Cortical Hypoactivation of Frontal Areas Modulates Resting Electroencephalography Microstates in Children With Attention-Deficit/Hyperactivity Disorder.

Abstract

Background: In the current study, we examined electroencephalography (EEG) microstate alterations and their neural generators during resting state in children with attention-deficit/hyperactivity disorder (ADHD) to explore a potential state biomarker.

Methods: A total of 76 participants, 38 with combined-type ADHD and 38 neurotypical children, took part in the study. Five-minute resting (eyes-open) 128 channel EEG data were acquired, and 2 minutes of clean EEG data were analyzed for microstates, its sources, and connectivity in both groups. Between-groups comparisons were done for microstate parameters using modified k-means clustering with Cartool software. Furthermore, the cortical sources and functional connectivity of significant microstate maps were explored using LORETA software. Subsequently microstate parameters were correlated with the behavioral scores from the Conners' Parent Rating Scale.

Results: Among the microstate parameters examined, children with ADHD displayed significant differences (p < .05) in time frames and time coverage of map B (decreased) and transition probability of map D (increased). Interestingly, source analysis of both microstate maps showed hypoactivation of frontal areas predominantly while functional connectivity showed hyperconnectivity between the medial frontal gyrus and anterior cingulate gyrus (executive function area) for map B and hypoconnectivity between the medial frontal gyrus and middle temporal gyrus (both are suggested to be part of default mode network areas) for map D. Further, cross-spectral density values of map B were found to be correlated with executive function scores from the Conners' questionnaire.

Conclusions: EEG microstate features, together with source and connectivity measures, could help differentiate children with ADHD from neurotypical children. The hypoactivation of predominantly frontal areas and their connectivity was found to determine microstate maps.