The prognostic value of the components of the Glasgow Coma Scale following acute stroke

BACKGROUND: The Glasgow Coma Scale (GCS) is widely used in assessing level of consciousness. The GCS verbal component may be misleading in acute stroke: a focal neurological deficit leading to dysphasia could affect the score, independently of level of consciousness. AIM: To investigate the relationship, in all strokes and in dysphasic patients, between stroke outcome and total GCS (with and without the verbal score) and its components, to assess their relative values. STUDY DESIGN: Retrospective analysis following prospective data collection in an acute stroke unit and follow-up. METHODS: Outcomes studied were 2-week mortality and 3-month recovery (survival, subject living at home). We used area under the receiver operating characteristic curve (AUC) to compare versions of the GCS and multivariate logistic regression to identify which subset of GCS components best predicted outcome. RESULTS: Of 1517 patients with acute stroke, 1217 had complete clinical and follow-up data; 349 were dysphasic. Total GCS had greater AUC than the GCS without the verbal score, for mortality (all patients 0.78 vs. 0.76, p=0.021; dysphasics 0.72 vs. 0.71, p=0.52) and recovery (all patients 0.71 vs. 0.67, p=0.0001; dysphasics 0.74 vs. 0.70, p=0.055). Verbal and eye scores independently provided prognostic information, for each patient group and outcome measure. CONCLUSIONS: The GCS contains valuable predictive information. Regardless of whether dysphasia is present, the verbal score should be assessed since it adds prognostic information to that from the eye component, and has greater value than the motor score.