Types of Seizures

Doctor Checking a Form

What are the different types of seizures and syndromes?

With epilepsy, there are many different types of seizures and syndromes.  To determine what types of seizures you have and come up with a diagnosis, doctors first classify seizures into 3 seizure categories:

 

  1. Focal Onset Seizures – The seizure activity will start in one specific area of the brain.

  2. Generalized Onset Seizures – The seizure activity begins in both halves of the brain at the same time.

  3. Unknown Onset Seizures – when doctors cannot identify where the seizures are starting based on an EEG, they are given this classification.

What are Focal Onset Seizures?

Focal Onset Seizures – Can be divided into 2 categories


Focal Onset Aware Seizures, formerly known as Simple Partial Seizures.

  • With focal onset seizures, people can remain alert and aware of what is going on.

  • They can even talk or move normally, but something else is happening. 

  • Focal Onset Aware Seizures can be divided into 4 categories:

    • Autonomic – These affect areas of the brain responsible for involuntary functions and can cause changed in blood pressure, heart rhythm, or bowel or bladder function.

    • Motor – These affect muscle activity and cause involuntary jerking of an arm, the face, a foot, or another part of the body. The part of the body that is moving involuntarily can tell the epileptologist where in the brain the seizures are taking place.

    • Psychic – These seizures occur in areas of the brain that trigger emotions or memories of things that have already happened. This can cause the person to experience fear, anxiety, or déjà vu – the feeling that something has happened before.

    • Sensory – These can affect any of the five senses:

      • Seeing, tasting or feeling things that aren’t there.

      • Hearing clicking, ringing or a person’s voice who is not there.

      • Tingling or numbness on one side of the body

Focal Onset Impaired Awareness Seizures, formerly known as Complex Partial Seizures.

  • As the new name suggests, the person having the seizure is not aware of what is going on.

  • They start repetitive motions like picking at their clothes or lip smacking, become unaware of where they are and may begin wandering.

  • These seizures usually last between 1 – 2 minutes.

  • Often, people with this type of seizure can have a warning or aura to let them know that the seizure will be happening soon.

Sometimes the Focal Onset Seizures can turn into a Bilateral Tonic Clonic Seizure – formerly known as Secondarily Generalized Tonic Clonic Seizures.

  • First the person experiences a focal onset seizure described above that occurs in one area of the brain.

  • That focal onset seizure then spreads throughout the brain causing the person to fall onto the ground and shake uncontrollably.

What are Generalized Onset Seizures

Generalized Onset Seizures

Generalized Onset Seizures affect both sides of the brain. These occur without warning – meaning they will not have an aura before it.

  • Absence Seizures – The person stares into space for a very small amount of time – about 10 – 15 seconds.

    • Childhood Absence Epilepsy – usually begins in children between the ages of 4 -6 years old. Often, children can outgrow these.

    • Juvenile Absence Epilepsy – begins later and continues into adulthood. In adulthood, people who experienced Juvenile Absence Epilepsy may experience Bilateral Tonic Clinic Seizures.

  • Myoclonic Seizures – Cause a repetitive jerking motion in the arm, head or neck. This occurs on both sides of the body, and often take place in the morning.

    • Juvenile Myoclonic Epilepsy – The person experiences Myoclonic Seizures that develop between the ages of 10 – 19 in addition to Bilateral Tonic Clonic Seizures.

  • Tonic Seizures – The person experiences a sudden stiffness or tenseness in the arms or legs, which can cause the person to fall, or injure themselves in some way.

    • These are rare, often begin in childhood, and are usually associated with either Lennox-Gastaut Syndrome, a type of epilepsy, or rarely, multiple sclerosis.

  • Atonic Seizures – also known as Drop Attacks

    • a person’s muscles go limp, causing them to immediately and unpredictably fall, or drop, to the ground.

    • The person remains conscious.

    • The person doesn’t always fall. It depends on which muscles in the person’s body go limp.

  • Tonic-Atonic Seizures

    • The person first experiences a sudden muscle stiffness or tenseness.

    • Then, their muscles go limp.

  • Tonic Clonic Seizures - also known as Grand Mal Seizures

    • The person loses consciousness and fall to the ground.

    • Their muscles begin twitching or jerking.

    • This usually lasts for 1 - 3 minutes.

    • They may become incontinent due to increased pressure on the bladder and bowels.

    • After the seizure, the person will slowly regain consciousness.

    • The person may feel tired, confused, agitated, or sore. They may have a headache, and can sleep for an extended period of time.

What are Unknown Onset Seizures?

Unknown Onset Seizures

 

This is the term doctors use when they are not sure from where the seizures are originating. If no one has seen the seizure, and there was no seizure activity spotted on the first 30 minute to hour long EEG, doctors will use this term until they can get more detailed information.

Loved ones videoing the seizures with their phone, after making sure the person is safe from injury, can help doctors better determine if the seizures are focal or generalized. 

Unknown Onset Seizures – This is the term doctors use when they are not sure from where the seizures are originating. If no one has seen the seizure, and there was no seizure activity spotted on the first 30 minute to hour long EEG, doctors will use this term until they can get more detailed information.

Did You Know?

Epilepsy is characterized by loss of control because seizures are unpredictable

They can range from someone simply staring into space, or clenching their fist to becoming unconscious, falling down and having their entire body shake violently.

Did You Know?

Seizures vary from person to person.

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