This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
What the ROSIER scale is for
Many patients who arrive in the emergency department with sudden neurological symptoms do not have a stroke. Seizures, fainting, low blood sugar, migraine and other conditions, called stroke mimics, account for a large share of suspected strokes. The ROSIER scale (Recognition of Stroke in the Emergency Room), published by Nor and colleagues in Lancet Neurology in 2005, helps emergency staff separate a likely stroke from a mimic quickly at the bedside.
How it is scored
First check the blood glucose. If it is below 3.5 mmol/L (63 mg/dL), treat the low sugar and reassess before scoring. Then add:
| Item | Points |
|---|---|
| Loss of consciousness or syncope | −1 |
| Seizure activity | −1 |
| New asymmetric facial weakness | +1 |
| New asymmetric arm weakness | +1 |
| New asymmetric leg weakness | +1 |
| Speech disturbance | +1 |
| Visual field defect | +1 |
The total ranges from −2 to +5. A score above 0 makes stroke likely. A score of 0 or less makes it less likely, but does not rule it out.
How accurate is it?
In the original study, a score above 0 had a sensitivity of about 93% and a specificity of about 83% for stroke. Guidelines in the UK recommend ROSIER in the emergency department. Before hospital, simpler tools such as FAST (face, arm, speech, time) are used to decide whether to call for help.
Example
A patient has a drooping face, a weak arm and slurred speech, with no loss of consciousness and no seizure: 1 + 1 + 1 = 3. Stroke is likely, and the stroke team should be called right away so that brain imaging and treatments such as thrombolysis or thrombectomy are not delayed.
Limits
- ROSIER does not separate an ischemic stroke from a brain hemorrhage. Only imaging can.
- Posterior circulation strokes, with dizziness, unsteadiness or double vision, can score 0.
- A transient ischemic attack whose symptoms have already resolved can score 0, yet still needs urgent assessment.
If you suspect a stroke outside a hospital, call 911 at once and note the time the symptoms started.