Quantitative EEG Ratios and Power in Children with Autistic Spectrum Disorder

Background: Autism Spectrum Disorder (ASD) has been defined as is a neurodevelopmental disorder with associated deficits in executive function, emotional, language and social function. Objective: The current study aimed to study the quantitative EEG findings in autistic children and compare it to normal control. Methods: QEEG recording was done for 21 children with ASD (aged 4-12 years) and compared to 21 matched controls during an open-eyes condition. All subjects were further divided into a younger children subgroup (4-8 years) and an older children subgroup (8-12 years) to determine if age influences the QEEG results. The absolute and relative powers of delta, theta, alpha and beta frequency bands, as well as theta/beta and delta/alpha ratios were calculated. Results: The absolute delta and absolute and relative theta bands were greater in power in frontal, central and posterior regions in 4-8 years old, where the absolute delta and theta power were reduced only in Cz in 8-12 years compared to age matched control group. Also the relative alpha power showed the reduced power across the entire scalp with more prominent in 4-8 years old age group. As regarding the relative EEG power of beta band, it was significantly different in frontal region with no significant difference regarding delta, theta and alpha bands between patients and control group in 8-12 years old. The delta alpha ratio was higher in ASD patients compared to controls but the theta/beta ratio was similar in both groups. The increase in delta alpha ratio remained significant in the younger subgroup but disappeared in the older subgroup. Conclusion: QEEG measures are sensitive to the neuropathological involvement and maturation of ASD children. The delta alpha ratio emerges as an important characteristic requiring further research to determine its utility as marker of ASD in young children. QEEG studies can contribute to a more comprehensive understanding of ASD and to the discovery of potential biomarkers that can aid with its diagnosis and management.