What is Lennox-Gastaut syndrome (LGS)?

Lennox-Gastaut syndrome, or LGS, is a type of epilepsy, which is when people have seizures. Seizures occur when there is a sudden abnormal burst of electrical activity in the brain that interferes with normal brain activity. People with LGS can have different types of seizures. These include atonic seizures, or drop attacks, when their muscles suddenly shut down and they might fall to the ground. There may have tonic seizures, which are when the muscles suddenly go totally stiff. With these, people can fall down too, and crash to the ground. During an absence seizure, people can’t respond to what is going on around them. Different types of seizures may happen several times a day, but the type and frequency of seizures varies from one individual to the next.

In addition to having seizures, people with LGS find it harder to learn, to understand things, and to manage everyday needs.They may behave differently, and sometimes get more upset and irritable.

Lennox-Gastaut syndrome is a severe form of epilepsy. Seizures usually begin before four years of age. Seizure types, which vary among patients, include tonic (stiffening of the body, upward deviation of the eyes, dilation of the pupils and altered respiratory patterns), atonic (brief loss of muscle tone and consciousness causing abrupt falls), atypical absence (staring spells) and myoclonic (sudden muscle jerks). There may be periods of frequent seizures mixed with brief, relatively seizure-free periods. Most children with Lennox-Gastaut syndrome experience some degree of impaired intellectual functioning or information processing, developmental delays and behavioral disturbances. Lennox-Gastaut syndrome can be caused by brain malformations, perinatal asphyxia, severe head injury, central nervous system infection and inherited degenerative or metabolic conditions. In 30 to 35 percent of cases, no cause can be found.

This answer is based on source information from the National Institute of Neurological Disorders and Stroke .

Lennox–Gastaut syndrome is a childhood-onset epilepsy that most often appears in children between 2 and 6 years old. Lennox-Gastaut is characterized by a triad of signs including frequent seizures of multiple types, an abnormal electroencephalogram (EEG) pattern and moderate to severe intellectual impairment.

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