Abstracts

Rationale: Stroke is one of the most common causes of seizure especially in the elderly (Epileptic Disord. 1;22(3):252-263). The incidence of post stroke seizures varies in the literature from 9-11%. Early post stroke seizures are more common in the first two weeks after stroke, especially in the first 24 hours after stroke. Late post stroke seizures, usually after two weeks, are less common but have a higher recurrence rate (Postgraduate Medical Journal. 82 (971): 568). EEG is a non-invasive, simple, portable tool for diagnosis and prognosis of recurrent seizures and early EEG abnormalities can predict post stroke seizure. We sought to identify EEG patterns that could differentiate early and late post stroke seizure patients.

Methods: This is an IRB approved retrospective study including patients who presented to Temple Hospital from 1/1/2014 to 12/31/2019. Clinical data of 200 patients were reviewed using an Electronic Medical Record (EMR). Those who had confirmed stroke and a first episode of seizure after stroke were included. Among 200 patients, 80 patients met the inclusion criteria. The EMRs were reviewed and demographic data, brain imaging findings, seizure type and EEG findings were recorded. The location of stroke, seizure type and EEG characteristics were compared between patients with early versus late post stroke seizure using t test and Chi-squared statistics.

Results: The age range was 46-89 years with a mean age of 67 years; 53% were female and 47% were male. Only 5% had hemorrhagic stroke; the remaining 95% had ischemic strokes. The most common stroke location was in the frontal lobe, followed by parietal, occipital, and temporal lobes. Focal seizure with impaired awareness occurred in 83% of the patients, while only 1% had generalized seizures. Half of the patients (40/80) had seizure in the first two weeks of stroke and 90% of them had seizure in the first 24 hours after stroke. Among 50% (40/80) with late post stroke seizure, the majority of patients had seizure after one year post stroke. In terms of EEG findings, 65% had focal slowing, 58% had generalized slowing, 23% had sharp waves and only 6% had lateralized periodic discharges (LPD).

Location of stroke was more common in the frontal lobes in both groups. Twenty-five patients with early post stroke seizure had parietal lobe involvement, while 12 patients with late post stroke seizure had parietal involvement. However, there was no statistically significant difference between these two groups.

Conclusions: EEG patterns in the majority of patients with post stroke seizure were focal slowing, followed by generalized slowing. However, our study showed only a small number of patients with LPD on EEG. There was no statistically significant difference in location of stroke, seizure type and EEG characteristics between patients with early versus late post seizures. Further study with a larger sample size is warranted to clarify whether a trend toward early post stroke seizures with parietal lobe stroke location is clinically significant.

Funding: Please list any funding that was received in support of this abstract.: None.