title: Shortening the NIH Stroke scale for use in the prehospital setting.
abstract: OBJECTIVE
  Prehospital stroke scales should identify stroke patients and measure stroke severity. The goal of this study was to identify a subset of the 15 items in the National Institutes of Health Stroke Scale (NIHSS-15) that measures stroke severity and predicts outcomes.
  
  
  METHODS
  Using 2 distinct data sets from acute stroke clinical trials, we derived and validated shortened versions of the NIHSS (sNIHSS). Stepwise logistic regression and bootstrap techniques were used in selection of NIHSS-15 items. Areas under the receiver operator characteristic curve (C statistics) were used to compare predictive performance of logistic models incorporating differing versions of the NIHSS.
  
  
  RESULTS
  The derivation analyses suggested the 8 NIHSS-15 items that were most predictive of "good outcome" 3 months after stroke, in order of decreasing importance: right leg item, left leg, gaze, visual fields, language, level of consciousness, facial palsy, and dysarthria. The sNIHSS-8 comprises all 8 and the sNIHSS-5, the first 5. In the validation models, C statistics were NIHSS-15=0.80, sNIHSS-8=0.77, and sNIHSS-5=0.76. Statistical comparisons suggested that the NIHSS-15 had better predictive performance than the sNIHSS-8 or the sNIHSS-5; the absolute difference in C statistics was small. There was no significant difference between the sNIHSS-8 and the sNIHSS-5.
  
  
  CONCLUSIONS
  Much of the predictive performance of the full NIHSS-15 was retained with a shortened scale, the sNIHSS-5. Shortening the NIHSS-15 will facilitate its use during prehospital evaluations. The sNIHSS severity information may be useful to triage acute stroke patients in communities and to provide a baseline stroke severity for prehospital acute stroke trials.
authors.affiliation: Department of Neurology, Harborview Medical Center, University of Washington School of Medicine, Seattle, USA.tirsch@u.washington.edu
authors.forename: David L
authors.initials: DL
authors.lastname: Tirschwell
authors.forename: W T
authors.initials: WT
authors.lastname: Longstreth
authors.forename: Kyra J
authors.initials: KJ
authors.lastname: Becker
authors.forename: Richard E
authors.initials: RE
authors.lastname: Gammans
authors.forename: LuAnn A
authors.initials: LA
authors.lastname: Sabounjian
authors.forename: Scott
authors.initials: S
authors.lastname: Hamilton
authors.forename: Lewis B
authors.initials: LB
authors.lastname: Morgenstern
mesh_terms: D000208:Acute Disease; D000368:Aged; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D015331:Cohort Studies; D003943:Diagnostic Techniques, Neurological / Q000592:standards*; D004632:Emergency Medical Services / Q000592:standards*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D020521:Stroke / Q000175:diagnosis* / Q000503:physiopathology; D014218:Triage / Q000592:standards