The fastest way to tell if someone is having a stroke is to watch for sudden changes in their face, speech, or ability to move one side of their body. These signs can appear in seconds and worsen over minutes to hours. Recognizing them quickly matters because clot-dissolving treatment works best within 4.5 hours of symptom onset, and every minute of delay increases the risk of permanent brain damage.
The BE-FAST Check
Healthcare professionals use the mnemonic BE-FAST to screen for stroke in both clinical and community settings. It covers six indicators:
- Balance: Sudden loss of balance or coordination, trouble walking, or dizziness that came on without warning.
- Eyes: Sudden blurred or double vision, or loss of vision in one or both eyes.
- Face: One side of the face droops or feels numb. Ask the person to smile. If the smile is uneven, that’s a red flag.
- Arms: One arm drifts downward when both are raised. Weakness or numbness on one side of the body is one of the most reliable stroke indicators.
- Speech: Slurred words, difficulty finding words, or speech that doesn’t make sense.
- Time: Note when symptoms started and call emergency services immediately.
You can test arm weakness more precisely with a simple technique neurologists use called the pronator drift test. Ask the person to hold both arms straight out in front of them, palms up, with their eyes closed. If one arm rotates inward and drifts downward, it suggests weakness caused by damage to the brain’s motor pathways. This is a fairly sensitive way to catch even subtle neurological deficits.
Hemorrhagic vs. Ischemic Stroke Symptoms
About 87% of strokes are ischemic, caused by a blood clot blocking flow to part of the brain. The rest are hemorrhagic, caused by a burst blood vessel bleeding into or around the brain. You can’t diagnose the type without a brain scan, but the symptoms do differ in ways that are worth knowing.
A sudden, explosive headache is the hallmark difference. In one study comparing the two types, 92% of patients with acute onset headache had a hemorrhagic stroke, while only 19% were in the ischemic group. Hemorrhagic strokes also more commonly cause seizures, agitation, and impaired eye movement. Ischemic strokes, by contrast, tend to develop more gradually over hours, and when headaches occur, they build slowly rather than hitting all at once.
Both types produce the classic one-sided weakness, speech problems, and facial drooping. The explosive “thunderclap” headache is what sets hemorrhagic stroke apart from the outside. But treatment decisions depend entirely on imaging, not on what the symptoms look like, which is why getting to a hospital fast matters regardless of the pattern.
Symptoms That Don’t Look Like a Stroke
Not everyone presents with textbook stroke signs. Women in particular are more likely to show up with symptoms that get mistaken for something else entirely. Research on gender differences in stroke presentation found that women more commonly experienced generalized weakness, mental status changes, fatigue, disorientation, and fever. Other non-traditional symptoms documented in women include nausea, chest pain, face or limb pain, feeling “odd,” and changes in behavior or level of consciousness.
These vague, whole-body symptoms can delay recognition. A woman having a stroke might look confused or exhausted rather than exhibiting the dramatic one-sided paralysis people expect. If any combination of these symptoms appears suddenly and without explanation, especially in someone with stroke risk factors like high blood pressure, diabetes, or a history of smoking, treat it as a potential stroke.
When Symptoms Disappear Quickly
Sometimes stroke symptoms show up and then vanish within minutes. This is called a transient ischemic attack, or TIA. A TIA typically lasts less than an hour, often just minutes, and leaves no permanent damage on its own. But it is a warning shot. Patients at higher risk based on clinical scoring can face up to an 8% chance of a full stroke within 48 hours. Even lower-risk patients still carry about a 1% chance in that same window.
The disappearance of symptoms does not mean the danger has passed. A TIA means something briefly blocked blood flow to the brain, and whatever caused it, whether a clot, narrowed artery, or heart rhythm problem, can do it again with worse results. Anyone who experiences stroke-like symptoms that resolve on their own still needs urgent evaluation.
Signs of a Past Stroke You Might Have Missed
Some strokes produce no obvious symptoms at all. These “silent” strokes, technically called silent brain infarcts, are surprisingly common and typically discovered incidentally on brain imaging done for another reason. A person might never know they had one.
But “silent” is somewhat misleading. A systematic review of over 11,000 participants found that silent brain infarcts were a significant factor in cognitive decline. People with these undetected strokes scored meaningfully lower on standard cognitive tests. The damage showed up as declines in specific areas of thinking, including memory, processing speed, and executive function. If you or someone you know has experienced a noticeable change in mental sharpness, trouble with memory, or difficulty with tasks that used to be easy, and there’s no clear explanation, a past silent stroke is one possibility worth investigating.
What Happens at the Hospital
The first thing the medical team needs to determine is whether the stroke is caused by a clot or by bleeding, because the treatments are opposite. A CT scan of the brain is the standard first step. CT is fast, widely available, and extremely accurate at detecting bleeding (100% specificity). Its weakness is that it catches only about 39% of ischemic changes in the early hours.
MRI is far more sensitive for confirming an ischemic stroke, detecting ischemia 99% of the time. It’s also better at spotting small strokes in areas the CT tends to miss, like the brainstem. However, MRI takes longer, is harder to perform on patients who are on monitors or ventilators, and isn’t safe for people with certain metallic implants. In practice, most emergency departments start with CT to rule out bleeding, then move to MRI if needed.
If the stroke is ischemic and the patient arrives within 4.5 hours of symptom onset, clot-dissolving medication can be given intravenously to restore blood flow. In some cases, patients who arrive between 4.5 and 9 hours, or who wake up with stroke symptoms, may still be candidates for treatment if brain imaging shows there is tissue that can still be saved. The core principle is the same: the sooner blood flow is restored, the less brain tissue is permanently lost. Reperfusion therapy is time-dependent, meaning every delay directly worsens outcomes for both survival and long-term disability.