Abstract Details

Title The Effect of Sleep on the Ability to Induce Seizures or After Discharges Using Single Pulse Electrical Stimulation During Intracranial EEG Monitoring

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) P8 - Poster Session 8 (11:45 AM-12:45 PM)

Poster/Presentation
Number 10-001

Objective

To determine if sleep or drowsiness alters the seizure threshold for low frequency electrical stimulation in patients undergoing intracranial EEG (iEEG) monitoring.

Background Brain stimulation using single pulse electrical stimulation (SPES) is commonly performed on patients undergoing intracranial EEG monitoring for localizing drug-resistant seizures. SPES can map out effective connectivity between brain regions and can also induce seizures; seizures induced this way have a high specificity for predicting surgical outcomes. Currently, it is unknown whether the state of patient consciousness alters the ability to induce seizures by SPES.

Design/Methods We prospectively enrolled patients undergoing iEEG monitoring to receive SPES of all implanted contact pairs (5mA, 300uS, 1 Hz, 30 sec). Patients underwent stimulation on either day 1 or the final day of admission, depending on clinical availability. Patient state was recorded using both video and iEEG data.

Results There were a total of 2754 stimulations across 36 patients undergoing iEEG (2245 awake, 509 asleep/drowsy). Stimulations during wakefulness were more likely to induce epileptic activity than during drowsiness/sleep (136 awake vs 27 drowsy/asleep, P = 0.02). Stimulations that induced epileptic activity surprisingly had a higher ASM dose than those that did not (med 88% vs 85%, P = 0.044). Patients who had SPES at the beginning of admission were more likely to have seizures or after discharges than at the end of admission (112 vs 51, P = 0.006). A multivariate analysis of all of these variables demonstrated that patient state and ASM dose percentage significantly affected the ability to stimulate epileptic activity.

Conclusions

Our data suggests that patients are more likely to have seizures or after discharges induced with single pulse electrical stimulation when awake compared to asleep, although dose of ASM may have an effect.

Authors/Disclosures
Amy Grice, DO PRESENTER	Dr. Grice has nothing to disclose.
Helen Brinyark	Helen Brinyark has nothing to disclose.
Caila A. Coyne, MS	Ms. Coyne has nothing to disclose.
Rachel Smith (University of Alabama at Birmingham)	Rachel Smith has nothing to disclose.
Benjamin C. Cox, MD (University of Alabama at Birmingham)	The institution of Dr. Cox has received research support from American Epilepsy Society. The institution of Dr. Cox has received research support from Brain and Behavior Research Foundation.

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