If there is sudden spinning dizziness with unsteadiness, double vision, blackout in one eye, or the fingertip can't reach your own nose, treat it as a stroke and call 120 (China's ambulance number)

In a real emergency, call 911 first, then read this.

Cost

Free. Add two more checks to the three actions of "face, arms, speech" (§13.3, mouth suddenly drooping or speech slurred). One is to have the person stand straight with eyes closed and see whether they sway, then ask whether they see double or have a missing patch in their vision. The other, if you suspect a stroke, is to reach out and touch your fingertip to your nose, then close your eyes and do it again.

What you get

In 2014, the stroke center at the University of Kentucky in the United States reviewed the records of 736 acute ischemic strokes (stroke caused by a blocked vessel). Of these patients, 14.1% had none of the three symptoms of facial droop, arm weakness and unclear speech (FAST) at onset. When "unsteady walking, leg weakness and visual symptoms" were also counted in the screening, the share missed fell from 14.1% to 4.4%. Two U.S. hospitals reviewed the emergency records of 465 ischemic strokes, and 22% were missed at first. When the vessel supplying the back of the brain is blocked (posterior circulation stroke), 37% were missed at first, versus only 16% for the front. People with dizziness were about 1.99 times as likely to be missed as those without (odds ratio 1.99), and those with nausea and vomiting 4.02 times. The stroke signs listed in the 2025 first aid guidelines of the International Red Cross also include "sudden loss of vision in one or both eyes" and "sudden trouble walking, dizziness, or loss of balance or coordination."

Notes

When the vessel at the back of the brain is blocked (posterior circulation stroke), the mouth often doesn't droop and the hand isn't paralyzed. There may only be spinning dizziness, an unsteady walk and double vision, which is why it is the most easily missed. Missing the nose with the finger and being unable to stand with eyes closed fall under the "problems with balance or coordination" that the Red Cross guidelines mention. But no single check can rule out a stroke: if the symptoms come on suddenly and do not ease, call 120 and note the exact time they began. The Kentucky study looked only at the records of one hospital, and the authors themselves say it needs to be verified again.

Evidence grade

B : Supported by research but without a precise number, or based on small or single studies.

Sources

1. Aroor S, Singh R, Goldstein LB (2017). BE-FAST (Balance, Eyes, Face, Arm, Speech, Time): Reducing the Proportion of Strokes Missed Using the FAST Mnemonic. Stroke, 48(2), 479-481. https://doi.org/10.1161/STROKEAHA.116.015169
2. Arch AE, Weisman DC, Coca S, et al. (2016). Missed Ischemic Stroke Diagnosis in the Emergency Department by Emergency Medicine and Neurology Services. Stroke, 47(3), 668-673: "Thirty-seven percent of posterior strokes were initially misdiagnosed compared with 16% of anterior strokes". https://doi.org/10.1161/strokeaha.115.010613
3. International Federation of Red Cross and Red Crescent Societies (2025). International First Aid, Resuscitation and Education Guidelines 2025, pages 366–367: "Sudden trouble in seeing with one or both eyes" "Sudden trouble walking or experiencing dizziness, loss of balance or coordination". https://www.ifrc.org/sites/default/files/2026-03/IFRC%20International%20First%20Aid,%20Resuscitation%20and%20Education%20Guidelines%202025.pdf

Translated from the Chinese original. Original book, section 13, tip 4. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer