What Are the Different Types of Seizures?

Seizures are usually categorized into three types depending on their onset.

A seizure is a sudden change in the brain's normal electrical activity. During a seizure, brain cells fire uncontrollably than their normal rate, temporarily affecting the way a person behaves, moves, thinks or feels. Recurrent seizures are called epilepsy. Seizures are usually categorized into three types depending on their onset. They are:

• Unknown onset:

1. When the beginning of a seizure is not known, it is now called an unknown onset seizure.
2. A seizure could also be called an unknown onset if it is not witnessed or seen by anyone. For example, when seizures happen at night or to a person who lives alone.
3. Unknown onset seizures may later be diagnosed as a focal or generalized seizure.

• Generalized seizures: Generalized seizures are characterized by widespread electrical discharges on both sides of the brain. They are further divided into six types:

1. Tonic seizures: This seizure may cause a patient to fall or collapse. Body stiffening is usually noticed. Back, arm, and leg muscles are affected most often.
2. Clonic seizures: It usually affects the face, neck, and arms and may last for several minutes. It includes jerking, rhythmic muscle movements.
3. Tonic-clonic seizures/grand mal seizures: Most common type of seizure. They involve a loss of consciousness, stiffening of the body, and shaking or jerking, and sometimes, followed by loss of bladder or bowel control.
4. Myoclonic seizures: They are short and involve uncontrollable jerking, usually the arms and/or legs, and last for only a second or two.
5. Atonic seizures/drop attack seizures: This type of seizure may cause the person suffering to drop objects. Usually sudden collapsing is noted. It usually involves a sudden loss of muscle tone, a head drop, or leg weakening.
6. Absence seizures/Petit mal seizures: 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 years. It may resemble daydreaming. Subtle body movement may accompany the seizure.

• Partial seizures/Focal seizures: Usually begin in one side of the brain and fall into one of two groups:

1. Simple partial seizures: 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 a leg, or spontaneous sensory symptoms, such as tingling sensation, dizziness, and visioning flashing lights.
2. Complex partial seizures: They usually 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.

In simple partial seizures, patients retain awareness of their surroundings; during complex partial seizures, they lose awareness of their surroundings.