Timing of Neurological Improvement after Acute Ischemic Stroke and Functional Outcome

<b><i>Background:</i></b> The time of neurological improvement (TNI) after acute ischemic stroke may have a predictive value. <b><i>Methods:</i></b> We evaluated 410 consecutive patients who were admitted within 12 hours of stroke onset. The National Institutes of Health Stroke Scale (NIHSS) was measured on admission and at 1, 3, 7, and 14 days. Neurological improvement was defined as an improvement in the NIHSS score by ≥2 points (NI2) or ≥4 points (NI4) or an NIHSS score of 0. Patients with a Modified Rankin scale (mRS) score of ≤2 were considered to have a good outcome. <b><i>Results:</i></b> Patients with earlier TNIs had a lower 3-month mRS score and a higher probability for a good outcome. In the binary and ordinal regression analyses, age, NIHSS score, atrial fibrillation and TNI were independently associated with a good outcome. Receiver operating characteristic curve analyses demonstrated that TNI2 had higher sensitivity and lower specificity than TNI4. The best threshold for predicting outcome was day 3 for TNI2 and day 14 for TNI4. <b><i>Conclusions:</i></b> These results suggest that TNI is independently associated with functional outcome at 90 days. TNI2 may be more useful than TNI4 for early prediction of stroke outcome.