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

Out of 736 stroke cases, 14.1% showed none of the classic FAST symptoms at onset — no facial droop, no arm weakness, no slurred speech. Relying solely on those three signs would miss many cases. Adding checks for unsteady gait, double vision, or inability to touch the nose reduces that omission rate to just 4.4%. Any sudden dizziness, double vision, or failure to touch one’s nose should prompt an immediate call to emergency services and precise timing documentation.

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.

In 2014, researchers at the University of Kentucky Stroke Center reviewed 736 cases of acute ischemic stroke. They found that 14.1% of patients exhibited none of the FAST indicators at the time of onset. When additional screening criteria — including gait instability, limb weakness, and visual disturbances — were incorporated, the proportion of missed diagnoses dropped to 4.4%.

Infarctions affecting the cerebellum or brainstem — known as posterior circulation strokes — often lack facial droop or limb weakness. Instead, they manifest as vertigo, gait deviation, double vision, or difficulty swallowing, which are frequently mistaken for cervical spine disorders, hypoglycemia, or benign paroxysmal positional vertigo. Inability to touch one’s nose or maintain balance with eyes closed are telltale signs of cerebellar involvement. However, no single test can definitively rule out stroke; any sudden onset of these symptoms demands immediate emergency care and accurate timing recording. This study relied on records from a single medical center, and the authors themselves acknowledge the need for further validation.

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