Abstracts

RATIONALE: Well-designed functional studies with respect to early pathophysiological developement, hyperexcitability, icto- and epileptogenesis after stroke are rare. METHODS: We prospectively investigated 25 consecutive patients with first-ever supratentorial ischemic stroke and no history of epilepsy. 24h-EEG-monitoring was started within 12 hours after the onset of symptoms. 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). Slowing of the background activity, occurrence of contralateral potentials and rhythmic focal slowing seemed to influence the developement of high voltage discharges and epileptiform activity. The groups differed in the occurrence of seizures (p < 0,001). 5 of 6 patients with epileptiform discharges (predictive value [PV] 0,83; 95% confidence interval [CI] 0,36 to 1) but no patient with only focal slowing (PV 1; 95% CI 0,72 to 1) developed seizures within 1 year. 4 patients had early seizures, who all belonged to group A. Of the patients with late seizures 3 out of 4 had high voltage discharges. In 3 of them the seizures recurred (epilepsy). Developement of epileptiform activity and seizures was associated with clinical deterioration and a worse outcome (Barthel Index < 20, death) (p < 0,00005). CONCLUSIONS: Our data emphasize the importance of post-ischemic early systematic EEG recordings for understanding of both icto- and epileptogenesis.