Epilepsy is often used synonymously with the term “seizure disorders,” and means the same thing. Different types of epilepsy therefore can include different types of seizures.
The two main types of epilepsy are focal and generalized. In focal epilepsy, seizure activity begins in one part of the brain. In generalized epilepsy, seizures begin on both sides of the brain at the same time. Therefore the main difference between the two types is where the seizure begins.
These types of epilepsy are further divided into subtypes, based on the signs and symptoms a person experiences. People with epilepsy can have multiple seizure types, but most experience only one or two types.
Focal seizures are the most common type of seizures. They begin in one part of the brain, and their symptoms depend on what part of the brain they affect.
Doctors diagnose focal seizures in both children and adults. About 60% of those with epilepsy have focal seizures.
Symptoms of focal seizures depend on what part of the brain is affected. They can include:
- A feeling of déjà vu (like the moment has happened before).
- Sudden changes in smell or taste.
- Hearing or seeing things that aren’t there (hallucinations).
- An intense feeling of fear, joy, anger, or sadness.
- Stiffness or twitching in one part of the body (such as the arm or face) or on one side of the body.
- Rapid heart rate.
- Grabbing at air or clothes.
- Numbness or tingling in one part or one side of the body.
There are 3 sub-types of focal seizures:
Focal aware seizures
In this type of seizure, the person is fully conscious and aware of symptoms.
Focal impaired awareness seizures
These seizures affect a bigger part of the brain than focal aware seizures. With this type of seizure, the person may be confused and unaware of their surroundings or situation.
Focal-to-bilateral tonic-clonic seizures
For some people with epilepsy, a focal seizure progresses to when the focal seizure activity spreads to include both sides of the brain. Focal-to-bilateral tonic-clonic seizures may look like generalized onset, so it’s important to know what part of the brain the seizures are starting in. Focal-to-bilateral tonic-clonic seizures may have different treatment options than generalized onset seizures.
If a person remains aware of their initial symptoms (mentioned above) sometimes this can give them time to get to a safe place before loss of awareness or progression to a bilateral tonic-clonic seizure occurs, which can prevent falls and injuries.
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Generalized onset seizures
As the name suggests, generalized seizures affect the whole cortex of the brain, not just one specific area of the brain. Depending on the electrical activity, generalized seizures may involve intense convulsive movements. Or, in the case of absence seizures, they may be hardly noticeable to the person experiencing or witnessing them.
The sub-types of generalized seizures include the following:
This is the most common type of generalized epileptic seizure. They’re also known as grand-mal seizures.
When someone is having this type of seizure, they will typically fall to the ground and become stiff, followed by moving their arms and legs in a shaking or jerking way.
Tonic-clonic seizures can cause breathing to briefly stop or become erratic. They can also result in loss of bladder control. This type of seizure usually lasts 1 to 3 minutes, with potential for longer durations.
This sub-type of seizure occurs more often in children than adults. Because they usually only last a few seconds, absence seizures can go unnoticed. The person will stare off into space as if daydreaming.
Someone having an absence seizure may involuntarily flutter their eyelids, repeatedly move their jaw, smack their lips, or stop what they are doing briefly.
Generalized onset atonic seizures
Atonic seizures cause a loss of muscle tone. Someone having an atonic seizure may fall, their head may drop, or they may slump over. These seizures may also be called “drop seizures.” They may still be conscious, or they may lose consciousness.
Generalized onset tonic seizures
This type of seizure causes the muscle tone to increase. The muscles become stiff and rigid. Unlike tonic-clonic seizures, tonic seizures don’t involve jerking, twitching, or shaking.
Generalized myoclonic seizures
A generalized myoclonic seizure involves sudden muscle twitches and jerking for seconds or minutes. Unlike tonic-clonic seizures, myoclonic seizures don’t involve muscle stiffness before the movement.
What’s the Difference Between Epileptic and Non-Epileptic Seizures?
Not all seizures or symptoms that look like seizures are epileptic seizures. The key difference is that epileptic seizures are caused by abnormal electrical activity in the brain, whereas non-epileptic seizures are not. For instance, underlying psychological factors such as stress, anxiety, depression, and PTSD can trigger a non-epileptic seizure.
It can be difficult for individuals to pinpoint their type of epilepsy and symptoms of the seizure. This is because seizures could happen at night or away from other people.
Many people identify the type of epilepsy and symptoms only after several seizures. Neurologists can also conduct tests to help determine the type of epilepsy.
Life with Epilepsy
A good source of information for people living with epilepsy is the Epilepsy Foundation. This organization provides educational options, support services, and other resource lists (including transportation services information, help understanding health coverage, information about camps for kids with epilepsy, financial assistance, and more).
If you need a second opinion or more information on how to live your best life with epilepsy, contact the UPMC Comprehensive Epilepsy Center.
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