What is the Role of Continuous Electroencephalography in Acute Ischemic Stroke and the Relevance of the "Ictal-Interictal Continuum"?

Associated Factors and Prognostic Implications of Non-convulsive Status Epilepticus in Ischemic Stroke Patients With Impaired Consciousness

Background and Purpose: Non-convulsive status epilepticus (NCSE) is common in patients with disorders of consciousness and can cause secondary brain injury. Our study aimed to explore the determinants and prognostic significance of NCSE in stroke patients with impaired consciousness.

Method: Consecutive ischemic stroke patients with impaired consciousness who were admitted to a neuro intensive care unit were enrolled for this study. Univariate and multivariable logistic regression were used to identify factors associated with NCSE and their correlation with prognosis.

Results: Among the 80 patients studied, 20 (25%) died during hospitalization, and 51 (63.75%) had unfavorable outcomes at the 3-month follow-up. A total of 31 patients (38.75%) developed NCSE during 24-h electroencephalogram (EEG) monitoring. Logistic regression revealed that NCSE was significantly associated with an increased risk of death during hospital stay and adverse outcomes at the 3-month follow-up. Patients with stroke involving the cerebral cortex or those who had a severely depressed level of consciousness were more prone to epileptogenesis after stroke.

Conclusion: Our results suggest that NCSE is a common complication of ischemic stroke, and is associated with both in-hospital mortality and dependency at the 3-month follow-up. Long-term video EEG monitoring of stroke patients is, therefore required, especially for those with severe consciousness disorders (stupor or coma) or cortical injury.

Stroke-Onset Seizures During Midbrain Infarction in a Patient With Top of the Basilar Syndrome

Risk factors for early-onset seizures in acute ischemic stroke include anterior circulation stroke, infarction of the cerebral cortex, large infarct size, and ischemic-to-hemorrhagic transformation. We define stroke-onset seizures as seizures occurring within 2 hours of stroke onset. A 64-year-old woman presented with top of the basilar artery syndrome-thalamic infarction occurred first and midbrain infarction 12 days later. She manifested stroke-onset seizures during midbrain infarction, which was heralded by stupor. Within 2 hours of the onset of stupor, she had a clonic seizure of the lower extremities, electroencephalography (EEG) revealed nonconvulsive status epilepticus, and an episode of convulsive movements of all extremities was recorded on video and on EEG. Continuous EEG recording showed epileptiform discharges that would appear, disappear, and reappear over a 3-week period. It took 3 weeks and 4 antiepileptic drugs to fully suppress cortical hyperexcitability, perhaps because injury to some midbrain structures resulted in global lowering of the seizure threshold. The most important risk factor for stroke-onset seizures appears to be posterior circulation stroke, particularly brainstem infarction. The difference in risk profile between stroke-onset seizures and other forms of early-onset seizures suggest that their pathophysiology is not exactly the same. Focusing some of the research spotlight on stroke-onset seizures can help us better understand their unique clinical, electrographic, radiologic, and pathophysiologic features.