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Understanding Seizures -- the Basics

What Are Seizures?

A seizure occurs when there’s abnormal electrical activity in the brain. Seizures may go virtually unnoticed. Or, in severe cases, they may produce a change or loss of consciousness and involuntary muscle spasms called convulsions. Seizures usually come on suddenly and vary in duration and severity. A seizure may be a one-time event, or you may have seizures repeatedly. Recurrent seizures are called epilepsy, or a seizure disorder. Less than one in 10 people who has a seizure develops epilepsy.

Experts classify seizures into two general categories and many subtypes based on the pattern of the attack.

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Understanding Seizures -- Diagnosis and Treatment

To decide if your "spells" are seizures, your doctor will: Take a detailed medical history (including a family history of seizures). Gather information about your behavior before, during, and after the episode. It is very important to have someone with you who witnessed the episode and can describe it to the doctor. Do a physical exam These are tests that may be done: An electroencephalogram (EEG) to identify any abnormal electrical misfiring in the brain and help predict the ...

Read the Understanding Seizures -- Diagnosis and Treatment article > >

Generalized seizures involve both sides of the brain from the start of the attack. Common subtypes include tonic-clonic (grand mal) and absence seizures (petit mal). Febrile and infantile spasms are two types of generalized seizures that occur almost exclusively in young children.

Partial (or focal) seizures are the second major seizure type. These begin in a specific area of the brain and may be contained there. Or they may spread to the entire brain.

  • With simple partial seizures, the person remains conscious.
  • Complex partial seizures involve impaired consciousness.

What Causes Seizures?

Often the cause of a seizure is unknown. Many conditions can provoke seizures, including:

WebMD Medical Reference

Reviewed by Richard Senelick, MD on March 01, 2015

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