Abdul-Rahim AH, Fulton RL, Sucharew H, Kleindorfer D, Khatri P, Broderick JP, et al. National Institutes of Health Stroke Scale Item Profiles as Predictor of Patient Outcome: External Validation on Safe Implementation of Thrombolysis in Stroke–Monitoring Study Data. Stroke. 2015
Dr. Abdul-Rahim and colleagues set out to validate the NIHSS Item profiles (see table) as predictors of outcomes in patients receiving thrombolysis therapy for ischemic stroke in a prospectively collected database.
They applied the NIHSS item profiles to 6843 patients from the SITS-MOST cohort with A being the most severe profile to F being the mildest. There was no notable difference in the onset to treatment delay nor in the dosage of tPA across the profiles. Ordinal analysis of mRS at day 90, adjusted for age, sex and pre-stroke mRS, confirmed greater odds of better outcome across all profiles, B-F, when compared against Profile A. The dichotomized outcomes and the overall survival analysis at 90 days, mirrored the findings from the ordinal analysis. There were statistically significant differences for good outcome, mortality and survival rates when comparing Profile C with Profile D, with Profile D consistently associated with worse outcomes than Profile C. Profiles C and E, which shared a common median baseline NIHSS, did not differ in terms of mortality and survival rates, when compared to each other after adjustment.
To compare the performance of symptoms profiles generated from baseline NIHSS with the 24-hour NIHSS, they applied the probabilities of profile membership onto 24-hour NIHSS data, to generate six distinct 24hour-NIHSS item profiles (Profiles a to f). There were clear distinctions in the survival curves between Profiles a and b versus the remaining profiles. There were significant differences in discrimination ability for the dichotomized outcomes between the baseline- and 24hour-NIHSS items profiles.
Identifying NIHSS for their individual components may be crucially important rather than just an overall score as shown by the authors in this paper. This classification may also be helpful in triaging patients given its prognostic value.
I can really see no use of this scale for prediction, it is totally subjective. What would be useful is MRI and PET scans delineating 3 dimensional areas of dead and damaged neurons. You can't tell anything from this if the stroke was in the cerebrum, the cerebellum or the white matter. Location is important.