The signs of a stroke

Photo of a woman making an emergency call

A stroke is a medical emergency. The most important thing you can do if you think someone is having a stroke is to immediately make an emergency call (112 in Germany and many other countries, 911 in the U.S.). The earlier you act, the more likely it is that lasting damage will be prevented.

Quick action can save lives in an emergency! Starting treatment for a stroke as soon as possible can stop brain cells from dying and prevent serious consequences.

It is important to recognize the typical signs of a stroke

  • Sudden weakness, numbness and signs of paralysis: People who are having a stroke can often no longer move their arm, hand and/or leg properly. As well as weakness, some people experience sensations like tingling and numbness. It can sometimes feel like your arm or foot has gone to sleep. Drooping on one side of the mouth is another typical sign of a stroke. These symptoms usually just affect one side of the body, and only rarely both sides.
  • Speech and language problems: Many people suddenly have difficulties finding the right words during a stroke and speak in broken sentences. Sudden slurring of words or mumbling can also be signs of a stroke. Another possible sign of a stroke is difficulties understanding speech – although the person can hear the words, they can't make sense of them.
  • Vision problems: A stroke can affect vision. The person can no longer see things on one side of them – their field of vision on the left or right is limited. They might also be unable to see at all through one eye for a while. Many people have double vision. If they want to reach for something, such as a cup, they often miss it.
  • Dizziness and trouble walking: People may have difficulty keeping their balance. They either feel like everything is spinning around, or swaying from side to side.
  • Severe headache: A sudden, unusually strong headache can also be a sign of a stroke. These headaches are normally caused by bleeding in the brain due to a torn or burst blood vessel. Headaches may be the only symptom at first, followed a little later by other symptoms such as paralysis and confusion. Nausea and vomiting are also possible symptoms.

What information do the emergency services need?

Someone who is having a stroke often can't speak or will have trouble communicating. So if you call the emergency services (122 in Germany and many other countries, 911 in the U.S.), it's important to be able to describe the symptoms and exact circumstances in as much detail as possible. Apart from the person's name, age and location, the main information they need is:

  • When did the symptoms begin?
  • Which symptoms did they have and how did they go on to develop?
  • Are they currently taking any medication?
  • Do they have any known cardiac arrhythmias (heart rhythm problems), in particular ?
  • Have they had similar symptoms or perhaps even a stroke before?

Remember: A stroke is a medical emergency. Do not hesitate to call for an ambulance. Waiting to see if the symptoms go away again on their own could waste precious time.

The necessary tests and treatments are only available in hospitals. And nobody will blame you if it turns out to be a false alarm.

Deutsche Gesellschaft für Allgemeinmedizin und Familienmedizin (DEGAM). Schlaganfall (S3-Leitlinie). AWMF-Registernr.: 053-011. 2020.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on January 31, 2023

Next planned update: 2026


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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