Resting state EEG power spectrum and functional connectivity in autism: a cross-sectional analysis
Authors: Garcés Pilar , Baumeister Sarah , Mason Luke , Chatham Christopher H. , Holiga Stefan , Dukart Juergen , Jones Emily J. H. , Banaschewski Tobias , Baron-Cohen Simon , Bölte Sven , Buitelaar Jan K. , Durston Sarah , Oranje Bob , Persico Antonio M. , Beckmann Christian F. , Bougeron Thomas , Dell’Acqua Flavio , Ecker Christine , Moessnang Carolin , Charman Tony , Tillmann Julian , Murphy Declan G. M. , Johnson Mark , Loth Eva , Brandeis Daniel , Hipp Joerg F. ,   The EU-AIMS LEAP group authorship, Ahmad Jumana , Ambrosino Sara , Auyeung Bonnie , Banaschewski Tobias , Baron-Cohen Simon , Baumeister Sarah , Beckmann Christian F. , Bölte Sven , Bourgeron Thomas , Bours Carsten , Brammer Michael , Brandeis Daniel , Brogna Claudia , de Bruijn Yvette , Buitelaar Jan K. , Chakrabarti Bhismadev , Charman Tony , Cornelissen Ineke , Crawley Daisy , Dell’Acqua Flavio , Dumas Guillaume , Durston Sarah , Ecker Christine , Faulkner Jessica , Frouin Vincent , Garcés Pilar , Goyard David , Ham Lindsay , Hayward Hannah , Hipp Joerg , Holt Rosemary , Johnson Mark H. , Jones Emily J. H. , Kundu Prantik , Lai Meng-Chuan , ardhuy Xavier Liogier D’ , Lombardo Michael V. , Loth Eva , Lythgoe David J. , Mandl René , Marquand Andre , Mason Luke , Mennes Maarten , Meyer-Lindenberg Andreas , Moessnang Carolin , Mueller Nico , Murphy Declan G. M. , Oakley Bethany , O’Dwyer Laurence , Oldehinkel Marianne , Oranje Bob , Pandina Gahan , Persico Antonio M. , Ruggeri Barbara , Ruigrok Amber , Sabet Jessica , Sacco Roberto , Cáceres Antonia San José , Simonoff Emily , Spooren Will , Tillmann Julian , Toro Roberto , Tost Heike , Waldman Jack , Williams Steve C. R. , Wooldridge Caroline , Zwiers Marcel P. 
Published: May 2022

Background

Understanding the development of the neuronal circuitry underlying autism spectrum disorder (ASD) is critical to shed light into its etiology and for the development of treatment options. Resting state EEG provides a window into spontaneous local and long-range neuronal synchronization and has been investigated in many ASD studies, but results are inconsistent. Unbiased investigation in large and comprehensive samples focusing on replicability is needed.

Methods

We quantified resting state EEG alpha peak metrics, power spectrum (PS, 2–32 Hz) and functional connectivity (FC) in 411 children, adolescents and adults (n = 212 ASD,n = 199 neurotypicals [NT], all with IQ > 75). We performed analyses in source-space using individual head models derived from the participants’ MRIs. We tested for differences in mean and variance between the ASD and NT groups for both PS and FC using linear mixed effects models accounting for age, sex, IQ and site effects. Then, we used machine learning to assess whether a multivariate combination of EEG features could better separate ASD and NT participants. All analyses were embedded within a train-validation approach (70%–30% split).

Results

In the training dataset, we found an interaction between age and group for the reactivity to eye opening (p = .042 uncorrected), and a significant but weak multivariate ASD vs. NT classification performance for PS and FC (sensitivity 0.52–0.62, specificity 0.59–0.73). None of these findings replicated significantly in the validation dataset, although the effect size in the validation dataset overlapped with the prediction interval from the training dataset.

Limitations

The statistical power to detect weak effects—of the magnitude of those found in the training dataset—in the validation dataset is small, and we cannot fully conclude on the reproducibility of the training dataset’s effects.

Conclusions

This suggests that PS and FC values in ASD and NT have a strong overlap, and that differences between both groups (in both mean and variance) have, at best, a small effect size. Larger studies would be needed to investigate and replicate such potential effects.