microstate D during continuous performance tasks supports the existing literature on its association with attentional functions in the human brain.

Psychiatric (eg. Depression, Anxiety, Schizophrenia) ¹

EEG/MEG Modeling and Analysis

EEG ²

Attention: Visual

ADULTS

Attention Deficit Disorder

Data analysis

Electroencephaolography (EEG)

Experimental Design

Psychiatric Disorders

Therapy

Other - Neurofeedback