Qualitative EEG abnormalities signal a shift towards inhibition-dominated brain networks. Results from the EU-AIMS LEAP studies

Juarez-Martinez, E. L.; Avramiea, A.-E.; Garces, P.; Hipp, J. F.; Poil, S.-S.; Diachenko, M.; Mansvelder, H.; Jones, E. J.; Mason, L.; Murphy, D.; Loth, E.; Oakley, B.; Charman, T.; Banaschewski, T.; Oranje, B.; Buitelaar, J.; Bruining, H.; Linkenkaer-Hansen, K.

doi:10.1101/2024.09.19.613847

bioRxiv · 10.1101/2024.09.19.613847

Qualitative EEG abnormalities signal a shift towards inhibition-dominated brain networks. Results from the EU-AIMS LEAP studies

Juarez-Martinez, E. L.·Avramiea, A.-E.·Garces, P.·Hipp, J. F.·Poil, S.-S.·Diachenko, M.·Mansvelder, H.·Jones, E. J.·Mason, L.·Murphy, D.·Loth, E.·Oakley, B.·Charman, T.·Banaschewski, T.·Oranje, B.·Buitelaar, J.·Bruining, H.·Linkenkaer-Hansen, K.

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Abstract

Qualitative EEG abnormalities are common in Autism Spectrum Disorder (ASD) and hypothesized to reflect disrupted excitation/inhibition balance. To test this, we recently introduced a functional measure of network-level E/I ratio (fE/I). Here, we applied fE/I and other EEG measures to alpha oscillations from source-reconstructed data in the EU-AIMS dataset (267 ASD, 209 controls). We analyzed these measures alongside qualitative EEG abnormalities ranging from slowing of activity to epileptiform patterns, aiming to replicate the findings from the SPACE-BAMBI study. EEG abnormalities were rare in adults and could not be statistically assessed. ASD children-adolescents with EEG abnormalities exhibited lower relative alpha power and fE/I compared to those without. However, EEG-abnormality scoring did not stratify the behavioral heterogeneity of ASD using clinical measures. Surprisingly, several controls also exhibited qualitative EEG abnormalities with a strikingly similar anatomical distribution of reduced fE/I, suggesting a shift towards inhibition-dominated network dynamics in sensory processing regions. The robustness of this association between EEG abnormalities and reduced fE/I was further supported by re-analysis of the SPACE-BAMBI study in source space. Stratification by the presence of EEG abnormalities and their effects on network activity may help understand neurodevelopmental physiological heterogeneity and the difficulties in implementing E/I targeting treatments in unselected cohorts.

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Juarez-Martinez, E. L., Avramiea, A.-E., Garces, P., Hipp, J. F., Poil, S.-S., Diachenko, M., Mansvelder, H., Jones, E. J., Mason, L., Murphy, D., Loth, E., Oakley, B., Charman, T., Banaschewski, T., Oranje, B., Buitelaar, J., Bruining, H., Linkenkaer-Hansen, K.. 2024-09-21. Qualitative EEG abnormalities signal a shift towards inhibition-dominated brain networks. Results from the EU-AIMS LEAP studies. https://doi.org/10.1101/2024.09.19.613847

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