EEG coherence and symptom profiles of children with Attention-Deficit/Hyperactivity Disorder

Objective: We compared EEG coherence in children with and without AD/HD, and sought to relate observed anomalies to AD/HD symptoms. Methods: Forty children with AD/HD and 40 age-and sex-matched controls had eyes-closed resting EEG coherence calculated for eight interhemispheric electrode pairs and eight intrahemispheric pairs (four within each hemisphere) in the delta, theta, alpha, beta and "40 Hz" gamma bands. Results: At short-medium inter-electrode distances, the AD/HD group had increased intrahemispheric coherence in delta and theta, and reduced (L > R) laterality in delta, alpha, beta and gamma. Over longer inter-electrode distances, the AD/HD group had reduced intrahemispheric coherence in alpha. In interhemispheric comparisons, the AD/HD group had reduced frontal coherence in delta, alpha and gamma, increased temporal theta and reduced temporal alpha coherences, and increased central/parietal/occipital coherence in theta. Smaller left-lateralized coherences in AD/HD correlated negatively with DSM Inattentive and DSM Total scores, and smaller frontal interhemispheric coherence in alpha correlated negatively with DSM Hyperactive/Impulsive score. Conclusions: The negative correlations between AD/HD coherence anomalies and symptoms suggest that several anomalies reflect compensatory brain function. Significance: Coherence differences in AD/HD may reflect anomalous frontal right-hemisphere linkages that help compensate functional brain anomalies in the left frontal regions in this disorder. (C) 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.