Lennox-Gastaut syndrome

Also known as: Lennox syndrome


Lennox-Gastaut syndrome is the name given to a group of severe epilepsies that occur in childhood. It sometimes follows the onset of seizures in the first year of life, which may include infantile spasms (see West syndrome) or happen separately.

The onset, which is usually under the age of five years, may be quite acute, with multiple seizures and loss of skills, or initially as infrequent seizures. Although originally described as having a characteristic electroencephalogram (EEG) pattern of slow-spike wave, the main clinical features of this condition are of a child developing several types of seizures with slowing or regression in their development.


Last updated October 2013 by Professor Brian Neville, Emeritus Professor of Paediatric Neurology, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK.

What are the symptoms?

The seizures include tonic (generalised stiffening) myoclonic (fast jerks), atypical absences (loss of responsiveness, which may not be complete), partial (stiffening and jerking of one body segment) and generalised (stiffening and jerking of the whole body) tonic−clonic attacks. Very commonly, the seizures also include episodes of non-convulsive status epilepticus, in which the child lapses into a groggy state and may have difficulty with communication (regression), feeding and walking. There are more children and young adults with multiple seizure types and regression than those who precisely fit the above EEG definition and, from the families’ point of view, it is reasonable to include many within the group.

Most children affected have learning difficulties which may vary both in extent and from time to time. A range of psychological problems, including attention deficit (see entry Attention Deficit Hyperactivity disorder and autistic features (see entry Autism Spectrum conditions) are common.

What are the causes?

Some are caused by a non-progressive dysplasia (defect of brain formation) which may be surgically treatable or is otherwise scan-negative and requires anti-convulsant treatment.

How is it diagnosed?

The diagnosis is made upon the evolution of the condition, its tendency to show regression and the EEG features.

How is it treated?

This condition is often resistant to drug treatment and may pose long-term problems with variable and unpredictable levels of functioning. There is a danger that polytherapy (a therapy that uses more than one type of drug) may cause more problems. A small number of children show a milder and self-limiting pattern. The condition may occur in a child with normal or slow early development. Occasionally, surgical treatment may be possible if there is a removable area of brain damage responsible for the seizures or if ‘drop attacks’ are the main seizure type, a corpus callosotomy, i.e. a partial or total division of the two halves of the cerebral hemispheres, may be required.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
None has been found.

Prenatal diagnosis

Is there support?

Lennox-Gastaut Support Group

Tel: 01664 454 305
Email: andrew.gibson15@btopenworld.com

The Group offers support and information and links families where possible. It is in contact with over 200 families and healthcare professionals.

Group details last updated December 2014.

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