Spectral insights: EEG feature and excitatory/ inhibitory balance in children with autism.

Autism Spectrum Disorder (ASD) involves diverse social communication impairments and repetitive behaviors, potentially linked to an imbalance in excitatory and inhibitory (E/l) neural activity. This study examines EEG data to explore the E/l balance in children with ASD and its relation to symptom severity. Using retrospective EEG data from children diagnosed with ASD, we applied spectral parameterization techniques, focusing on the aperiodic component of the EEG signals. The analysis employed the FOOOF (Fitting Oscillations & One-Over-F) model to examine the power-law function's exponent. Our sample included 97 children, categorized by the severity of their symptoms according to DSM-5 criteria. Results indicated a trend where increased EEG heterogeneity correlated with higher ASD severity, although the findings were not statistically significant. EEG anomalies, such as inconsistent hemispheric activity, abnormal slow waves, and paroxysmal bursts, were indicative of E/I imbalances. The prevalence of these anomalies increased with ASD severity: 53.8% of Level 1, 64.9% of Level 2, and 72.3% of Level 3 patients exhibited such anomalies Furthermore, higher severity levels exhibited significant increases in anomalies in the Frontal and Central regions, along with more prevalent diffuse patterns and anomalies in combination regions. These results suggest that both the aperiodic component and EEG anomalies could serve as biomarkers for ASD severity, highlighting the potential for more personalized diagnostic and therapeutic approaches.