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.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.^1,2 Due to the severity of the seizures, as well as frequent injuries, developmental delays and behavioral problems, Lennox–Gastaut syndrome has serious health implications.²

A seizure is classified as either ‘generalized’ or ‘focal’, depending on whether it affects the whole brain or just a part of the brain.^5,6 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’).

• 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 (‘behavior arrest’).

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

• Multiple types of seizure.^1,7,8 ‘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. ‘Drop attacks’ are a particularly hazardous type of seizure, characterized by abrupt falls which can result in injury. Drop attacks, which occur in more than 50% of people with Lennox–Gastaut syndrome, may necessitate the wearing of a helmet and face mask to prevent head injuries.

• Cognitive impairment.^1,7 The majority of children with Lennox–Gastaut syndrome (80–90%) have learning difficulties. These may be apparent even before the onset of epilepsy, can worsen with time, and are often accompanied by behavioral problems such as hyperactivity, aggression, and autistic behaviors.

• Abnormal electroencephalogram (EEG) features.^1,7 An EEG is a device that attaches to the scalp and measures the electrical activity of the brain. 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.

Worldwide, 27 million people suffer from epilepsy.⁹ The ratio of adults with epilepsy to children with epilepsy is around 6:1.¹⁰ Lennox–Gastaut syndrome is thought to represent around 4% of cases of childhood epilepsy, though estimates vary.^8,11

Lennox–Gastaut syndrome most commonly emerges between the ages of 3 and 5 years, and almost always before the age of 8 years.¹ It is around 50% more common in boys than in girls.² There are many different causes of Lennox–Gastaut syndrome, of which the most common is brain damage resulting from, e.g., oxygen deprivation at birth, an infection, or a head injury.² In around a quarter to a third of cases of Lennox–Gastaut syndrome, no cause can be found, and genetics may play a role.²

Lennox–Gastaut syndrome is dangerous: 5% of those with the condition will die during childhood/adolescence – a 14-times greater risk of death than in children without the condition.^12,13 Lennox–Gastaut syndrome has a negative effect on intellectual development, the ability to interact with others and to function at school, and the ability to live independently.⁸ The majority of people with the disorder (80–90%) will continue to have seizures into adulthood.¹² Parents, family members and caregivers can struggle to cope, and many people with Lennox–Gastaut syndrome will ultimately be placed in an institution.^8,12

Lennox–Gastaut syndrome is diagnosed based on EEGs (while awake and asleep), medical history, physical examination, and magnetic resonance imaging (MRI) scans of the head.^2,7 It can be difficult to differentiate Lennox–Gastaut syndrome from other types of epilepsy, and the specific pattern of electrical waves on EEG can be helpful to pin down the precise syndrome.⁷

Lennox–Gastaut syndrome is one of the most complex epileptic disorders to manage.¹ There is no cure, and the main objective of treatment is to reduce the frequency of the most troublesome and dangerous seizures.² Although complete seizure control is not always achievable and patients will require lifelong management, medications are becoming available that can help to manage seizures in Lennox–Gastaut syndrome.^2,14