Reduction of Stimulation Evoked Interictal Discharges During Sleep
Abstract number :
2.044
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2022
Submission ID :
2205111
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:28 AM
Authors :
Rina Zelmann, PhD – Massachusetts General Hospital; Angelique Paulk, PhD – Instructor, Neurology, Massachusetts General Hospital; Jaquelin Dezha-Peralta, BEng – Neurology – Massachusetts General Hospital; Ziv Williams, MD,PhD – Neurosurgery – Massachusetts General Hospital; Mark Richardson, MD,PhD – Neurosurgery – Massachusetts General Hospital; Wilson Truccolo, PhD – Neuroscience – Brown University; Sydney Cash, MD,PhD – Associate Professor, Neurology, Massachusetts General Hospital
Rationale: It is well known that spontaneous interictal epileptiform discharges (IIDs) increase during sleep. On the other hand, the brain’s response to electrical stimulation during sleep is less complex with reduced effective connectivity. This study investigates the relation between sleep and stimulation evoked epileptic discharges.
Methods: Eleven patients with depth electrodes implanted to localize their epileptic focus underwent pseudo-random multi-region electrical stimulation while they were awake and asleep. Stimulation sites included the clinical seizure onset zone (SOZ). Single pulse electrical stimulation (SPES) was delivered to two adjacent contacts at seven mA, biphasic pulse duration 0.253 ms, every 3 to 5 s +/-0.25s (random jitter). Ten to 20 pulses were delivered to each location at each state. The response of each bipolar intracranial EEG channel was visually assessed to determine the presence of evoked IIDs during wake and during sleep.
Results: In ten of the patients, it was possible to evoke IIDs with SPES delivered to the SOZ. In six of these cases, the IIDs disappeared in most channels when the same SPES was delivered to the same channels during sleep. Even in the four cases where there was a response in the same channels, the amplitude was smaller and the extent more local. Figures 1 and 2 show representative examples of the brain’s response to stimulation during wake and sleep.
Conclusions: Contrary to intuition, stimulation evoked IIDs were reduced during sleep compared to wake. This is a step towards understanding the interplay between sleep and epilepsy, with important implications for neuromodulatory therapy.
Funding: This work was supported by a CURE Epilepsy foundation Taking Flight Award, the Tiny Blue Dot Foundation, NIH grant K24-NS088568, and NIH grant R01-NS062092. RZ was supported by a CURE Epilepsy Foundation Taking Flight Award.
Neurophysiology