Abstract Details

Title Quantitative Pupil Measurements In Epileptic Seizures And Non-Epileptic Events – A Step Towards SUDEP Pathophysiologic Mechanisms.

Topic Epilepsy/Clinical Neurophysiology (EEG)

Presentation(s) P1 - Poster Session 1 (5:30 PM-6:30 PM)

Poster/Presentation
Number 6-017

Objective This pilot study evaluated pupillary reactions immediately after epileptic and non-epileptic events to understand the autonomic changes during postictal periods.

Background The autonomic nervous system activates during seizures. Objective measures of pupillary reactions indirectly measure the sympathetic and parasympathetic responses.

Design/Methods

This is a IRB approved single center study. A handheld device (Neuroptics) approved by Food and Drug Administration measured pupil changes before and after seizure using an infrared light stimulus. Three patients admitted to long term monitoring unit were enrolled for total of four electrographically confirmed epileptic and one non-epileptic events. Five baseline pupil measurements were taken for each patient. Time stamped, Post ictal recordings captured immediately after seizure and up to one hour after seizure and analyzed offline. Maximum baseline pupil diameter(BPA Max), Minimum baseline pupil diameter(BPA Min), Latency (Tlat), Constriction percentage (C% : BPA Max-BPA Min/BPA Max X 100), Constriction Velocity (CV: BPA Max-BPA Min/Tmin) were collected.

Results

Postictally there was 25 percent decrease in the pupil diameter and constriction velocity from baseline within first 10 minutes in focal right temporal lobe seizure and first 20 minutes in frontal with secondary generalization seizure. This is significant compared to normative data from pupillometer validation studies (8% pupil diameter variation). No difference from baseline pupil reaction measurements noted with non-epileptic events.

Conclusions

Pharmacological studies showed that parasympathetic blockade increased BPA Max, and decrease in C% and CV. While, sympathetic blockade decreases BPA Max with no influence on other parameters. The results suggest that the decrease in BPA Max is due to either sympathetic blockade or increase in parasympathetic activity immediately postictal. The decrease in constriction velocity suggests parasympathetic blockade. Together, there might be both sympathetic and parasympathetic blockade with more sympathetic blockade. These results partly support the current pathophysiologic hypothesis of sudden unexpected death in epilepsy (SUDEP) which includes autonomic instability with parasympathetic suppression.

Authors/Disclosures
Sushma R. Yerram, MD (Texas tech University of Health Sciences) PRESENTER	Dr. Yerram has nothing to disclose.
Lynn Liu, MD, FAAN (University of North Carolina - Chapel Hill)	Dr. Liu has nothing to disclose.
David V. Lardizabal, MD, FAAN (Charleston Area Medical Center)	Dr. Lardizabal has nothing to disclose.
Shawn M. Whitton, MD	No disclosure on file
Sharmila Suri Mohanram, MD (Capital Region Medical Center)	No disclosure on file

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