Phase-Amplitude Coupling Brain Networks in Children with Attention-Deficit/Hyperactivity Disorder

In cognitive neuroscience, there is an increasing interest in identifying and understanding the synchronization of distinct neural oscillations with different frequencies that might support dynamic communication within the brain. This study explored the cross-frequency phase-amplitude coupling brain network characteristics of resting-state electroencephalograms between 30 children with attention-deficit/hyperactivity disorder (ADHD) and 30 age-matched typically developing children. Compared with control group, children with ADHD show increased coupling intensity and altered distribution patterns of dominant paired channels, especially in the delta-gamma(H), theta-gamma(H), alpha-gamma(H), beta(L)-gamma(H), and beta(H)-gamma(H) coupling networks. Regarding graph theory properties, the characteristic path length, the mean clustering coefficient, the global efficiency, and the mean local efficiency significant difference in many cross-frequency coupling networks, especially in the delta-gamma(H), theta-gamma(H), alpha-gamma(H), beta(L)-gamma(H), and beta(H)-gamma(H) coupling networks. The area under the receiver operating characteristic curve (AUC) in low-frequency coupling with a high-gamma frequency was larger than that in coupling with low-gamma frequency (AUC values of delta-gamma(L), theta-gamma(L), alpha-gamma(L), beta(L)-gamma(L), beta(H)-gamma(L), delta-gamma(H), theta-gamma(H), alpha-gamma(H), beta(L)-gamma(H), and beta(H)-gamma(H) were 0.794, 0.722, 0.666, 0.570, 0.881, 0.992, 0.998, 0.998, 0.989, and 0.974, respectively). These findings demonstrate altered coupling intensity and disrupted topological organization of coupling networks, support the altered brain network theory in children with ADHD. The coupling intensity and graph theory properties of low-frequency coupling with high-gamma frequency were promising resting-state electroencephalogram biomarkers of ADHD in children.