What Are the Three Types of Seizures?

Reviewed on 4/22/2021

Seizures are caused by a sudden surge of abnormal electrical activity in the brain, which can affect how a person appears or acts, but for a short period of time. The types of seizures include generalized onset seizures, focal onset seizures, and unknown onset seizures.
Seizures are caused by a sudden surge of abnormal electrical activity in the brain, which can affect how a person appears or acts, but for a short period of time. The types of seizures include generalized onset seizures, focal onset seizures, and unknown onset seizures.

Seizures occur when there is a sudden surge of abnormal electrical activity in the brain that usually affects how a person appears or acts for a short time.

The three types of seizures include:

  • Generalized onset seizures
    • Both sides of the brain are affected at the same time
    • Includes seizure types like tonic-clonic, absence, or atonic 
  • Focal onset seizures
    • Focal seizures can start in one area or in one side of the brain
    • Focal onset aware seizures occur when a person is awake and aware during a seizure (formerly called simple partial seizure)
    • Focal onset impaired awareness seizures occur when a person is confused or awareness is affected during a focal seizure (formerly called a complex partial seizure)
  • Unknown onset seizures
    • Occur when the beginning of a seizure is not known, such as if it’s not witnessed by anyone
    • An unknown onset seizure may later be diagnosed as a focal or generalized seizure

What Are Symptoms of Seizures?

Symptoms of seizures may differ depending on the type. 

Symptoms of generalized onset seizures include:

  • Motor symptoms 
    • Tense or rigid muscles (tonic)
    • Sustained rhythmical jerking movements (clonic)
    • Muscle weakness or limpness (atonic) 
    • Brief muscle twitching (myoclonus)
    • Epileptic spasms (body flexes and extends repeatedly)
  • Non-motor symptoms (absence seizures) 
    • Staring spells
    • Brief twitches that can affect a specific body part or just the eyelids

Symptoms of focal onset seizures include:

  • Motor symptoms 
    • Tense or rigid muscles (tonic)
    • Jerking (clonic)
    • Muscle weakness or limpness (atonic) 
    • Brief muscle twitching (myoclonus)
    • Epileptic spasms (body flexes and extends repeatedly)
    • Repeated automatic movements (automatisms), such as clapping or rubbing of hands, lip smacking, chewing, or running
  • Non-motor symptoms
    • Changes in sensation
    • Mood changes
    • Changes in thinking or cognition
    • Changes in autonomic functions (such as gastrointestinal sensations, waves of heat or cold, goosebumps, heart racing, etc.)
    • Lack of movement (behavior arrest)

Symptoms of focal onset seizures include:

  • Motor seizures: either tonic-clonic or epileptic spasms
  • Non-motor seizures: behavior arrest

What Causes Seizures?

Causes of seizures can vary by age.

Causes of seizures in newborns include:

  • Intracranial bleeding
  • Lack of oxygen during birth
  • Low levels of blood sugar, blood calcium, blood magnesium or other electrolyte problems
  • Malformations of the brain
  • Maternal drug use 
  • Problems with metabolism

Causes of seizures in infants and young children include:

Causes of seizures in children and adults include:

  • Congenital conditions 
  • Genetics
  • Head trauma
  • Progressive brain disease (rare)

Causes of seizures in seniors include:

Common triggers that may precipitate seizures include:

QUESTION

If you have had a seizure, it means you have epilepsy. See Answer

How Are Seizures Diagnosed?

Tests used to diagnose the cause of seizures include: 

What Is the Treatment for Seizures?

Treatment for seizures usually involves medicines called anti-epileptic drugs (AEDs), such as:

Other treatments for seizures include: 

  • Diet therapy, including the ketogenic diet
  • Epilepsy surgery 
    • Removal of a small part of the brain that's causing the seizures 
    • Implantation of a small electrical device inside the body to help control seizures 

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Reviewed on 4/22/2021
References
https://www.epilepsy.com/