Stellenwert frühzeitiger langzeit-EEG-ableitungen nach akuter zerebraler ischämie

Introduction: There is substantial lack of well-designed functional electrophysiological studies with respect to pathophysiology and prognosis after cerebral ischaemia despite increasing progress in neuroimaging. Methods: We prospectively investigated 25 consecutive patients with acute first-ever supratentorial ischaemic stroke and no history of epilepsy. 24h-EEG monitoring was started within 12 hours after the onset of symptoms. The neurological deficit was assessed by NIH Stroke Scale (NIHSS) and Barthel Index (BI) during EEG recording and after 1 year. Results: Blinded EEG evaluation revealed 3 hierarchical classes: focal slowing (n = 9, group C), focal high voltage discharges (n = 10, group B) and epileptiform activity (n = 6, group A). Temporo-spatial EEG evolution was illustrated in reproducible time series and thus allowed a refined analysis of the underlying pathophysiology. Slowing-down of the background activity, occurrence of contralateral potentials and rhythmic focal slowingdown seemed to correlate with a higher incidence of high-voltage discharges and epileptiform activity. The EEG groups differed significantly (p < 0.0001) in NIHSS BI and in the occurrence of seizures. All patients of group C had a good outcome (NIHSS < 10, BI > 60) and no one developed seizures (predictive value [pv] = 1: 95% confidence interval [CI] 0,72-1). In contrast all patients of group A had a poor outcome (NIHSS > 20, BI < 20 or death; PV 1, CI 0,61-1) and 5 of them developed seizures (PV 0,83: Cl 0,36-1). Patients with epileptic seizures had a significant higher mortality (p < 0.025) Conclusions: Our data underline the importance of early post-ischaemic EEG recording both for understanding pathophysiological mechanisms of post-ischaemic seizures and the prognosis of acute stroke.