Park TH, Lee JK, Park MS, et al. - Researchers conducted this prospective observational study to improve epidemiologic knowledge of neurologic deterioration (ND) in patients with acute ischemic stroke (AIS). They found ND prospectively in 29,446 AIS patients admitted to 15 hospitals in Korea within 7 days of stroke onset. According to results, ND occurred in 4,299 (14.6%) patients. ND was associated with old age, female sex, diabetes, early arrival, large artery atherosclerosis as a stroke subtype, high NIHSS scores, glucose level, systolic blood pressure, leukocytosis at admission, recanalization therapy, TIA without a relevant lesion, and steno-occlusion of relevant arteries. As a factor that can affect the outcome of acute ischemic stroke, ND should be accounted for.