Abstract Details

Title Increased Functional Connectivity During Epileptiform Discharges in Adult-Onset Mesial Temporal Lobe Epilepsy

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) P3 - Poster Session 3 (11:45 AM-12:45 PM)

Poster/Presentation
Number 9-005

Objective

To evaluate differences in brain functional connectivity during epileptiform discharges between adult-onset and pediatric-onset MTLE.

Background

Classical MTLE typically begins in childhood, characterized by unilateral hippocampal sclerosis with sparing of the CA2 region. Adult-onset MTLE is often marked by more diffuse hippocampal sclerosis affecting CA2 and contralateral involvement. Hyperphosphorylated tau deposition has been observed in adult MTLE, which also correlates with cognitive decline, suggesting a potential association with dementia.

Design/Methods Epileptiform discharges were manually identified from EEG recordings of nine adult-onset and six peds-onset MTLE patients. Each epileptiform discharge was segmented into five one-second epochs: baseline (-2 to -1 second), pre-spike (-1 to 0 second), spike (0 to +1 second), post-spike1 (+1 to +2 second), and post-spike2 (+2 to +3 second). Functional connectivity was analyzed using cross-correlation for each epoch and electrode pair. Inter-group and inter-epoch differences were evaluated with the Wilcoxon rank sum test and the False Discovery Rate method to account for multiple comparisons.

Results

The peds-onset MTLE had a longer disease duration (P=0.03). Rates of bilateral independent temporal onset epilepsy (33.3% adult vs 50% peds), hippocampal sclerosis (55.5% adult vs 66.7% peds), and anterior temporal hypometabolism on PET (88.9% adult vs 83.3% peds) were similar. The age (P=0.93) and mean number of epileptiform discharges were comparable (P=0.93).

Connectivity and node strengths increased from baseline to the spike epoch in both groups, then decreased post-spike, with post-spike2 levels lower than baseline. The adult-onset MTLE group showed increased degree and strength of connectivity in bilateral temporal and occipital lobes, and ipsilateral parietal lobe during the pre-spike (P<0.03). No significant inter-group differences were found in other epochs.

Conclusions

Adult-onset MTLE may be functionally distinct from peds-onset MTLE. The more extensive synchronization of brain networks suggests that epileptiform discharges could have a wider impact in adult-onset MTLE, potentially contributing to the development of dementia-related phenotype.

Authors/Disclosures
Brian Jung, MD PRESENTER	Dr. Jung has nothing to disclose.
Sebastian Hanna, MD	Mr. Hanna has nothing to disclose.
Lilit Mnatsakanyan, MD (UC Irvine Medical Center)	Dr. Mnatsakanyan has nothing to disclose.
Mona Sazgar, MD (University of California, Irvine)	Dr. Sazgar has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Eisai. Dr. Sazgar has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Xenon. Dr. Sazgar has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for UCB. Dr. Sazgar has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Neurelis. Dr. Sazgar has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Eisai. Dr. Sazgar has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for SK Lifesciences. The institution of Dr. Sazgar has received research support from UCB. Dr. Sazgar has received publishing royalties from a publication relating to health care.
Sumeet Vadera, MD	Dr. Vadera has nothing to disclose.
Richard J. Staba, PhD	Prof. Staba has nothing to disclose.
Jerome Engel, Jr., MD, PhD, FAAN (Reed Neurological Research Ctr)	Dr. Engel has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Cerebel. Dr. Engel has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Eisai. Dr. Engel has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for MedLink. Dr. Engel has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Steven Barris. Dr. Engel has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Cutler Law Firm. Dr. Engel has received publishing royalties from a publication relating to health care. Dr. Engel has received publishing royalties from a publication relating to health care. Dr. Engel has received publishing royalties from a publication relating to health care. Dr. Engel has received publishing royalties from a publication relating to health care.

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