Measurement of Excitation-Inhibition Imbalance in Autism spectrum Disorder Using EEG Proxy Markers: A Pilot Study

Autism Spectrum Disorder (ASD) is a severe neurodevelopmental disorder characterized primarily by social impairments and repetitive behaviors. Imbalance in excitatory-inhibitory (E/I) activity within the central nervous system may be a key mechanism underlying ASD. Electroencephalography (EEG) is a useful tool for recording brain electrical signals, reflecting the activity of cortical neuron populations, and estimating both global and regional E/I balance. Various EEG methods can estimate E/I balance, including non-periodic exponent, corrected alpha power, sample entropy, average spatial phase synchronization (ASPS), and detrended fluctuation analysis (DFA) based on E/I indices. However, research on using EEG proxy markers to assess E/I imbalance in autism is limited, and there is no study indicating which method is most sensitive. Therefore, this study employed a high-density EEG acquisition system to collect data from a relatively large sample of autistic and typically developing (TD) children. We computed EEG proxy markers and used the Coefficient of Variation (CV) to compare the sensitivity of five EEG markers between the two groups. The results indicated that non-periodic exponent based on power spectra and corrected alpha power from non-periodic neural activity were more advantageous. The findings may provide theoretical support for the exploration of EEG biomarkers based on E/I balance theory.