Stroke identification is a key step in acute ischemic stroke management. Our objectives were to prospectively examine the agreement between prehospital and hospital Modified National Institutes of Health Stroke Scale (mNIHSS) assessments as well as assess the prehospital performance characteristics of the mNIHSS for identification of large vessel occlusion strokes.Method: In this prospective cohort study conducted over a 20-month period (11/2016–6/2018), we trained 40 prehospital providers (paramedics) in Emergency Neurological Life Support (ENLS) curriculum and in mNIHSS. English-speaking patients aged 18 and above transported for an acute neurological deficit were included. Using unique identifiers, we linked the prehospital assessment records to the hospital record. We calculated the agreement between prehospital and hospital mNIHSS scores using the Bland-Altman analysis and the sensitivity and specificity of the prehospital mNIHSS.Results: Of the 31 patients, the mean difference (prehospital mNIHSS—hospital mNIHSS) was 2.4, 95% limits of agreement (−5.2 to 10.0); 10 patients (32%) met our a priori imaging definition of large vessel occlusion and the sensitivity of mNIHSS ≥ 8 was 6/10 or 0.60 (95% CI: 0.26–0.88) and the specificity was 13/21 or 0.62 (95% CI: 0.38–0.82), respectively.Conclusions: We were able to train prehospital providers to use the prehospital mNIHSS. Prehospital and hospital mNIHSS had a reasonable level of agreement and and the scale was able to predict large vessel occlusions with moderate sensitivity.

Modified NIHSS (National Institute of Health Stroke Scale) is a 11-item, 0- 31 point motor stroke deficit scale that was developed to assess stroke severity. Our objective was to test the performance of modified NIHSS (mNIHSS) for the detection of large vessel occlusion when used by paramedics. Methods: This is a prospective, cohort study that was conducted in a fire-based EMS agency in California, during a 20-month period (11/2016 - 6/2018). We trained 40 ALS-trained Paramedics in Emergency Neurological Life Support (ENLS) stroke curriculum and the AHA/ASA NIHSS certification program. Patients were eligible if they were over the age of 18 years, with acute neurological deficit consistent with suspected acute stroke. Non-English speaking or vulnerable patients were excluded. The paramedics obtained a stroke-specific history, completed the mNIHSS, and assessed for contraindications for acute stroke treatment. This data was linked with the hospital outcomes using unique identifiers. We calculated the test performance of mNIHSS and NIHSS in the emergency department for LVO using the gold standard CTA imaging. The reliability between paramedic and stroke team mNIHSS scores using a Bland-Altman plot. Results: Of the 31 patients, 10 (32.3%) had an LVO on CTA. Of the 10 with LVO, 6 had a mNIHSS of >6 and a test sensitivity of 60.0% (95%CI: 26.2-87.8) and a specificity of 57.1% (95%CI: 34.0-78.2). Of the 31 patients, paramedics and stroke neurologist scores differed by 0-2 points in 42% of patients, 3-4 points in 39% patients, and greater than 4 points in 19% patients. Conclusions: In a single-center study, mNIHSS had moderate sensitivity for LVO. Paramedics were able to complete a stroke scale with high reliability.