Sudden dizziness, double vision, loss of vision in one eye, or inability to touch one’s nose — all warrant calling 120 for stroke suspicion

No cost involved. Besides the three FAST signs — facial droop, arm weakness, and speech difficulty — two additional checks are recommended. First, ask the person to stand straight with eyes closed and see if they lose balance; then ask whether they see double or have blind spots. Second, have them extend a finger toward their nose, close their eyes, and repeat the motion.

The University of Kentucky Stroke Center in the United States reviewed 736 medical records of acute ischemic stroke (stroke caused by a blocked blood vessel) in 2014. Among them, 14.1% of patients presented with none of the three symptoms of facial drooping, arm weakness, or slurred speech (FAST) at the time of onset. By including 'unsteady gait, leg weakness, and visual symptoms' in the screening, the missed proportion decreased from 14.1% to 4.4%. Two hospitals in the United States reviewed 465 emergency medical records of ischemic stroke, and initially, 22% were overlooked. For blockages in the blood vessels supplying the back of the brain (posterior circulation stroke), 37% were initially overlooked, while for the front, it was only 16%. People who were dizzy were more likely to be missed, with an odds ratio of 1.99 compared to those who were not dizzy. For those with nausea and vomiting, the odds ratio was 4.02. In the stroke signals listed in the 2025 International Red Cross First Aid Guidelines, there are also 'sudden blurred vision in one or both eyes' and 'sudden difficulty walking, dizziness, loss of balance, or coordination'.

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；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；International Federation of Red Cross and Red Crescent Societies (2025). International First Aid, Resuscitation and Education Guidelines 2025，第 366–367 页：「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

Blockages in the blood vessels at the back of the brain (posterior circulation stroke) often do not involve facial drooping or hand paralysis, presenting only as vertigo, unsteady gait, or double vision, which is why they are most easily overlooked. Inaccuracy in pointing to the nose or inability to stand with eyes closed belongs to the 'problems with balance or coordination' mentioned in the Red Cross guidelines. However, no single movement can rule out a stroke: if symptoms appear suddenly and do not subside, call 120 and note the exact time of onset. That Kentucky study only reviewed records from one hospital, and the author explicitly stated that further verification is still required.