Atypical Functional Brain Regions Identification in Children with Autism Spectrum Disorder Using One-Class SVM and fMRI-Derived Graph-Theoretic Parameters

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that typically emerges in early childhood and persists throughout life, making early and objective detection crucial. This study integrates graph theoretic approach with anomaly detection approaches to identify atypical functional brain regions in children aged up to 5 years with ASD. Resting-state fMRI data of 53 ASD and 53 healthy subjects were used to construct functional connectivity matrices were across 32 functional regions of interest, from which graph theoretic features were extracted. The one-class SVM achieved an AUC of 0.733 in identifying atypical regions. Atypicality was observed in the salience network , specifically, in the supramarginal gyrus, anterior cingulate cortex and left anterior insula. In the visual network, medial occipital and laterl occipital regions were identified as atypical. The language network showed atypical regions in the right inferior frontal gyrus and the left posterior superior temporal gyrus. The dorsal attention network exhibited atypicality in the right frontal eye field region. Graph-theoretic analysis to regional atypicality highlighted disruptions in integration, segregation, and hub-related characteristics.