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UK-NOTPR-1010 | April 2022



Lennox-Gastaut Syndrome

Understanding Lennox-Gastaut Syndrome

Lennox–Gastaut syndrome is a rare and severe form of epilepsy that emerges during childhood.1 It is named after the doctors who first described the condition.

Epilepsy and Lennox–Gastaut syndrome overview

Epilepsy is a brain disorder in which people experience ‘seizures’ – sudden surges of electrical activity in the brain. Seizures can vary from a brief lapse of attention or muscle jerk to a severe and prolonged convulsion.2,3 Some people with epilepsy have less than one seizure per year, whereas other people have several seizures per day.3

Different epilepsy ‘syndromes’ have been defined based on factors such as the type of seizures experienced, age at first seizure, and the part of the brain involved.4 People with Lennox–Gastaut syndrome experience several different types of seizure, which can make them stiffen, lose consciousness, or fall.1 Due to the severity of the seizures, as well as frequent injuries, developmental delays and behavioural problems, Lennox–Gastaut syndrome has serious health implications.1

Facts about Lennox Gastaut

Lennox–Gastaut syndrome is a rare and severe form of epilepsy that emerges during childhood.1 There are many different causes of Lennox–Gastaut syndrome, of which one is brain damage.1

The three key features of Lennox–Gastaut syndrome are multiple types of seizure, cognitive impairment, and abnormal electroencephalogram (EEG) features.1,3


A seizure is classified as either ‘generalised’ or ‘focal’, depending on whether it affects the whole brain or just a part of the brain. The following symptoms can occur during a seizure:5,6


  • Motor symptoms – rhythmical jerking movements (‘clonic’); muscles becoming weak or limp (‘atonic’); muscles becoming tense or rigid (‘tonic’); brief muscle twitching (‘myoclonus’); or the body flexing and extending repeatedly (‘epileptic spasms’).5,6


  • Non-motor symptoms – staring spells (‘absence’); changes in sensation, emotions, thinking or cognition; stomach/bowel sensations, waves of heat or cold, goosebumps, heart racing, etc.(‘autonomic functions’); or lack of movement (‘behaviour arrest’).5,6

Symptoms of Lennox–Gastaut syndrome

There are three key features that distinguish Lennox–Gastaut syndrome from other types of epilepsy:1,7


1. Multiple types of seizure.1,7 ‘Tonic’ seizures are the most common type, in which muscles contract and the body (or a part of it) becomes suddenly stiff. This can last from a few seconds to minutes, and typically occurs during sleep. ‘Atypical absence’ seizures are the second most common type, in which the person briefly loses consciousness, although some awareness may be preserved.7 ‘Drop attacks’ (sudden tonic or atonic falls) are a particularly hazardous type of seizure, characterised by abrupt falls which can result in injury. Drop attacks, which occur in at least 50% of people with Lennox–Gastaut syndrome, may necessitate the wearing of a helmet and face mask to prevent head injuries.7


2. Cognitive impairment.1,7 Many children with Lennox–Gastaut syndrome develop learning difficulties. These may sometimes be apparent before the onset of epilepsy, can worsen with time, and are often accompanied by behavioural problems ranging from hyperactivity to autistic behaviours.1


3. Abnormal electroencephalogram (EEG) features.1,7 An EEG is a non-invasive test that records brain activity by measuring electrical signals given off by brain cells.1 Abnormal EEG features can help to diagnose epilepsy in general, and people with Lennox–Gastaut syndrome have a distinctive pattern of electrical waves during (and sometimes between) seizures.

3-5 years

Is the age of onset that Lennox-Gastaut syndrome typically emerges.1

1-2 million

People worldwide are estimated to suffer with Lennox-Gastaut syndrome.8

Epidemiology and burden

Worldwide, approximately 27 million people suffer from epilepsy.9 Lennox–Gastaut syndrome is estimated to affect 1-2 million people and is thought to represent less than 5% of cases of childhood epilepsy.8


Lennox–Gastaut syndrome most commonly emerges between the ages of 3 and 5 years and is more common in boys than in girls.1 Lennox–Gastaut syndrome has different causes including brain damage resulting from, e.g., oxygen deprivation at birth, an infection, or a head injury. In up to around a third of cases of Lennox–Gastaut syndrome, no cause can be found.1


Lennox–Gastaut syndrome has a negative effect on intellectual development, the ability to interact with others and to function at school, and in some cases affects the ability to live independently. The majority of children will continue to have seizures into adulthood. Parents, family members and caregivers can struggle to cope, and many people with Lennox–Gastaut syndrome will need ongoing support with their condition.8

Diagnosis and care

Lennox–Gastaut syndrome is diagnosed based on Electroencephalograms (EEGs) that take place while awake and asleep, medical history, physical examination, and brain imaging.1 It can be difficult to differentiate Lennox–Gastaut syndrome from other types of epilepsy, and the specific pattern of electrical waves on EEGs can be helpful to pin down the precise syndrome.1


Lennox–Gastaut syndrome is one of the most complex epileptic disorders to manage. There is no cure, and the main objective of treatment is to gain seizure control whilst managing potential side effects such as fatigue or nausea.1 Although complete seizure control is not always achievable, and many patients will require lifelong management and support with daily living, a small percentage of affected adults are able to live independently.1,8


1. Young Epilepsy: Lennox-Gastaut syndrome information guide. PDF available at https://www.youngepilepsy.org.uk/dmdocuments/Lennox-Gastaut.pdf [Accessed March 2022]
2. Epilepsy overview: NHS Guide. https://www.nhs.uk/conditions/epilepsy/ [Accessed March 2022]
3. World Health Organisation. Epilepsy key facts. 2019. Available from: https://www.who.int/news-room/fact-sheets/detail/epilepsy [Accessed March 2022].
4. Young Epilepsy: Epilepsy Syndromes. https://www.youngepilepsy.org.uk/about-epilepsy/living-with-epilepsy/epilepsy-syndromes.html?jjj=1586421670048 [Accessed March 2022]
5. Epilepsy Society Seizure Classification https://epilepsysociety.org.uk/blog/ilae-new-seizure-classification-what-are-new-seizure-names [Accessed March 2022]
6. Epilepsy Foundation. Types of seizures. 2017. Available from: https://www.epilepsy.com/learn/types-seizures [Accessed March 2022].
7. Camfield PR. Definition and natural history of Lennox–Gastaut syndrome. Epilepsia. 2011;52(Suppl 5):3–9.
8. Medline Plus Lennox-Gastaut syndrome Overview. https://medlineplus.gov/genetics/condition/lennox-gastaut-syndrome/ [Accessed March 2022]
9. Global Burden of Disease Study 2017. Lancet 2018;392:1789-1858

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