The Effect of Training and Certification for the NIHSS and the mRS on Rater Performance: A Systematic Review

Up-to-date certification of the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) is often required for clinical trials, representing a significant burden on clinical investigators globally.

This systematic review sought to determine if NIHSS or mRS training, re-training, certification or recertification led to improvements in the reliability or accuracy of ratings as well as other relevant user metrics (e.g., user confidence).

Among 4227 studies, 100 passed screening and were assessed for eligibility with full-text review; 23 met inclusion criteria. Among these 23 studies, 22 examined NIHSS training and/or certification, and only a single study included examined the effect of training on mRS performance. Ten of 23 included studies were conference abstracts. The study designs, interventions and outcome measurement of the included studies were heterogeneous. In the case of the NIHSS, two studies found increased accuracy after NIHSS training, and a third study showed statistically significant though clinically trivial decreases in error rate with training. The remaining 19 studies showed no benefit of NIHSS training as it relates to reliability or accuracy outcomes. The single included mRS study did not show the benefit of training.

Although data are sparse with heterogeneous training protocols and outcomes, there is no compelling evidence to suggest benefit of healthcare professionals completing NIHSS or mRS training, certification or recertification. At the very least, recertification/re-training requirements should be reconsidered pending the provision of robust evidence.