Lennox syndrome: A severe form of epilepsy that is characterized by the onset in early childhood of frequent seizures of multiple types, developmental delay, a particular brain wave pattern (a slow spike-and-wave pattern), and behavioral disturbances with poor social skills and attention-seeking behavior. The types of seizures may 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). The seizures in this syndrome are notoriously hard to treat and may lead to falls and injuries. The seizures can be reduced in frequency by treatment with lamotrigine, a chemically novel antiepileptic drug. The prognosis (outlook) varies. There is no cure for the disorder. Complete recovery including freedom from seizures and normal development is very unusual.
Also known as the Lennox-Gastaut syndrome for W.G. Lennox and H. Gastaut who described it.