Tonic clonic seizures (previously called grand mal)
These are the seizures most people think of as epilepsy. During a tonic clonic seizure a person jerks and shakes (convulse) as their muscles relax and tighten rhythmically.
At the start of the seizure the person becomes unconscious, their body goes stiff and if they are standing up they usually fall backwards. They may also cry out and they may bite their tongue or cheek.
During the seizure:
- they jerk and shake (convulse) as their muscles relax and tighten rhythmically
- their breathing might be affected and become difficult or sound noisy
- their skin may change colour and become very pale or bluish
- they may wet themselves.
After the seizure (once the jerking stops):
- their breathing and colour return to normal
- they may feel tired, confused, have a headache or want to sleep.
Focal to bilateral tonic-clonic seizure (previously called a secondarily generalised seizure)
Sometimes focal seizures spread from one side (hemisphere) to both sides of the brain. This is called a focal to bilateral tonic-clonic seizure.
When this happens the person becomes unconscious and will usually have a tonic clonic ('convulsive' or shaking) seizure. If this happens very quickly, they may not be aware that it started as a focal seizure.
Information produced: September 2018
Other types of seizure
In an atonic seizure (or 'drop attack') the person’s muscles suddenly relax and they become floppy. If they are standing they often fall, usually forwards, and may injure the front of their head or face. Like tonic seizures, atonic seizures tend to be brief and happen without warning. With both tonic and atonic seizures people usually recover quickly, apart from possible injuries.
Myoclonic means ‘muscle jerk’. Muscle jerks are not always due to epilepsy (for example, some people have them as they fall asleep). Myoclonic seizures are brief but can happen in clusters (many happening close together in time) and often happen shortly after waking.
Absence seizures are more common in children than adults and can happen very frequently. During an absence a person becomes unconscious for a short time. They may look blank and stare, or their eyelids might flutter. They will not respond to what is happening around them. If they are walking they may carry on walking but will not be aware of what they are doing.
In focal aware seizures (FAS), previously called simple partial seizures, the person is conscious (aware and alert) and will usually know that something is happening and will remember the seizure afterwards.
Focal impaired awareness seizures (FIAS) affect a bigger part of one hemisphere (side) of the brain than focal aware seizures. This seizure was previously called complex partial seizures.
In March 2017 the International League Against Epilepsy (ILAE), a group of the world's leading epilepsy professionals, introduced a new method to group seizures. This gives doctors a more accurate way to describe a person's seizures, and helps them to prescribe the most appropriate treatments.