What types of epileptic seizures are there?
There are various kinds of epileptic seizures. Among other things, this depends on the part of the brain involved and the size of the area affected. So what is an epileptic seizure? An epileptic seizure (also called an epileptic insult) is a seizure (attack or fit) caused by a sudden and temporary disturbance in the electrical activity of the brain.
Every epileptic seizure looks different. Some seizures cause a person to fall and/or lose consciousness. Some seizures cause a person's arms and legs to jerk or twitch. The person may also feel a tingling sensation, start staring or rolling their eyes.
Epileptic seizures can be roughly divided into 3 types, namely:
Focal onset seizures
Generalised onset seizures
Unknown onset seizures
Focal onset seizures
These seizures start a specific part of one hemisphere of the brain. The symptoms vary considerably, depending on where the disturbance occurs. The person may remain conscious (aware and alert), but they may also be less aware of what is happening around them or confused (impaired awareness). Focal onset epilepsy is the most common type, affecting over two-thirds of all people with epilepsy.
Generalised onset seizures
These seizures affect both sides of the brain at once or in rapid succession. The person will be temporarily unconscious and afterwards will not remember what happened during the seizure.
Unknown onset seizures
Contrary to the other seizures, it is not entirely clear where precisely in the brain these types of seizure start. Further examination is often necessary to shed more light on that.
Various types of epilepsy are described below.
Other names for this type of seizure are 'grand mal' and 'epileptic insult'. During these seizures, the person's muscles become rigid or jerk uncontrollably (tonic meaning muscular contraction, clonic meaning rhythmical jerking). While this is the best-known type of seizure, it is not the most common type. It is, nevertheless, the type of seizure that has the most impact on anyone witnessing it. The seizure progresses in phases.
The person may experience an aura before the seizure starts. An aura is a partial seizure that begins in a part of the brain. The person may experience specific symptoms such as a particular smell, a 'rising' feeling in their stomach, or flickering lights. Which symptoms occur is mostly determined by where in the brain the seizure begins.
The seizure begins with a tonic phase. This phase lasts around 30 seconds. During this phase, the person's body goes stiff, they stop breathing and their skin turns bluish. They then lose consciousness, fall down and start jerking and shaking violently. They will temporarily be unable to swallow, causing saliva to accumulate in their throat. People often bite their tongue or cheek due to sudden tightening of their jaw muscles, so there may be blood coming out of their mouth. Their heart rate will be irregular when the seizure starts and then faster than normal.
The clonic phase lasts a little longer, often between 0.5 and 1.5 minutes. During this phase, their muscles relax and tighten rhythmically, causing jerking movements of their arms, legs and face. They will gradually start breathing again, causing the accumulated saliva to be blown out of their mouth as foam.
The last phase can last up to a few minutes. The person will gradually stop jerking until they are completely relaxed. They will often be pale, and their breathing will be deep and noisy.
The seizure will generally be quite short. Most tonic-clonic seizures end within two to five minutes. However, the person will usually feel tired, confused or have a headache for a while afterwards. Many people also have aching muscles during this post-seizure period. The recovery time varies from person to person. Some people can function normally after 5 minutes or so, while others take a whole day or longer to recover. The seizures can occur during the day or at night, while the person is sleeping. The frequency of the seizures also varies from person to person.
A tonic seizure is similar to the stiffening phase of a tonic seizure. During a tonic seizure, the person loses consciousness and becomes rigid. One or more of their muscles suddenly tightens. If they are standing, they often fall, usually backwards. Muscle spasms characterise the tonic seizure. It can last from a few seconds to a few minutes. The person will usually recover from this type of seizure reasonably quickly.
Sudden, severe jerks characterise this type of seizure. Muscles in the arms and/or legs contract, sometimes in a single jerk, sometimes in series (happening in very close succession). These are also known as myoclonic clusters. As the jerks are so very brief, the level of awareness will not noticeably change. These seizures only last a short while, and the person recovers quickly after a seizure. Myoclonic seizures often occur early in the morning. In many cases, they are not recognised as epileptic seizures. A person may have these seizures for a very long time before they experience a major seizure and the doctor then diagnoses epilepsy. Generally speaking, these seizures can be well controlled with medication. They mostly occur during puberty.
In an atonic seizure, the person's muscles suddenly relax. They will collapse and may fall, usually forwards. Some people, therefore, wear helmets to avoid injury if they fall. The person will be unconscious for a few seconds. If they fall, they get up again straight away.
An absence seizure is one of the most subtle types of epileptic seizures. This type of seizure is also most common in primary school-age children. When a seizure occurs, the child will abruptly stop what they are doing. They become unresponsive for a few seconds, look blank and stare. Small movements might be noticeable such as fluttering eyelids, quivering chin or small head jerks. These seizures tend to last just a few seconds. These seizures can be well controlled with medication.
These seizures are most common in primary school-age children. The seizure starts with mouth twitching, as a result of which the child is no longer able to speak and starts dribbling. This may be accompanied by jerking muscles in their face, arms or legs. The child will often remain conscious. Benign rolandic epilepsy occurs primarily during the night or in the early morning.
Hypermotor seizures are characterised by complex, large-amplitude movements (in terms of size or strength) involving proximal body segments, which results in violent and inappropriate behaviour towards anyone near them.
What to do when someone has a seizure
If you see someone having a seizure, it is important to keep that person safe. This means providing first aid, administering their medication and calling for medical assistance if necessary. It is especially important to be alert to any dangerous situations that could arise during a seizure, such as a fall and/or injury.
Every seizure calls for a different approach and varies from person to person. Ask whether the person has epilepsy and what you can or should do if they have a seizure.
Read more tips/advice on what to do in the event of the different types of epileptic seizures here.
There are various ways of treating epileptic seizures. Most people with epilepsy are treated with medication. Epilepsy medicines don't cure the condition but they do suppress the risk of a seizure. That is why they are also known as anti-epileptic drugs or AEDs.
Which type of medicine is prescribed depends, among other things, on the type and frequency of the seizures, the type of epilepsy and the underlying cause. It will also vary from person to person. It is very important to examine how someone responds to the medication. This is because AEDs are known to have possible side effects. These include dizziness, a lack of energy, drowsiness and nausea. The drug aims to have as few seizures as possible with as few side effects as possible.
If the medication is not effective, or not effective enough, the person it concerns can be referred on to an epilepsy centre or its affiliated outpatient clinic. In the case of children, the specialised paediatric neurology department of a university hospital may also be consulted.
Can you prevent an epileptic seizure?
Other than taking their medication, there is nothing a person with epilepsy can do to prevent an epileptic seizure from happening. They can be alert to potential triggers and avoid them. Triggers are factors relating to a particular situation to the onset of a seizure. Examples of triggers include stress and a lack of sleep. You will find more triggers here. A person with epilepsy can also use one or more of the various epilepsy aids available. These aids help to avoid dangerous situations. The NightWatch may prove a solution for someone who has seizures during their sleep, for example.