National Institutes of Health Stroke Scale Certification Is Reliable Across Multiple Venues

Abstract

Background and Purpose— National Institutes of Health Stroke Scale certification is required for participation in modern stroke clinical trials and as part of good clinical care in stroke centers. A new training and demonstration DVD was produced to replace existing training and certification videotapes. Previously, this DVD, with 18 patients representing all possible scores on 15 scale items, was shown to be reliable among expert users. The DVD is now the standard for National Institutes of Health Stroke Scale training, but the videos have not been validated among general (ie, nonexpert) users. Methods— We sought to measure interrater reliability of the certification DVD among general users using methodology previously published for the DVD. All raters who used the DVD certification through the American Heart Association web site were included in this study. Each rater evaluated one of 3 certification groups. Results— Responses were received from 8214 raters overall, 7419 raters using the Internet and 795 raters using other venues. Among raters from other venues, 33% of all responses came from registered nurses, 23% from emergency department MD/other emergency department/other physicians, and 44% from neurologists. Half (51%) of raters were previously National Institutes of Health Stroke Scale-certified and 93% were from the United States/Canada. Item responses were tabulated, scoring performed as previously published, and agreement measured with unweighted kappa coefficients for individual items and an intraclass correlation coefficient for the overall score. In addition, agreement in this study was compared with the agreement obtained in the original DVD validation study to determine if there were differences between novice and experienced users. Kappas ranged from 0.15 (ataxia) to 0.81 (Item 1c, Level of Consciousness-commands [LOCC] questions). Of 15 items, 2 showed poor, 11 moderate, and 2 excellent agreement based on kappa scores. Agreement was slightly lower to that obtained from expert users for LOCC, best gaze, visual fields, facial weakness, motor left arm, motor right arm, and sensory loss. The intraclass correlation coefficient for total score was 0.85 (95% CI, 0.72 to 0.90). Reliability scores were similar among specialists and there were no major differences between nurses and physicians, although scores tended to be lower for neurologists and trended higher among raters not previously certified. Scores were similar across various certification settings. Conclusions— The data suggest that certification using the National Institute of Neurological Disorders and Stroke DVDs is robust and surprisingly reliable for National Institutes of Health Stroke Scale certification across multiple venues.