Rare Epilepsy Syndromes
Progressive Myoclonic Epilepsy: A rare form of epilepsy with myoclonic (jerking) and tonic-clonic (grand mal) seizures. Children with this condition may have trouble with maintaining balance and experience rigid muscles. There is also a loss of mental ability. A gene for this disorder has recently been discovered.
Rasmussen's Syndrome: Also known as Rasmussen's encephalitis, begins in childhood and produces a slow deterioration of one whole side (hemisphere) of the brain with loss of function on the opposite side of the body. An autoimmune response to a viral infection has been suggested as a possible cause. Various types of treatment have been tried, including surgical removal of the affected side of the brain. In children, the remaining hemisphere may compensate for functions lost, but weakness on the affected side will remain.
The condition typically starts with seizures, with weakness appearing later in the course of the disorder. Simple partial seizures affecting movement are the most common form.
- Begins between 3 to 7 years old
- Progressive loss of speech
- Seizures during sleep
- Loss of IQ
Landau-Kleffner syndrome, a rare disorder, causes children to develop the inability to speak. They have trouble understanding speech and may seem not to hear or understand what is said to them. Many children will also have seizures; these seizures vary in type. Speech in children with the syndrome slowly declines over time. There are epilepsy-related abnormalities on the EEG, even though some of the children do not have seizures.
The syndrome typically begins in children between 3 to 7 years old. Understanding spoken language is usually affected, but the children may also lose the ability to speak as well. Seizures often occur while the child is asleep and may be quite infrequent. Simple partial and tonic-clonic seizures may occur. Treatment with standard anti-epileptic drugs is not very effective; treatment with steroids has been tried with some success. Multiple subpial transection, a form of surgery designed to spare the speech areas, has also been tried.
Language for many of these children will improve slowly over time, but may not return to a normal level for age. EEGs may continue to be abnormal, even when the speech has improved.