A stroke occurs when the blood supply to the brain is disrupted, which can lead to long-term disability or death if not treated promptly. Signs of a stroke include sudden numbness or weakness on one side of the body, confusion, trouble speaking or understanding speech, blurred vision, loss of balance and coordination, and severe headaches with no known cause. If someone is suspected of having a stroke, it is crucial to immediately call emergency services for an ambulance to transport them to the hospital for treatment.