What are the different types of generalized seizures?

Generalized seizures involve both sides of the brain. There is loss of consciousness after the seizure occurs. Types of generalized seizures include the following:

  • Absence seizures (also called petit mal seizures): These seizures are characterized by a brief altered state of consciousness and staring episodes. Typically, the person's posture is maintained during the seizure. The mouth or face may move or the eyes may blink. The seizure usually lasts no longer than 30 seconds. When the seizure is over, the person may not recall what just occurred and may go on with his/her activities, acting as though nothing happened. These seizures may occur several times a day. This type of seizure is sometimes mistaken for a learning problem or behavioral problem. Absence seizures almost always start between ages 4 and 12 years.
  • Atonic (also called drop attacks): With atonic seizures, there is a sudden loss of muscle tone and the person may fall from a standing position or suddenly drop his/her head. During the seizure, the person is limp and unresponsive.
  • Tonic: Stiffening or contraction in a fixed posture, often with abduction of the shoulders and partial flexion of the elbows; usual duration 10 to 20 seconds, but often cluster; electroencephalography (EEG) pattern of rapid, diffuse polyspikes, often following a slow wave.
  • Generalized tonic-clonic seizures (GTC or also called grand mal seizures): This seizure is characterized by five distinct phases that occur. The body, arms and legs will flex (contract), extend (straighten out) and tremor (shake), followed by a clonic period (contraction and relaxation of the muscles) and the postictal period. During the postictal period, the person may be sleepy, have problems with vision or speech and may have a bad headache, fatigue or body aches.
  • Myoclonic seizures: This type of seizure refers to quick movements or sudden jerking of a group of muscles. These seizures tend to occur in clusters, meaning that they may occur several times a day, or for several days in a row.

Different types of generalized seizures, which result in loss of consciousness and have an area of onset that is usually difficult to localize, include:

  • absense seizures (also known as petit mal seizures, occasionally confused with daydreaming)
  • myoclonic seizures (associated with jerking of muscles/extremities)
  • tonic seizures (stiffening of muscles and loss of consciousness)
  • clonic seizures (spasming and jerking of muscles with loss of consciousness)
  • tonic-clonic seizures (also known as grand mal seizures, which are a combination of tonic and clonic seizures)

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.