Neurosurgeons claim that if they are able to operate on a patient who’s suffered a stroke within 3 hours of it occurring, there is every chance that the person can make a recovery. But realizing someone is (or you are) having a stroke is not always straightforward for most of us who know little about medicine.

So here are some brief instructions to help you understand. We implore you to read them – you might just be able to save your own or someone else’s life one day.

How to understand that you are having a stroke

• Numbness in the left arm, leg, or the left side of the face.
• Trouble speaking and understanding other people’s speech.
• Complete or partial paralysis.
• Trouble seeing in one or both eyes.
• Dizziness and loss of consciousness.