Electroencephalography improves the prediction of functional outcome in the acute stage of cerebral ischemia.

BACKGROUND AND PURPOSE We studied the value of clinical and electroencephalographic assessment in patients with acute first-ever supratentorial ischemia in predicting functional outcome after 1 year. METHODS In 55 consecutive patients admitted after a median interval of less than 24 hours, the degree of handicap was dichotomized as moderate (Rankin grade 1, 2, or 3) or severe (Rankin grade 4 or 5). Clinical deficits were categorized according to signs of a lacunar or a cortical syndrome. Without knowledge of clinical data, electroencephalograms (EEGs) were classified according to findings predicting good or poor prognosis. The outcome after 1 year was assessed as good (Rankin grade 3 or less) or poor (Rankin grade 4 or 5 or death from stroke) and was correlated to clinical data and to EEG findings in the acute stage. RESULTS Thirty patients with a moderate handicap on admission all had a good outcome (predictive value [PV] of the initial handicap, 1.00; 95% confidence interval [CI], 0.88 to 1.00). Of the 25 patients with severe handicap on admission a poor outcome occurred in 13 (PV, 0.52; 95% CI, 0.31 to 0.72). If these patients with severe handicap at baseline were subdivided according to clinical features, a lacunar syndrome predicted good outcome in 4 of 5 patients (PV, 0.80; 95% CI, 0.28 to 1.00), but a cortical syndrome predicted poor outcome in only 12 of 20 patients (PV, 0.60; 95% CI, 0.36 to 0.81). Of the 20 patients with severe handicap and a cortical syndrome at baseline, an EEG with features predicting a good prognosis correctly predicted good outcome in 6 of 7 patients (PV, 0.86; 95% CI, 0.42 to 1.00). An EEG with features predicting poor prognosis correctly predicted poor outcome in 11 of 13 patients (PV, 0.85; 95% CI, 0.55 to 0.98). CONCLUSIONS Electroencephalography improves the prediction of functional outcome in patients with a severe neurological deficit in the acute stage of cerebral ischemia. This may have implications for the design of future intervention trials in acute stroke.