Distribution of National Institutes of Health Stroke Scale in the Cincinnati/Northern Kentucky Stroke Study

Abstract

Background and Purpose— Little is known about the distribution of National Institutes of Health Stroke Scale (NIHSS) scores from patients with ischemic stroke sampled from population-based studies. We describe the distribution of NIHSS in ischemic stroke cases from the Cincinnati/Northern Kentucky Stroke Study. Methods— Within a biracial population of 1.3 million, all strokes among area residents in 2005 were ascertained by screening discharge records at local hospitals and outpatient clinics. A sampling scheme was developed to ascertain additional cases presenting to physician offices and nursing homes, not identified through the other sources. All confirmed ischemic stroke cases underwent chart abstraction, and a retrospective NIHSS (rNIHSS) score (range, 0–42) was generated on the basis of initial physician examination findings. Results— There were 2233 ischemic stroke cases identified during the 12-month study. The overall median rNIHSS score was 3 (interquartile range, 1–7). Median rNIHSS score was 3, 7, and 1, respectively, for stroke cases ascertained through the admitted, in-hospital, and out-of-hospital sources. Median rNIHSS was significantly higher in subjects ≥80 years compared with younger cases (4 versus 3). Conclusions— More than half of all ischemic stroke cases have mild symptom severity on initial presentation (ie, rNIHSS≤3). Monitoring trends in NIHSS represents a legitimate target for population-based surveillance efforts.