Types of Seizures
Seizures are caused by electrical disturbances in the brain. When most people hear the word "seizure," they tend to think of the "grand mal" type, which has dramatic outward signs. But, in fact, there are many different types of seizures:
Partial seizures (also called “focal seizures") originate on one side of the brain. Symptoms vary greatly, depending on which part of the brain is affected. A few signs of a partial seizure can include:
- Feeling tingling in part of the body
- Repeating sentences in a nonsensical way
- Hand fumbling movements
- Experiencing odd smells or tastes
- Jerking an arm or leg
- Appearing dazed and unaware of surroundings
- Lip/mouth movements
Partial seizures are divided into three categories:
- Simple Partial Seizures typically last less than one minute. Children remain alert, are aware that they are having a seizure at the time, and remember it afterward.
- Complex Partial Seizures typically last less than three minutes. Children are not aware they are having a seizure, and do not remember it.
- Secondarily Generalized Seizures start from one side of the brain, but the electrical disturbance spreads across the whole brain, resulting in a generalized tonic-clonic seizure, or “grand mal” seizure.
Generalized seizures involve both sides of the brain:
Absence Seizures cause children to stop, stare and be unresponsive for a few seconds. They may occur several times throughout the day, often without a child being aware of them. Absence seizures are most common between the ages of 4 and 12.
Myoclonic Seizures result in brief, jerking movements that can affect the whole body or a single limb. The movements may be subtle or very pronounced. Myoclonic seizures can occur several times a day. Typically they last less than 5 seconds, but can also occur in clusters, with repeated myoclonic seizures back-to-back.
Atonic Seizures cause children to suddenly lose muscle tone, go limp, and fall to the ground. They usually last for only a few seconds. The child will typically regain consciousness and alertness immediately following the seizure.
- As the seizure begins, children may yell or groan and fall to the ground.
- In the tonic or "stiffening" stage, they become rigid and may drool, clench their teeth, or bite their tongues. Breathing may appear to slow down or stop.
- In the clonic or "jerking" phase, the torso and limbs jerk. Breathing becomes shallow.
- When the jerking movements stop, children gradually regain consciousness, but are often very sleepy after the seizure.
- Most generalized tonic-clonic seizures last less than 2 minutes. Afterward, children are often tired, confused, and sometimes anxious.
Infantile spasms are a less common type of seizure disorder that typically starts when babies are between 4 and 8 months. Infantile spasms often occur when babies are waking up or falling asleep. A baby may have several spasms in a row, with quick, sudden movements of the head, arms, and legs.
It is important to start treatment for infantile spasms as soon as possible to minimize the risk of long-term complications.
Neonatal seizures occur in newborns. They can be subtle, with movements that may appear as:
- "pedaling" movements of the legs
- repetitive sucking or chewing
- repetitive blinking
- fixed staring
Or, they may be more pronounced, with jerking movements or muscle contractions. Only about 1 percent of all infants have neonatal seizures. Less than half will experience seizures later in life.
A febrile (or “fever”) seizure is usually a harmless event. These seizures are associated with fever in children 6 months to 5-years-old.
This is the most common type of seizure, occurring in 3 to 5 percent of children in the U.S. Febrile seizures tend to occur in families: A child with a sibling or parent who has had a febrile seizure is more likely to have one.
Only a small percentage of children who have a febrile seizure will develop epilepsy.
If a child has seizures with a fever, but also has seizures without a fever, this is not considered to be febrile seizures; this is considered to be epilepsy, or a seizure disorder.
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