What are seizures?

Your brain is made of nerve cells that send electrical impulses back and forth to each other and to your body. These electrical impulses control voluntary actions, like walking and talking, but they also control involuntary actions like digestion and your heartbeat.

A seizure happens when an unusual flurry of abnormal electrical impulses briefly interrupts the normal electrical activity in part of your brain.

Types of seizures

There are different types of seizures. They happen based on which part of your brain was interrupted with the abnormal electrical activity. The different types include:

  • Focal or partial seizures – These happen on one side of your brain. You may notice strange smells or sounds, see an aura or have emotional changes before the seizure happens.
  • Generalized seizures – These involve both sides of the brain. Types of generalized seizures include:
    • Absence or petit mal seizures – These involve briefly losing consciousness and staring into space.
    • Grand mal seizures – These often involve muscle spasms and shaking all over the body.
    • Atonic or drop attack seizures – These involve a sudden loss of muscle tone. This can cause you to fall over or drop your head down suddenly.
    • Myoclonic seizures – These cause groups of muscles to twitch, jerk or spasm.

After a seizure, you may temporarily feel sleepy. You might have a headache or body aches, and you might have changes in your vision or have a hard time speaking normally. This is called the postictal period.

Causes of seizures

Several different conditions can cause seizures. One of the most common causes is epilepsy, but a stroke or brain tumor can also cause them. People with diabetes can be at risk for having a seizure if their blood sugar is too high. Having a high fever can also cause a seizure.

Diagnosis and testing for seizures

If you've had a seizure, or if you think you might have had one, your doctor may recommend that you have tests to learn what caused your symptoms. Tests might include blood tests, imaging tests (such as a CT scan or MRI) or a test called an electroencephalogram (EEG) to check the electricity in your brain.



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