Types of Seizures

Although there are many types of seizures, those that people with epilepsy experience commonly fall into two major groups:

Generalized Seizures

Generalized seizures are characterized by widespread electrical discharges in both sides of the brain. You might think of it as a lightning storm in which the lightning seems to be coming from all areas of the sky at the same time.

There are six types of generalized seizures:

  • Tonic-clonic seizures, also known as grand mal seizures, are what most people think of when they imagine a seizure. They involve a loss of consciousness, stiffening of the body, and shaking or jerking, sometimes followed by loss of bladder or bowel control.
  • Tonic seizures include body stiffening, but do not include the clonic phase of uncontrolled jerking or spasms. Back, arm, and leg muscles are affected most often. The seizure may cause a patient to fall or collapse.
  • Clonic seizures include jerking muscle movements that are more rhythmic than chaotic. The muscle spasms typically affect the face, neck, and arms, and they may last for several minutes.
  • Absence seizures are also known as petit mal seizures. When people experience an absence seizure, they may seem to disconnect from the world, blank out, or stare into space for at least a few seconds. Their eyes may roll as well. People who have absence seizures usually lose awareness for a short time and have no memory of the seizure afterward. This type of seizure usually begins between the ages of 4 and 14, and it can resemble daydreaming. Subtle body movement may accompany the seizure, but it’s not the jerking movements that occur with tonic-clonic or clonic seizures.
  • Myoclonic seizures are typically short and involve uncontrollable jerking, usually of the arms and/or legs, and last for only a second or two.
  • Atonic seizures, also known as drop attacks, drop seizures, or akinetic epileptic drop attacks, may involve a sudden loss of muscle tone, a head drop, or leg weakening. People suffering an atonic seizure may suddenly collapse. This type of seizure may also cause the person suffering it to drop objects.

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Partial Seizures

Partial seizures, also known as focal seizures, begin in one side of the brain. They fall into one of two groups:

  • Simple partial seizures (also known as simple focal seizures) may only include the aura. During this type of seizure, awareness, memory and consciousness remain intact. This type of seizure may alter emotions or change the way things look, smell, feel, taste or sound. It may also result in involuntary jerking of a body part, such as an arm or leg, or spontaneous sensory symptoms, such as tingling, dizziness and flashing lights.
  • Complex partial seizures (also known as psychomotor seizures) alter consciousness or responsiveness. The person having the seizure may appear to be staring into space or moving without purpose. Some common movements include hand rubbing, chewing, swallowing, and repetitive motion, such as bicycling leg movements or walking in a circle.

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