High-order alpha-band network reorganization underpins clinical symptom alleviation following EEG neurofeedback in preschool children with autism spectrum disorder: a multidimensional study.

BACKGROUND

Autism Spectrum Disorder (ASD) is increasingly recognized as a disorder of neural connectivity and network architecture. While EEG neurofeedback (NFB) has shown clinical efficacy in ameliorating ASD symptoms, the underlying neurophysiological mechanisms-specifically regarding high-order network reorganization beyond simple power spectrum changes-remain poorly understood. Furthermore, there is a need to validate whether robust biomarkers can be identified using low-density EEG systems suitable for preschool children.

METHODS

In this randomized, sham-controlled trial, 40 preschool children with ASD (mean age 5.56 years) were assigned to either an active NFB group (n = 20) or a sham-control group (n = 20). The experimental group underwent a 4-week alpha-band NFB training protocol using an 8-channel portable EEG system. We employed a multidimensional analytical framework integrating High-Order Functional Connectivity (HOFC), dynamic Network State Entropy (NSE), and cross-frequency interaction analysis to characterize neural reorganization. Clinical improvements were assessed using the Autism Behavior Checklist (ABC).

RESULTS

The NFB group exhibited significant reductions in ABC total scores and Social Relating subscale scores. Neurophysiologically, while conventional Low-Order Functional Connectivity (LOFC) failed to capture significant global changes, the alpha-band HOFC revealed a systemic optimization toward a more efficient small-world architecture, characterized by increased Clustering Coefficient (CC) and Local Efficiency (LE), and decreased Characteristic Path Length (CPL). Additionally, NSE analysis indicated increased dynamic flexibility across multiple frequency bands, reflecting a reduction in neural rigidity. Crucially, the optimization of alpha-band HOFC metrics was significantly correlated with the degree of clinical symptom alleviation (r = 0.678, p = 0.015).

CONCLUSION

These findings demonstrate that alpha-band NFB facilitates clinical recovery in preschool children with ASD by inducing frequency-specific high-order network reorganization. The study suggests that alpha-band HOFC may serve as a potential exploratory electrophysiological correlate for monitoring therapeutic responses.