What is Lennox-Gastaut syndrome (LGS)?

Answer

Lennox-Gastaut syndrome (LGS) is a childhood (onset, age 3–5 y) epileptic encephalopathy that manifests with atonic seizures, tonic seizures, and atypical absence seizures associated with mental retardation and a characteristic electroencephalographic (EEG) pattern. Infantile spasms and West syndrome frequently transform into Lennox-Gastaut syndrome. However, unlike West syndrome, Lennox-Gastaut syndrome tends to be a lifelong epileptic encephalopathy.

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Media Gallery

Electroencephalogram demonstrating hypsarrhythmia in infantile spasms. Note the chaotic high-amplitude background.
Electroencephalogram demonstrating hypsarrhythmia. Note the electrodecremental response that is associated with a spasm in infantile spasms (ie, West syndrome).
Slow (< 2.5 Hz) electroencephalographic spike and wave discharges associated with atypical absence seizures (ie, Lennox-Gastaut syndrome).
Slow (< 2.5 Hz) electroencephalographic spike and wave discharges in atypical absence epilepsy (ie, Lennox-Gastaut syndrome).
Typical 3-Hz electroencephalographic spike and wave discharges seen in absence epilepsy.
Electroencephalogram demonstrating absence epilepsy. Anteriorly dominant, typical 3-Hz spike and wave discharges.
Benign rolandic epilepsy associated with typical centrotemporal electroencephalographic spikes.
Electroencephalogram demonstrating benign rolandic epilepsy. Note the characteristic spike and waves seen in drowsiness.
Electroencephalogram demonstrating polyspike and wave discharges seen in juvenile myoclonic epilepsy.
Electroencephalogram demonstrating polyspike and wave response produced by photic stimulation.
Electroencephalogram demonstrating polyspike and wave discharges, which can be seen in idiopathic generalized epilepsy.
Electroencephalogram demonstrating paroxysmal fast activity as can be seen in Lennox-Gastaut syndrome.
Electroencephalogram demonstrating interictal pattern (sharp waves) in left temporal lobe epilepsy.
Electroencephalogram demonstrating interictal pattern of independent left and right temporal sharp waves, which can be seen in temporal lobe epilepsy.
Electroencephalogram demonstrating a left temporal lobe seizure (beginning) with 2-3 Hz rhythmic delta activity.
Electroencephalogram demonstrating a left temporal lobe seizure (middle), evolving to rhythmic theta activity.
Electroencephalogram demonstrating a left temporal lobe seizure (end), further evolving to diffuse delta activity prior to abrupt cessation.
Electroencephalogram of a right occipital lobe seizure (beginning); 4-5 Hz repetitive sharp waves (maximal T6/O2).
Electroencephalogram demonstrating spike-wave complexes as can be seen in idiopathic generalized epilepsy.
Electroencephalogram demonstrating right temporal lobe seizure (beginning); rhythmic delta activity evolving to rhythmic theta activity over the right temporal region.
Electroencephalogram demonstrating a right temporal lobe seizure (middle); continued right temporal rhythmic theta activity.
Electroencephalogram demonstrating a right temporal lobe seizure (end), resolution of right temporal rhythmic theta.
Electroencephalogram demonstrating interictal pattern of extratemporal spikes (left hemispheric spike and wave).
Electroencephalogram demonstrating interictal pattern of extratemporal spikes (right posterior spikes, temporoparietal).
Electroencephalogram demonstrating interictal pattern of extratemporal spikes (left posterior spikes, temporoparietal).
Electroencephalogram demonstrating repetitive central spikes (maximal Cz).
Electroencephalogram demonstrating repetitive central sharp waves (maximal Cz).
Electroencephalogram demonstrating repetitive left frontocentral sharp waves (maximal Cz).
Electroencephalogram demonstrating a left fronto-central seizure (beginning); rhythmic 14-16 Hz activity (maximal Cz and C3).
Electroencephalogram demonstrating a left fronto-central seizure (end); evolution to rhythmic 11-12 Hz activity with slightly higher amplitude with abrupt cessation.
Electroencephalogram demonstrating a right frontal lobe seizure (beginning); rhythmic 2-3 Hz activity (maximal Fp2).
Electroencephalogram demonstrating a right frontal lobe seizure (maximal Fp2) (end).
Electroencephalogram demonstrating a right frontal lobe seizure (beginning); repetitive ~3 Hz sharp waves (maximal F4/F8).
Electroencephalogram demonstrating a right frontal lobe seizure (middle); repetitive ~3 Hz sharp waves (maximal F4/F8).
Electroencephalogram demonstrating a right frontal lobe seizure (end); rhythmic sharply contoured ~2 Hz bi-frontal delta activity.
Electroencephalogram of a right occipital lobe seizure (middle); repetitive sharp waves evolve to rhythmic theta in the right occipital region.
Electroencephalogram of a right occipital lobe seizure (end); obscured by EMG artifact.
Electroencephalogram demonstrating a run of generalized polyspikes, which are more left predominant and can be seen in idiopathic generalized epilepsies.
Typical absence seizure with 3-4 Hz rhythmic generalized spike and wave discharges with abrupt onset and end.
Electroencephalogram demonstrates bilateral repetitive occipital sharp waves ~1Hz frequency.

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Author

Raj D Sheth, MD Chief, Division of Pediatric Neurology, Nemours Children's Clinic; Professor of Neurology, Mayo Clinic Alix School of Medicine; Professor of Pediatrics, University of Florida College of Medicine

Raj D Sheth, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Pediatrics, American Epilepsy Society, American Neurological Association, Child Neurology Society

Disclosure: Nothing to disclose.

Coauthor(s)

Amanda R Pennington, MD, PhD, MSc Fellow in Clinical Neurophysiology-Epilepsy, Department of Neurology, University of South Florida Morsani College of Medicine

Amanda R Pennington, MD, PhD, MSc is a member of the following medical societies: American Academy of Neurology

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Norberto Alvarez, MD Assistant Professor, Department of Neurology, Harvard Medical School; Consulting Staff, Department of Neurology, Boston Children's Hospital; Medical Director, Wrentham Developmental Center

Norberto Alvarez, MD is a member of the following medical societies: American Academy of Neurology, American Epilepsy Society, Child Neurology Society

Disclosure: Nothing to disclose.

Chief Editor

Selim R Benbadis, MD Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, Tampa General Hospital, University of South Florida Morsani College of Medicine

Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, American Medical Association

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Bioserenity (DigiTrace), Brain Sentinel, Cavion, Ceribell, Eisai, Greenwich, LivaNova, Neuropace, SK biopharmaceuticals, Sunovion<br/>Serve(d) as a speaker or a member of a speakers bureau for: Bioserenity (DigiTrace), Brain Sentinel, Cavion, Ceribell, Eisai, Greenwich, LivaNova, Neuropace, SK biopharmaceuticals, Sunovion<br/>Received research grant from: LivaNova, Greenwich, SK biopharmaceuticals, Takeda,.

What is Lennox-Gastaut syndrome (LGS)?

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