EEG Patterns and Epileptic Seizures in Acute Phase Stroke

Abstract

Background: The rate of early post-stroke epileptic seizures ranges from 2 to 33%. This wide range is likely due to differences in study design, patient selection and type of neurophysiological monitoring. Electroencephalography (EEG), which is not used in the routine work-up of acute stroke, is the best neurodiagnostic technique for detecting epileptic activity, especially in patients with non-convulsive post-stroke epileptic activity. The aim of this study was to analyze patterns on EEGs performed within 24 h of stroke onset, and to investigate correlations between these patterns and the occurrence of early epileptic seizures and status epilepticus (SE), vascular risk factors, stroke subtypes and short-term outcome. Methods: We prospectively studied 232 patients (mean age 71 ± 12 years; 177 ischemic strokes and 55 hemorrhagic). EEG recording was performed within 24 h from hospitalization. The follow-up lasted 1 week. Results: Fifteen patients (6.5%) had early seizures within 24 h; 10 of these patients had focal SE with or without secondary generalization. EEG revealed sporadic epileptiform focal abnormalities in 10% and periodic lateralized epileptiform discharges (PLEDs) in 6%. SE was recorded in 71.4% of patients with PLEDs. At the multivariate analysis, only early epileptic manifestations (p < 0.001) were independently associated with PLEDs. Conclusions: Our study confirms that seizures are not frequent in the early phase of acute stroke and occur prevalently as focal SE at onset. EEG may help to detect specific patterns, such as PLEDs, that are closely related to early seizures. EEG monitoring should be performed in order to detect purely electrographic seizures.

Electroencephalography Patterns and Prognosis in Acute Ischemic Stroke

“…Compared with similar studies, the frequency of EA and clinical seizures was higher [12]. The higher admission NIHSS (median 11) coupled with the inclusion of other PP as EA and the performance of EEG in later time points (up to 72 h) might explain our results.…”

“…Several studies have shown a strong association of PP (including lateralized periodic discharges and rhythmic delta activity) with the occurrence of seizures [3,9,10,12]. It is possible that some of these patterns, especially lateralized periodic discharges, represent an interictal-ictal continuum and might warrant early treatment [5,13].…”

The Utility of EEG, SSEP, and Other Neurophysiologic Tools to Guide Neurocritical Care

“…In the first 24 h after ischemic stroke, seizure occurs in ≤6.5% of patients [42], although two thirds of patients with seizures may develop status epilepticus, and rates may be >10% among patients with severe strokes [43]. Status may occur in >70% of patients with periodic discharges on EEG [42].…”

“…In the first 24 h after ischemic stroke, seizure occurs in ≤6.5% of patients [42], although two thirds of patients with seizures may develop status epilepticus, and rates may be >10% among patients with severe strokes [43]. Status may occur in >70% of patients with periodic discharges on EEG [42]. In addition to seizure detection, EEG has additional benefits in characterizing poor prognosis when there is background suppression, attenuation of fast frequencies [44], or when amplitude integrated values are low on quantitative EEG [45].…”

Seizures in Ischemic Stroke

“…PLEDs may be an expression of dynamic brain damage in the very acute stage. While PLEDs are commonly associated with large cortical destructive processes, they may be seen in patients with subcortical, chronic lesions, or metabolic disturbances [32,39]. Mecarelli et al analyzed the EEGs performed within 24 h of a cohort of 232 patients admitted with acute ischemic or intraparenchymal hemorrhagic stroke.…”