Understanding types of seizures
The two main categories of seizures are:
- Generalized seizures, which affect the entire brain
- Focal seizures (also called partial seizures), which affect one part of the brain
Within each category, there are different seizure types.
Generalized seizures
Absence seizures
Also called petit mal seizures, absence seizures mainly affect young people, typically between 4 and 12 years of age. These seizures are characterized by brief staring spells (typically lasting less than 15 seconds). During the seizure, the child may abruptly stop what they were doing. They'll then resume their activity just as abruptly and be unaware that anything happened. There are no major muscle convulsions, but you may observe movements, such as fluttering eyelids.
Absence seizures can occur several times a day. Because they're subtle, they may not be detected until the child's schoolwork is affected.
Atonic seizures
With this type of seizure, the child suddenly goes limp (atonic refers to a lack of muscle tone). Children may abruptly fall (called a drop attack) and be injured during an atonic seizure.
Myoclonic seizures
Myoclonic seizures cause one or more limbs or the trunk of the body to jerk quickly, as if being shocked by electricity. The seizures are brief but can occur repeatedly. The child remains conscious, unless the myoclonic seizure progresses into another type.
Clonic seizures
In a clonic seizure, muscles on both sides of the body convulse rhythmically. Infants are more likely to have clonic seizures than older kids.
Tonic seizures
During a tonic seizure, the muscles stiffen. The change in muscle tone can be gradual or sudden. The child usually stays conscious but may fall down.
Tonic-clonic seizures
Also called grand mal seizures, tonic-clonic seizures cause:
- Loss of consciousness
- Muscle stiffening
- Rhythmic muscle spasms
The child may cry out at the start of the seizure. During the seizure, they may collapse, lose bladder control, or bite their tongue or cheek. Afterward, they may feel very tired.
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Focal (partial) seizures
Simple focal seizure
During a focal seizure, the child may experience:
- Movements, such as twitching or stiffening
- Sensory symptoms, such as a strange taste or smell
- Peculiar memories or a feeling of déjà vu
- Unexplainable emotions, such as joy or sadness
They remain fully conscious during the seizure.
Complex focal seizure
This is the same as a simple focal seizure except the child's awareness is impaired. They may act confused or spaced out. They also may perform repetitive actions or movements, such as chewing, walking or fidgeting.
Secondarily generalized seizure
If a focal seizure evolves into a tonic-clonic (grand mal) seizure, it's known as a secondarily generalized seizure. These seizures begin in one side of the brain, then spread to both sides.
Types of seizures that occur only in children
Children can experience many types of seizures, but there are some that occur only in kids.
Febrile seizures
Febrile seizures are triggered by a fever. They are the most common seizure disorder in children and typically occur in kids who are 6 months to 5 years old. During a febrile seizure, the child loses consciousness and their arms or legs convulse or twitch rhythmically.
Febrile seizures don’t cause brain damage and are not considered to be a form of epilepsy.
Infantile spasms
Infantile spasms usually appear before children reach 1 year of age, typically in those who have a serious brain disorder.
During the seizure, the child will bend their neck and trunk forward and extend the arms and legs. The spasms are brief but may repeat in a series that lasts several minutes.
Stages of a seizure
Some people experience specific movements, feelings or sensations – called an aura – before a seizure starts. For example, the person may smell something strange or have a feeling of déjà vu. These symptoms are actually due to a simple focal seizure, which can be followed by a convulsive seizure.
The period between the seizure subsiding and the child returning to normal is called the postictal state. During this time, the child may experience certain symptoms, such as confusion; fatigue; headache; or weakness in a hand, arm or leg. The postictal state usually lasts 5 to 30 minutes, but it can extend to a few hours or days.
