Abbreviation of the Follow-Up NIH Stroke Scale Using Factor Analysis.

Area of Science:

• Neurology
• Clinical Neuroscience
• Stroke Research

Background:

• The NIH Stroke Scale (NIHSS) is a 15-item assessment of stroke-related neurologic deficits.
• A 24-hour NIHSS measurement is highly predictive of long-term functional outcomes.
• A simplified scale may offer improved prognostic accuracy and interrater reliability.

Purpose of the Study:

• To develop and validate a simplified 24-hour NIH Stroke Scale (aNIHSS).
• To identify the most predictive components of the NIHSS for stroke outcomes.
• To compare the prognostic accuracy and reliability of the aNIHSS with the full NIHSS.

Main Methods:

• Post hoc analysis of the Interventional Management of Stroke-3 (IMS-3) trial data.
• Principal component analysis (PCA) was used to identify key variables in the 24-hour NIHSS.
• Prognostic accuracy (AUC) for good and poor outcomes was compared between abbreviated and full NIHSS iterations.
• Validation was performed using the NINDS-TPA study cohort.
• Interrater reliability was assessed using published datasets.

Main Results:

• A 3-variable abbreviated NIHSS (aNIHSS) comprising aphasia, neglect, and arm weakness demonstrated excellent prognostic accuracy (AUC=0.90) for good outcomes.
• The aNIHSS was more predictive than the baseline NIHSS (AUC=0.73) and comparable to the full 24-hour NIHSS (AUC=0.91).
• Validation in the NINDS-TPA cohort confirmed the aNIHSS prognostic accuracy (AUC=0.89 vs. 0.92 for full NIHSS).
• An aNIHSS score >9 predicted very poor outcomes.
• The aNIHSS exhibited higher interrater reliability (mean kappa 0.80) compared to the full NIHSS (0.73).

Conclusions:

• Aphasia, neglect, and arm weakness at 24 hours post-ischemic stroke are key predictors of outcome.
• The abbreviated NIHSS (aNIHSS) offers strong prognostic accuracy and enhanced reliability.
• The aNIHSS may serve as a valuable clinical tool for stroke outcome prediction.