Generally the first seizure occurs before the age of 12 months. It is a clonic seizure that is quite long lasting. It can either be initially generalised (affecting both sides of the body at the same time) or it can be said hemiclonic (affecting only one side of the body).
When the seizure is hemiclonic, it may also spread to the other side of the body, becoming generalised.
When a seizure exceeds 30 minutes, we speak of status epilepticus. Medical investigations including EEG recordings are usually normal at onset.
Within days, weeks or months after the first episode, seizures relapse and become repetitive.
Between the age of 12 and 18 months, clonic seizures are more frequent but shorter.
From about 1 to 5 years of age other types of seizures appear. Your child may experience these seizures anytime, day or night. They may be long-lasting and even turn into status epilepticus, leading sometimes to admission to intensive care units.
These seizures are:
Various external factors can set off all previously stated seizures. The triggering factors are described in details in Question 9. Your child’s neurologist will probably perform a prolonged EEG recording to better define this type of seizure. Even if a seizure does not occur during the EEG recording, the results are usually abnormal.
During this period, developmental delay becomes visible and will last until the end of childhood. There is also a risk of behavioural disturbances. Your child will probably experience cognitive and learning difficulties. However, the degree of these deficits is variable and neuropsychological testing can be a way to follow them. Language is always impaired, but very differently from one child to another. It can go from a total absence to a relatively structured speech making a conversation possible.
 Ages are indicated for information.
Clonic seizures (convulsions): More or less rapid jerky movements, repeated at more or less regular intervals.
Tonic-clonic seizures: The tonic phase comes first: all the muscles stiffen. Air being forced past the vocal cords results in a cry or groan. The person loses consciousness and falls down. The tongue or cheek may be bitten, and saliva melt with blood may come from the mouth. The face may turn a bit blue. After the tonic phase comes the clonic phase: The arms and usually the legs begin to jerk rapidly and rhythmically, bending and relaxing at the elbows, hips and knees. After a few minutes, the jerking slows and stops. Bladder or bowel control is sometimes lost as the body relaxes and the person may not retain urine or faeces. During this period he/she may need diapers. Consciousness returns slowly, and he/she may be drowsy, confused, agitated, or depressed. These seizures generally last 1 to 3 minutes. A tonic-clonic seizure that lasts longer than 5 minutes needs medical management.
Myoclonic seizures: Sudden, very brief movements, sometimes repeated, similar to “jerking” (physical reaction to being startled). They are generally of moderate intensity. Fever may increase their intensity and frequency.
Absence: Impaired consciousness, without convulsion. The child stops what he/she was doing, gets a vacant stare and becomes unresponsive. Generally lasting a few seconds but when longer, they can lead to a fall. They may pass unnoticed.
Prolonged seizure or status epilepticus: It is either a seizure lasting more than 20-30 minutes, or repeated seizures at brief intervals without a regain of consciousness in between.
Partial (focal) seizures: Starting in a small area of the brain, they are visible on EEG recordings. They have very different manifestations: muscle stiffening, breathing, sweating… Overall, these seizures are brief, lasting less than 2 minutes.