Tonic and atonic seizures
In a tonic seizure the person’s muscles suddenly become stiff. If they are standing they often fall, usually backwards, and may injure the back of their head. Tonic seizures tend to be very brief and happen without warning.
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.
Information produced: September 2018
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.
These are the seizures that most people think of as epilepsy. the person becomes unconscious their body goes stiff and if they are standing up they usually fall backwards. they jerk and shake as their muscles relax and tighten rhythmically.
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.