Validation of Witness-Derived Secondary Cincinnati Prehospital Stroke Scale Scores for Prehospital Stroke Triage

INTRODUCTION: Prehospital delay in acute ischemic stroke is driven by decision delay between symptom recognition and taking action. Although witnesses recognize symptoms early, the value of translating witness-reported symptoms into standardized stroke assessment tools remains unclear. This study aimed to evaluate the predictive value of witness-derived, physician-administered secondary Cincinnati Prehospital Stroke Scale (CPSS) scores for identifying ischemic stroke in the emergency department (ED) and their association with decision delay.
METHODS: This prospective, cross-sectional validation study was conducted in a tertiary ED between August and November 2025. Secondary CPSS scores were independently assigned by two blinded emergency physicians using the three-item CPSS, based on structured interviews with untrained witnesses of stroke-like patients. Predictive validity was assessed using final ED diagnoses, and decision delay was derived from standardized prehospital timelines. Statistical analyses included Cohen’s kappa, diagnostic accuracy metrics, and chi-square tests.
RESULTS: A total of 235 patient–witness pairs were included. More than 70% of witnesses delayed action for over 30 minutes, accounting for 56.3% of prehospital delay. Interrater reliability was substantial (κ = 0.788). Secondary CPSS scores showed low sensitivity and negative predictive value but high specificity and positive predictive value indicating limited rule-in utility. Scores ≥1 were not associated with shorter decision delay (p = 0.789).
DISCUSSION AND CONCLUSION: Secondary CPSS based on witness reports is reliably scored but has limited diagnostic accuracy and does not facilitate faster decision-making, limiting its utility as a standalone tool for prehospital stroke triage. Future studies should address cognitive barriers and improve witness response.

Keywords: Stroke, bystanders, risk assessment, decision making, predictive value of tests, emergency department.