Prevalence and patterns of video-EEG abnormalities in children with autism spectrum disorder: Age- and sex-specific findings from a large-scale cross-sectional study.

Children with autism spectrum disorder (ASD) commonly exhibit electroencephalographic (EEG) abnormalities, but age- and sex-related patterns of video-EEG (v-EEG) findings remain incompletely characterized. This retrospective cross-sectional study investigated v-EEG abnormalities in 761 children with ASD aged 1-17 years. All participants underwent at least 4 h of un-sedated v-EEG monitoring. The use of prolonged, un-sedated monitoring enhanced the sensitivity for detecting sleep-activated abnormalities and provided a more representative sample of physiological brain activity. Results revealed that 375 participants (49.3%) showed abnormal v-EEG findings. Frontal abnormalities were most frequent (154, 20.2%), followed by parietal abnormalities (119, 15.6%), temporal abnormalities (84, 11.0%), and occipital abnormalities (29, 3.8%); generalized abnormalities were observed in 241 participants (31.7%). The most common waveform abnormalities were sleep slow waves (255, 33.5%), spike waves (248, 32.6%), sharp waves (163, 21.4%), wakefulness slow waves (79, 10.4%), and spindle-wave abnormalities (68, 8.9%). Age was associated with v-EEG abnormality status: children aged 4-5.9 years showed the highest overall abnormality rate (64.5%) and elevated rates of several waveform and sleep-activated abnormality categories after Bonferroni correction. In contrast, sex-related differences were small and did not remain significant after correction; sex was not independently associated with overall v-EEG abnormality status after adjustment for age. These findings provide a descriptive characterization of age-related v-EEG abnormality patterns in a large clinical ASD cohort and support further prospective studies incorporating standardized clinical measures, comparison groups, and longitudinal follow-up.