Seizures associated with LGS

The onset of Lennox-Gastaut syndrome (LGS) does not begin with a specific type of seizure. For young children when there is no known cause, LGS usually begins with a "drop attack" followed by other seizures.1 The names and specific signs of the different seizure types are listed below. Keep in mind that as your child grows from childhood to adulthood, the seizures he or she experiences may change.

Focal or generalized tonic (formerly tonic)2

Doctors don’t usually diagnose LGS unless the child is having focal or generalized tonic seizures.1,2 These seizures can show muscle stiffening, dilated pupils, and a change in breathing patterns. Focal or generalized tonic seizures usually last less than 20 seconds. Generally, muscles tighten (this can happen to a specific set of muscles, or most muscle groups at once), the eyes roll back, and pupils dilate.3 These seizures can cause faster heartbeats and a temporary stop in breathing.2,3 They occur most often during sleep and usually last 10 to 60 seconds.3

Focal or generalized atonic (formerly atonic)2

Focal or generalized atonic seizures Also called “drop attacks,” these seizures cause brief loss of muscle tone. Abrupt falls from these seizures are common. are also known as drop attacks.1,2 They cause head nods, loss of posture, and sagging at the knees.3 They are usually very brief, lasting between 1 and 4 seconds.3

Atypical absence

This is the second most common seizure associated with LGS.1 Atypical absences Seizures marked by staring spells and lack of response. The person having the seizure may blink or have a slight twitching at the lips. There may be some responsiveness. Staring spells can be difficult to spot, especially in the developmentally disabled. are characterized by a gradual onset and termination1 as well as staring, pauses in activity, and a lack of response.3 They are generally 5 to 30 seconds long.3


A period of jerking movements.4

Focal or generalized myoclonic (formerly myoclonic)2

Focal or generalized myoclonic Sudden muscle jerks that last for only a second. Sometimes many will occur in a row. They can be quite strong and difficult to control. In people with LGS, these seizures often occur in the neck, upper arms, and shoulders. They can also occur in the face. seizures consist of sporadic jerks.2,4 They usually happen in the same way on both sides of the body.4

Partial, or focal onset

During partial or focal onset seizures, A type of partial seizure in which consciousness and ability to interact with the external environment are not impaired. The patient may experience visual hallucinations, localized tingling, emotional symptoms, and motor symptoms. a specific part of the brain does not work properly. Certain movements, emotions, sensations, and feelings can be affected.5

Generalized or unknown onset tonic clonic (formerly tonic clonic)2

In the first phase of generalized or unknown onset tonic clonic seizures, Formerly known as a "grand mal seizure", this type of seizure is what most people think of when they think of epilepsy. A tonic-clonic seizure usually begins with muscles tightening or locking up, often causing a fall. Unconsciousness follows, along with jerking of the limbs. After seizures stop, the person may experience confusion and fall asleep. Episodes last 1 to 3 minutes. the stiffening associated with tonic seizures occurs.2,4 It then gradually changes to the clonic phase, in which the muscles quickly switch between contraction and relaxation.4

Remember that LGS, just like other epilepsies, is more than seizures. Often, children with epilepsy have behavioral problems as well.1 And just as you need to understand the different types of seizures, you’ll need to understand the causes of behavioral problems and ways to approach them.

A child who has LGS may experience a number of different types of seizures.1
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  • 1. Arzimanoglou A, French J, Blume WT, et al. Lennox-Gastaut syndrome: a consensus approach on diagnosis, assessment, management, and trial methodology. Lancet Neurol. 2009;8:82-93.
  • 2. Shafer, PO. New terms for seizure classifications. Epilepsy Foundation Web site. Updated December 2016. Accessed November 26, 2019.
  • 3. Crumrine PK. Lennox-Gastaut syndrome. J Child Neurol. 2002;17(suppl 1):S70-75.
  • 4. Benbadis SR. Epileptic seizures and syndromes. Neurol Clin. 2001;19(2):251-270.
  • 5. Kiriakopoulos E, Shafer PO. Epilepsy Foundation Web site. Updated March 2017. Accessed October 21, 2019.