Predictive Value of Witness-derived Secondary Cincinnati Prehospital Stroke Scale Scores in Suspected Stroke

The Cincinnati Prehospital Stroke Scale (CPSS) is traditionally scored directly by a healthcare professional or a layperson who independently observes facial droop, arm weakness, and speech disturbance, constituting the primary CPSS score. In contrast, this study focuses on witness-derived secondary CPSS scoring, which is performed indirectly by an emergency physician who is blinded to the patient's physical examination findings and relies exclusively on symptom descriptions provided by witnesses of the patient's initial presentation. This prospective analytical cross-sectional study aims to evaluate the predictive accuracy of secondary CPSS scores obtained by emergency physicians through structured interviews with witnesses of suspected stroke cases. Interrater reliability will be assessed between secondary CPSS scores independently assigned by a senior emergency medicine resident and an attending emergency physician based on witness-reported symptom descriptions. Secondary CPSS scores will then be compared with final neuroimaging diagnoses (CT/MRI), which will serve as the diagnostic gold standard. The study will also investigate the association between physician-coded secondary CPSS scores, witness demographic characteristics, and delays in seeking emergency medical care. Research Questions 1. Are witness-derived secondary CPSS scores, as assigned by an emergency physician, a valid tool for predicting ischemic stroke? 2. Are witness-derived secondary CPSS scores of ≥1 associated with shorter recognition-to-action time (decision delay)? Research Hypotheses 1. Witness-derived secondary CPSS scores assigned by an emergency physician are a valid diagnostic tool for predicting ischemic stroke. 2. Witness-derived secondary CPSS scores of ≥1 are associated with shorter recognition-to-action time. A total of 235 stroke witnesses, including family members, friends, neighbors, or bystanders who observed the patient's initial symptoms and accompanied the patient to th