Electrophysiological evaluation of cognitive intervention outcomes in children with attention deficit/hyperactivity disorder

Introduction: Attention deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders in children and adolescents, with an estimated global prevalence ranging from approximately 5-8%. ADHD has been associated with alterations in brain structure and function. Cognitive interventions are frequently implemented in children with ADHD, and electroencephalography (EEG) is commonly used to examine neural activity in this population. The present study describes resting-state EEG characteristics in children with ADHD before (pre) and after (post) a 3-month period of cognitive intervention, focusing exclusively on electrophysiological measures. Methods: A total of 55 children with ADHD aged 7-11 years (13 girls and 42 boys, predominantly inattentive subtype) participated in the study. Resting-state EEG was recorded pre and post a 3-month cognitive intervention. The quantitative EEG spectral analysis paradigm was performed to examine absolute power in delta, theta, alpha, and beta frequency bands, as well as the theta/beta ratio (TBR), across frontal, central, and parietal regions. All electrophysiological measures were statistically compared between pre- and post-recordings. Results: Background activity was diffuse, disorganized, and heterogeneous in both pre- and post-EEG. Resting-state EEG demonstrated elevated low-frequency activity and increased TBR across frontal, central, and parietal cortical regions, consistent with commonly reported electrophysiological patterns in ADHD. No significant pre-post differences were observed in absolute power spectra or TBR across recording conditions or cortical regions. Additionally, elevation of frontal alpha was observed under open-eyes conditions. Conclusion: Two possible explanations may account for the absence of observable changes in the typical ADHD EEG profile, characterized by elevated low-frequency power and accompanied by increased theta/beta ratio across frontal, central, and parietal regions. A 3-month observation period might not be optimal to produce changes in neurophysiological measures detectable on EEG. Ongoing developmental processes may contribute to variability in cortical organization, potentially obscuring subtle temporal changes in EEG measures. Additionally, the observed elevation of frontal alpha activity may reflect broader neurophysiological variability rather than solely delayed cortical maturation. Future research may help clarify the neurobiological links between longitudinal EEG dynamics and functional developmental trajectories to identify potential neurophysiological biomarkers in children with ADHD.