Abstract Details

Title Seizures are locked to long time-scale rhythms in epilepsy

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) P5 - (-)

Poster/Presentation
Number 411

Background Epilepsy is defined by the seemingly random occurrence of seizures. However, recent quantitative analyses have described circadian and cluster organization, suggesting that seizures may be temporally regulated over long timescales. An extension of this concept is whether seizure timing is related to fluctuations in Interictal Epileptiform Activity (IEA), a marker of brain irritability. We quantified continuous IEA and seizure detection from 37 patients implanted intracranially for years with the Responsive NeuroStimulation system1 (ambulatory electrocorticography).

Objective

Design/Methods We formatted IEA hourly counts into continuous time-series and applied wavelet decomposition to determine any component multidien rhythms. In a subset of 14 patients who had reliable seizure detection, we then estimated the phase timing of seizures in relation to peak periodicities of IEA using circular statistical analyses (mean resultant vector length, Omnibus test).

Results Beyond the expected circadian distribution of IEA (confirmed here), we also found robust superimposed multidien rhythms of IEA. Cycle durations differed between patients, and they were stable over time including some recorded up to 10 years. Both females and males demonstrated these multidien rhythms, and there was no coherence with the lunar cycle. Seizures were phase-locked to the underlying multidien rhythms of IEA, occurring preferentially during the upslope of the period (p<0.05 for 13 out of 14 subjects).

Conclusions Using very long continuous electrocorticography recordings, we found that seizures and IEA are substantially influenced by underlying rhythms in long timescales (several days to weeks or more). These multidien rhythms suggest underlying therapeutic endocrine or metabolic targets that deserve further study. They also highlight opportunities to decrease refractory seizure burden through dynamic predictive therapeutic adjustments.

Authors/Disclosures
Maxime Baud, MD, PhD (University of California, SF (UCSF))	No disclosure on file
Jonathan Kleen, MD, PhD (University of California, San Francisco)	Dr. Kleen has nothing to disclose.
Emily Mirro	No disclosure on file
	No disclosure on file
David King-Stephens, MD (University of California, Irvine)	Dr. King-Stephens has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Neurelis. Dr. King-Stephens has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for UCB. Dr. King-Stephens has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Neurelis.
Edward F. Chang, MD	No disclosure on file
Vikram Rao, MD (UC San Francisco)	Dr. Rao has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for LivaNova. Dr. Rao 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 Elsevier. Dr. Rao has stock in Novela Neurotechnologies. Dr. Rao has stock in EnlitenAI. The institution of Dr. Rao has received research support from NeuroPace, Inc.. The institution of Dr. Rao has received research support from Medtronic.