Abstract Details

Title Using the Aperiodic Exponent from Resting-state Magnetoencephalography (MEG) to Assess Excitation/Inhibition (E/I) in Temporal Lobe Epilepsy Patients

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) P7 - Poster Session 7 (8:00 AM-9:00 AM)

Poster/Presentation
Number 10-008

Objective To assess excitation/inhibition (E/I) alterations in temporal lobe epilepsy (TLE) patients using resting-state magnetoencephalography (MEG) and explore the relationship between E/I and cortical thickness.

Background TLE, the most common form of focal epilepsy, involves recurrent seizures originating in the temporal lobe and is characterized by E/I imbalance and cortical thinning. Given the challenges of measuring E/I balance in vivo, a non-invasive measure of E/I would be valuable in patients with epilepsy and other excitability disorders. The aperiodic exponent of M/EEG signals, representing the brain’s background noise, is one such measure recently studied. A larger exponent suggests lower E/I, while a smaller exponent suggests higher E/I. The potential applications of this measure remain unknown in epilepsy and TLE, specifically.

Design/Methods MEG recordings and 3T MRI images were obtained from 32 TLE patients (17=left, 15=right) and 87 healthy controls at Montreal Neurological Institute-Hospital. Using Brainstorm and CAT12, head modelling and cortical thickness assessment was completed. MEG recordings were coregistered with MRI images to reconstruct six minutes of wakefulness resting state cortical activity. By applying FOOOF to the power-spectrum density of the MEG signals, we extracted the exponent of the aperiodic components. The aperiodic exponent and cortical thickness were modeled vertex-wise, and resulting maps were thresholded after cluster-based permutation statistics.

Results Compared to controls, the aperiodic exponent was broadly and significantly lower in TLE patients, indicating higher E/I, with largest differences in posterior head regions. Additionally, a thicker cortex was significantly associated with a larger exponent, or lower E/I, in widespread regions in healthy controls and to a greater extent in left TLE than right TLE.

Conclusions

This research demonstrates modulations in the aperiodic exponent in TLE patients that correlate with cortical thickness, supporting its potential as a non-invasive measure of E/I alterations in epilepsy. Future studies should further evaluate its translation into clinical practice.

Authors/Disclosures
Gurwinder Johal PRESENTER	Mr. Johal has nothing to disclose.
Giovanni Pellegrino, MD (S. Camillo Hospital)	Dr. Pellegrino has nothing to disclose.
Victoria Ros, MD	Dr. Ros has received personal compensation in the range of $0-$499 for serving on a Speakers Bureau for Jazz Pharmaceuticals. Dr. Ros has received personal compensation in the range of $0-$499 for serving on a Speakers Bureau for UCB.
Christophe Grova, PhD	Prof. Grova has nothing to disclose.
Eliane Kobayashi, MD, PhD (University of Texas Southwestern)	Dr. Kobayashi has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Knight pharmaceuticals. Dr. Kobayashi has received personal compensation in the range of $0-$499 for serving as a Consultant for Creative Research Designs. Dr. Kobayashi has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Jazz Pharmacuticals. Dr. Kobayashi has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Paladin Laboratories. Dr. Kobayashi has received personal compensation in the range of $0-$499 for serving as a author with Medlink .

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