Complex Partial Seizures
In these types of seizures a person’s consciousness is altered. This alteration of consciousness during a complex seizure does not mean the person falls to the floor but it does mean they will not remember the seizure or their memory of it will be distorted. However, to onlookers it may seem that the person is fully aware of what they are doing.
Complex partial seizures can take the form of ‘automatisms’ such as chewing and swallowing, repeatedly scratching the head or searching for an object. Some people may even undress. Occasionally, a person may wander off, recovering full awareness minutes or even hours later, unable to remember anything.
Complex partial seizures can spread to the rest of the brain. When this happens the resulting seizure is called a secondary generalised tonic-clonic seizure. If the spread of activity happens quickly it may appear to be a straightforward tonic-clonic seizure.
Simple Partial Seizures
The difference between complex partial and simple partial seizures is that, during simple partial seizures, the person remains conscious and fully aware. However, this does not mean that the person experiencing this type of seizure is able to stop or control the symptoms. Simple seizures can affect movement, emotion and sensations.
The electrical activity which causes a simple partial seizure is confined to one small part of the brain. What a person experiences during one of these seizures depends on which part of the brain is affected.
Tonic-Clonic Seizures
Tonic-clonic seizures are the most common form of generalised seizures. In a tonic-clonic seizure, the person loses consciousness, the body stiffens, and then they fall to the ground. This is followed by jerking movements. After a minute or two, the jerking movements usually stop and consciousness slowly returns.
Tonic Phase
This is the part of the seizure when the person goes stiff, because all the body’s muscles contract. The person may appear to cry out, because the muscles in the lungs contract and force air out. Breathing becomes irregular, resulting in a lack of oxygen in the lungs. This can cause the skin (especially around mouth) to look blue, a condition called cyanosis. Occasionally, the person may lose control of their bladder or bowels.
Clonic Phase
This phase of the seizure follows the tonic phase. This is when the limbs jerk, caused by the muscles contracting and relaxing in quick succession. During this period, the person may bite their tongue and the inside of their cheeks. It is not possible to stop the seizure and nobody should try to restrict the person’s movements – this could cause damage to their limbs.
Recovery
After a minute or so, the muscles relax and the person’s body goes limp. At this stage the person is deeply unconscious and nothing will rouse them. Slowly they will regain consciousness, but may be groggy and confused. Gradually they will return to normal, but may not be able to remember anything for a while. The person will not remember anything about the seizure when they come round and they will need time to recover. Recovery time varies from minutes to hours. Many people will have a headache and aching limbs, which may last for hours or days after the seizure.
Absence Seizures
Absence seizures are generalised seizures, affecting both sides of the brain at once. However, they do not affect the entire brain. This type of seizure usually affects children, most commonly beginning between the ages of six and twelve. It is very rare in adults.
During an absence seizure the child stops what they are doing, loses awareness of their surroundings and stares. It can appear to onlookers that they are daydreaming or switching off. However, the child cannot be alerted or woken up, because they are momentarily unconscious. Around half of children who have absences may also display other symptoms during the seizure, such as smacking their lips, chewing, swallowing repeatedly or fiddling with their clothes. Their eyelids may also flicker slightly.
When an absence is over, the child is unlikely to be aware of what has happened, but may have the feeling that they have ‘missed’ something. Most children do not feel tired or ill after this type of seizure. Absence seizures generally only last for a few seconds. They can happen several times a day. Some children may have hundreds of them during a day, although this is rare. However, if the seizures are very brief they can be difficult to spot.