Stroke Assessment in the Field: Cincinnati, LAMS, and RACE Scales Compared

Time kills brain. That phrase gets repeated so often in EMS education that it risks becoming background noise. But the data behind it is staggering. During a large vessel occlusion stroke, the patient loses approximately 1.9 million neurons every minute that treatment is delayed. Every minute. The difference between a patient who walks out of the hospital and a patient who spends the rest of their life in a nursing facility can come down to the assessment and transport decisions the first crew on scene makes in the opening minutes of the call.

Your job as the prehospital provider is not to diagnose the type of stroke. It is to recognize stroke symptoms, determine the likely severity, and get the patient to the right facility as fast as possible. The assessment scale you use determines what information you can provide to the receiving facility, and in some systems, it determines where you transport the patient.

Let me walk through the major prehospital stroke scales, what each one tells you, and when to use which.

The Cincinnati Prehospital Stroke Scale

The Cincinnati Prehospital Stroke Scale, often called CPSS or the Cincinnati scale, is the most widely taught and most commonly used prehospital stroke screening tool. It evaluates three findings: facial droop, arm drift, and speech abnormalities.

For facial droop, ask the patient to smile or show their teeth. Normal is both sides of the face move equally. Abnormal is one side of the face does not move as well as the other or droops.

For arm drift, ask the patient to close their eyes and hold both arms straight out in front of them for 10 seconds. Normal is both arms move equally or not at all. Abnormal is one arm drifts downward compared to the other.

For speech, ask the patient to repeat a simple phrase such as "You can't teach an old dog new tricks." Normal is the patient uses correct words with no slurring. Abnormal is slurred speech, wrong words, or the patient is unable to speak.

If any one of these three findings is abnormal, the patient screens positive for stroke. The Cincinnati scale has good sensitivity for detecting stroke, meaning it catches most strokes when they are present. However, it was designed as a screening tool, not a severity tool. It tells you "this is probably a stroke" but it does not tell you how severe the stroke is or whether it is likely a large vessel occlusion.

This matters because the treatment landscape for stroke has changed dramatically in recent years. Patients with large vessel occlusions may benefit from endovascular thrombectomy, a procedure that is only available at comprehensive stroke centers. A patient with a small stroke may do well at a primary stroke center, but a patient with a large vessel occlusion needs to go to a facility that can perform thrombectomy. The Cincinnati scale alone cannot make that distinction.

The NHTSA at nhtsa.gov publishes EMS education guidelines and assessment resources that include stroke recognition protocols. Their National EMS Education Standards provide the framework for how stroke assessment is taught in EMT and Paramedic programs across the country.

The Los Angeles Motor Scale (LAMS)

The Los Angeles Motor Scale, or LAMS, adds a level of severity assessment to stroke screening. It evaluates three motor findings and assigns a numerical score to each.

Facial droop is scored as 0 for absent and 1 for present. Arm drift is scored as 0 for absent, 1 for drifts down, and 2 for falls rapidly. Grip strength is scored as 0 for normal, 1 for weak, and 2 for no grip.

The total LAMS score ranges from 0 to 5. A score of 4 or higher has been shown to correlate with large vessel occlusion, meaning these patients are more likely to benefit from endovascular thrombectomy and should ideally be transported to a comprehensive stroke center.

LAMS is quick to perform, adds only the grip strength component to what you are already assessing with the Cincinnati scale, and gives you a numerical score that you can communicate to the receiving facility. "LAMS score of 4" tells the stroke team something specific about the likely severity of the event.

The advantage of LAMS over Cincinnati is that severity stratification. The disadvantage is that it only assesses motor deficits. Strokes that primarily affect speech, vision, or sensation without significant motor findings may score low on LAMS despite being clinically significant.

The Rapid Arterial Occlusion Evaluation (RACE)

The RACE scale is the most comprehensive of the three scales discussed here. It evaluates five components: facial palsy, arm motor function, leg motor function, head and gaze deviation, and aphasia or agnosia depending on which hemisphere is affected.

Facial palsy is scored 0 to 2. Arm motor function is scored 0 to 2. Leg motor function is scored 0 to 2. Head and gaze deviation is scored 0 to 1. Aphasia, tested when the right side of the body is affected indicating left hemisphere involvement, or agnosia, tested when the left side is affected indicating right hemisphere involvement, is scored 0 to 2.

The total RACE score ranges from 0 to 9. A score of 5 or higher has shown good predictive value for large vessel occlusion.

RACE provides the most detailed assessment of the three scales. It accounts for non-motor findings like gaze deviation and language or perceptual deficits, which the other scales miss. This makes it more sensitive for detecting strokes that primarily affect cortical functions.

The trade-off is complexity. RACE takes longer to perform and requires the provider to understand the difference between aphasia and agnosia and how to test for each. Aphasia is a language deficit: the patient cannot speak, cannot understand speech, or both. Agnosia is a perceptual deficit: the patient neglects or is unaware of one side of their body or environment. Testing for agnosia can be done by asking the patient to identify both arms as their own or by assessing for visual neglect.

Which Scale Should You Use

The answer depends on your system's protocol and your level of training. Here is my recommendation.

Every provider should be able to perform the Cincinnati Prehospital Stroke Scale. It is fast, easy, and catches most strokes. If your system uses Cincinnati as the standard screening tool, that is fine for initial recognition.

If your system has both primary stroke centers and comprehensive stroke centers in your transport area, you need a severity scale in addition to Cincinnati. Either LAMS or RACE will give you the additional information needed to make a transport destination decision. LAMS is simpler and faster. RACE is more comprehensive and slightly more accurate for predicting large vessel occlusion.

Know your system's stroke protocol. Some EMS systems have adopted specific scales by protocol and have transport algorithms that direct you to bypass closer primary stroke centers in favor of comprehensive stroke centers when the severity score exceeds a threshold. If your system has such a protocol, know the scale and the threshold cold.

Beyond the Scale: Critical Assessment Points

Regardless of which scale you use, several pieces of information are critical for stroke care and must be documented and communicated.

Time of symptom onset, or last known well time, is arguably the most important piece of information you can provide. Thrombolytic therapy with tPA has a treatment window that is time-dependent. Endovascular thrombectomy has a longer window but is still time-sensitive. "Last known well" refers to the last time the patient was observed to be at their normal baseline. This might be different from when symptoms were first noticed.

If the patient woke up with symptoms, the last known well time is when they went to bed or were last seen normal, not when they woke up. This distinction can mean the difference between a patient qualifying for treatment or being outside the window.

Blood glucose level is essential. Hypoglycemia can mimic stroke symptoms perfectly. Check a blood glucose on every patient with neurological deficits. If the glucose is low, correct it and reassess. You do not want to activate a stroke team for a patient who just needs dextrose.

Current medications, specifically blood thinners, are critical information for the receiving facility. Patients on anticoagulants like warfarin, apixaban, rivarelbaxaban, or dabigatran have different risk profiles for thrombolytic therapy. Get a medication list or bring the medication bottles to the hospital.

Document your neurological findings with times. Stroke symptoms can evolve during transport. If arm drift was present on initial assessment but resolved by hospital arrival, the stroke team needs to know it was present earlier. Serial assessments during transport provide the receiving team with valuable information about the trajectory of the event.

First Due Co. builds the clinical reasoning skills that help you recognize time-critical emergencies and make the right decisions under pressure. From stroke assessment to cardiac emergencies, our scenario-based EMS training prepares you for the calls that matter most. Start training at firstdueco.com.