When most people imagine a seizure, they picture someone convulsing on the floor. While some seizures look like this, many types look different. Understanding different types of seizures helps you know how you can help.
There are two main types of seizures. Generalized seizures affect both sides of the brain. Focal seizures, also called partial seizures, only happen in one part of the brain. If we don’t know where a seizure started, then it’s “unknown onset.”
Experts use several words to describe how muscles can move during a seizure:
- Tonic: Stiff
- Atonic: Limp
- Myoclonic: Brief jerking
- Clonic: Sustained, rhythmic jerking
There are many types of seizures. Here are a few of the most common ones.
Generalized seizures often cause you to lose consciousness.
Tonic-Clonic (Grand Mal)
“Tonic” means that muscles turn stiff. “Clonic” means shaking or jerking.
This is the type of seizure most people have heard of. During this seizure, you might cry out, fall down, and jerk rhythmically. This is dangerous because you aren’t aware of safety hazards.
When you come to, you might feel confused. Your body expends lots of energy during a seizure, so you may feel exhausted.
Absence (Petit Mal)
During an absence seizure, you typically have limited or no awareness of what’s going on around you. It’s usually a short episode. Sometimes you have many of them in a short time.
There are a few types of absence seizures.
- Typical: no movement, or clonic movements in parts of the face
- Atypical: slumping over
- Myoclonic: lifting the arms or making other rhythmic jerks
- Eyelid myoclonia: fluttering eyelids
Absence seizures can be frustrating because you often miss what’s going on around you. Afterward, someone may tell you what happened.
Some kids who get absence seizures end up outgrowing them. Other times, the seizures continue into adulthood.
Tonic and Atonic Seizures
Tonic seizures make you stiffen up, while atonic seizures make you go limp. Both of these can cause “drop attacks.”
Drop attacks are quick episodes that make you fall. Unfortunately, this is very dangerous. You can’t catch yourself when it happens. You may get hurt badly if you fall in the wrong place.
Have you ever jerked while falling asleep? Or have you had a huge full-body shiver at a random time? That’s called “myoclonus.” It’s an involuntary twitching movement. There are several types and causes, some of which are harmless.
Myoclonic seizures also cause brief jerks. During a myoclonic seizure, you get sudden jerks in certain body parts. The head, neck, and arms are the most common places.
Usually, it only lasts a second or two. You might have several in a short period of time. Typically, you are awake and alert when it happens.
If it lasts over half an hour, it’s called “myoclonic status epilepticus.” Unlike grand mal seizures, the person might be half-awake, and there’s no rhythmic pattern.
Also, atonic (limp) seizures sometimes follow myoclonic seizures. Then it’s called a myoclonic-atonic seizure. Usually, this affects the head and limbs. It often causes a drop attack.
Focal seizures only happen in a part of the brain. The severity depends on how much of the brain is affected.
You’ll still be awake during a focal seizure. However, you might feel strange or confused.
Aware or Impaired Awareness
“Aware” seizures mean that you still know what’s going on, even if you can’t control your body.
On the other hand, “Impaired Awareness” seizures cause confusion. It’s hard to answer questions or follow directions.
Motor Onset Seizures
Since these are focal seizures, they only affect one muscle or a muscle group. Here are some possible effects:
- Paresis (weakness)
- Hyperkinetic (big movements like jumping or thrashing)
- Automatisms (repetitive movements like nodding, undressing, or repeating words)
Motor seizures can involve many types of movements. To learn more, check out the International League Against Epilepsy’s info on motor seizures.
Non-Motor Onset Seizures
Not all focal seizures cause movement. Some involve strange feelings or states of mind.
- Autonomic: pallor, flushing, breathing changes, nausea, or more
- Cognitive: trouble speaking or reading, memory impairment, dissociation, intrusive thoughts, or more
- Emotional: anxiety, sobbing, anger, joy, or bursts of laughter
- Sensory: hallucinations, hot-cold flashes, tingling, light-headedness, or more
These experiences can also be part of an “aura.” An aura is the start of a seizure in the brain. It can also act as a warning that you’re going to have a seizure. If you notice an aura, then you can take steps to protect yourself. You might lie down somewhere safe or call for help.
Sometimes “behavior arrest” also happens. This is rarer and hard to notice.
Secondary Generalized Seizures
These seizures start as focal seizures and turn into generalized ones.
Knowing the types of seizures helps you understand what’s going on.
If someone else has a seizure, your job is to keep them safe. Remove or place cushions against hard surfaces or sharp corners. Start a timer so you can call an ambulance if it lasts more than 5 minutes.
Despite myths of people swallowing their tongues, don’t put anything in or near their mouths. This won’t help, and it could hurt them or you. Instead, lay them on their side to help prevent choking.
When it’s over, be there for the person. They might have questions or need help. Offer to call a loved one for them.
Finding the Cause
Seizures themselves can have many triggers: flashing lights, stress, exhaustion, and more. Triggers vary from person to person. But knowing the trigger or type of seizure isn’t enough to diagnose someone. After all, there are dozens of types of epilepsy.
That’s why we at EpiFinder are working on an app to help narrow it down. The upcoming EpiFinder app will help you describe your symptoms to your doctor. Then it’ll help figure out the most likely types of epilepsy.
There’s still a lot we don’t know about epilepsy. By continuing to raise awareness and support research, we can help people who live with seizures.
by Jenna Breunig, with help from Amanda Munson