EEG patterns and epileptic seizures in acute phase stroke

• Published in: Neurophysiologie clinique Vol. 48; no. 3; p. 129
• Main Authors: Bouattour, Nadia, Farhat, Nouha, Bouchaala, Wafa, Kacem, Hanen Haj, Hdiji, Olfa, Sakka, Salma, Dammak, Mariem, Mhiri, Chokri
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01-06-2018; Elsevier Science Ltd
• Subjects: Acute stroke; Cerebral infarction; Convulsions & seizures; Early seizures; EEG; Electroencephalography; Epilepsy; Etiology; Geriatrics; Hemorrhage; Ischemia; Periodic lateralized epileptiform discharges; Seizures; Stroke; Early seizures; Periodic lateralized epileptiform discharges; Acute stroke
• ISSN: 0987-7053; 1769-7131
• DOI: 10.1016/j.neucli.2018.05.005

Acute symptomatic seizures and epilepsy in the elderly are caused in most of the cases by stroke [2]. Seizures after stroke are usually divided into early and late seizures according to the International League Against Epilepsy (ILAE). Prevalence of early post-stroke seizures reported in the literature varies from 2 to 33%, with most seizures occurring within the first 24h [1,3]. The aim of this study was to analyze patterns on EEGs performed within 24h of seizures onset and to investigate correlations between these patterns and the occurrence of early epileptic seizures.
A retrospective follow-up of 550 consecutive stroke patients: 380 ischemic brain infarction (IBI), 170 intracerebral hemorrhage (ICH), was conducted for a mean period of 5 years after stroke. Patients with a history of epilepsy were excluded from follow-up. Patients were investigated etiology of stroke. Epilepsy was defined according to the (ILAE) criteria.
Mean age was 67.24 (±12.17 years). Early seizures was observed in 51 (9.2%) patients: (41/380) with IBI and (11/170) with ICH. Early status epilepticus (SE) observed in (2/51). Forty patients developed late seizures and 76 developed vascular epilepsy. The average time to occurrence was 72hours for early seizures and 10 months for late seizures. Early Seizures were generalized in more half of the cases (56.8%). EEG was performed in the acute stage in 20 (20/51) patients. It showed periodic lateralized epileptic discharges (PLEDs) (8/20), diffuse slowing (5/20), focal slowing (10/20), spikes and slow sharp-waves (5/20) and was normal in 4 cases. We had not detected non-convulsive SE. PLEDs have been correlated with forthcoming seizures and vascular epilepsy, all patients with PLEDs developed epilepsy. We found that the risk of vascular epilepsy is significantly related to the abnormalities of EEG (P<0.001).
EEG in the acute phase of stroke may help to detect specific patterns, such as PLEDs, that are closely related to early seizures. EEG monitoring should be performed to identify purely electrographic seizures.