Syndrome, Lennox-Gastaut: A severe form of epilepsy that usually begins in early childhood and is characterized by frequent seizures of multiple types, mental impairment, and a particular brain wave pattern (a slow spike-and-wave pattern). The seizures that are notoriously hard to treat and may lead to falls and injuries can be reduced in frequency by treatment with lamotrigine, a chemically novel antiepileptic drug. The syndrome is named for W.G. Lennox and H. Gastaut who described it.
The Lennox-Gastaut syndrome usually develops in children between 1 and 8 years of age and is characterized by seizures, developmental delay, and behavioral disturbances such as poor social skills and attention-seeking behavior. Most children with it have impaired intellectual functioning or information processing.
The disorder may be caused by brain injury, severe brain infections, genetic brain diseases, or developmental malformations of the brain. In some cases, no cause can be found.
The types of seizures, which vary among Lennox-Gastaut 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.
The prognosis (outlook) for individuals with Lennox-Gastaut syndrome varies. There is no cure for the disorder. Complete recovery including freedom from seizures and normal development is very unusual.