The Different Types Of Epileptic Seizures

Epilepsy is a neurological condition that involves seizures, which are sudden surges of disruptive electrical activity in the brain that affect how a person feels or acts for a brief period.

Symptoms of an epileptic seizure may include a blank gaze, as though you’re staring into space; confusion; uncontrolled erratic muscle spasms in the upper body, arms, and legs; and loss of consciousness.

If you have seizures, it’s important for your doctor to know what type of seizures you have to determine what medication (or in some cases, surgery) will work best.

Here's a rundown of the various types of epileptic seizures, and how we determine what kind someone is having.

All epileptic seizures can be divided into one of two types:

Focal seizure: If you think of a seizure as an electrical storm in the brain, a focal seizure means that the electrical storm starts in one specific area of the brain. Sometimes it stays in that area, but it can also spread to a larger area or even to the entire brain.

Generalized seizures: This type of seizure affects the entire brain all at once right from the beginning.

A common misconception, however, is that focal seizures are always small and generalized seizures are typically big. A focal seizure that spreads to involve the entire brain can progress to full body shaking and loss of consciousness. On the other hand, a type of generalized seizure known as an absence seizure might just look like someone is staring or spacing out for a few seconds.

Myoclonic seizures, which can either be focal or generalized, involve abrupt jerking movements of the body. They frequently occur with juvenile myoclonic epilepsy, which is a type of epilepsy that often starts in childhood or adolescence.

This type of seizure, which used to be called a grand mal seizure, can also be either focal or generalized. Tonic-clonic seizures are what people typically picture when they think of an epileptic seizure. They involve full body stiffening, eyes rolling back in the head, jerking movements of the arms and legs, a clenched jaw, and sometimes foaming at the mouth.

If someone is having a tonic-clonic seizure, the most important thing to do is get them to lie down on the floor or a soft surface away from any potentially dangerous objects and roll them onto their side. Never put anything in the person’s mouth since this can cause injury to their teeth or gums and may obstruct their breathing. Watch them carefully to make sure they’re breathing and call 911.

The test we use to determine what type of seizures someone is having is called an EEG (electroencephalogram), which involves placing several electrodes all over the head to measure the electrical activity of the brain.

We can sometimes figure out what type of seizures someone has just from looking at the resting activity of the brain, but there are times when we need to record an actual seizure to figure that out.

In cases when an initial 30 minute EEG doesn’t give us a clear enough answer, we move on to what’s called an ambulatory EEG, which means we place the electrodes on the person’s head and then send them home with a recording device for anywhere from 24 to 72 hours so we can measure their brain activity when they’re both awake and asleep for a much longer period.

If we’re still not sure even after someone completes an ambulatory EEG, we may decide to admit them to the hospital so we can try to record a seizure and understand what’s happening.

When we’re not able to make the diagnosis with testing, we will often rely on what the patient tells us about their seizure symptoms—either what they can describe themselves or what other people who witness it describe. Videos that family members, friends, or coworkers have taken of the person having a seizure can also help us make the diagnosis.

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