As with most medical disorders, the spectrum of severity seen in MAE ranges from mild to those more severely affected. Children mildly affected by MAE may have their seizures quickly and easily controlled with first-line medications, alone or in combinations. Those children on the more severe end of the MAE spectrum may have difficulty finding an effective medication or treatment. As more is learned about MAE and new treatment options emerge, the outcomes continue to improve.
Myoclonic-Astatic Epilepsy usually occurs in children with an uneventful history; there is likely to be no pre-existing neurological disorder.
It clearly affects more boys than girls at a ratio of about 3:1.
In 24% of the cases, the epilepsy starts during the first year of life (at 2, 4 or 5 months of age).
In 94% of the cases, the epilepsy starts within the first five years of life.
In 100% of cases, the child develops myoclonic and/or myoclonic-astatic (or drop) seizures. The -astatic (loss of muscle tone) feature of the myoclonic-astatic seizure is rare and unique to MAE, and is the most important and distinct feature which helps differentiate it from other syndromes.
In addition to myoclonic seizures, children may also have a combination other generalised seizures including tonic-clonic, absence and non-convulsive status epilepticus and, rarely, tonic seizures. See Seizure types.
Hallmark features on an EEG help define MAE and, in almost all cases, rhythmic parietally accentuated 4-7 Hz background seizure activity develops early in the course
MAE belongs to a large group of idiopathic generalised epilepsies referred to as GEFS+ (Generalised Epilepsies with Febrile Seizures Plus). Disorders associated with GEFS+ are inherited or genetic so there may be, but not always, a family history of seizures. Most epilepsies in this group are usually outgrown in childhood, relatively benign or easy to treat. Within the GEFS+ spectrum, more severe and complex syndromes can occur including MAE and Dravet's Syndrome (SMEI or Severe Myoclonic Epilepsy of Infancy).
Some of the epilepsy types associated within the wide GEFS+ spectrum include:
Febrile seizures (FS) where seizures with fever or high temperature occur. FS affect 3% of ALL children, commonly outgrown by the age of 6 with low risk of epilepsy in later life.
Febrile seizures plus (FS+) where febrile seizures continue beyond 6 years of age sometimes interspersed with afebrile seizures occur.
FS+ and absence seizures
FS+ and myoclonic seizures
FS+ and partial seizures
Myoclonic-astatic epilepsy (MAE or Doose Syndrome)
Dravet's Syndrome (SMEI or Severe Myoclonic Epilepsy in Infancy)
Several genes responsible for epilepsy in the GEFS+ group have already been identified. At present, this is largely research except in the case of SMEI (Dravet's Syndrome) where a diagnostic test to identify the gene SCN1A has been developed which can help confirm clinical findings and lead to better management of the disorder.
The genetics of MAE are still not fully understood. We know that it is polygenic meaning more than one gene is responsible for the disorder but we don't know how many genes. It is likely that mutations (or defects) of several genes have a combined effect to result in MAE. It is expected that in years to come, the genes responsible for MAE will be identified and this will help confirm a diagnosis, target medications and treatments leading to better management and improved outcomes for our children. One day it may even possible to switch off these faulty genes.
Various studies over recent years have shown that the ketogenic diet is extremely effective in controlling seizures in children with MAE, and is now considered one of the most successful treatments for the disorder, even more successful, according to some centres, than the more traditional anti-epileptic drugs. Parents who achieved seizure control through AEDs but with bothersome or inhibitory cognitive side effects have also chosen this form of therapy as an alternative to medication. Some children require a combination of the ketogenic diet as well as medication added, others respond completely to the diet alone.
(Findings on the effectiveness of the ketogenic diet in treating MAE were reported in 2005. Dr Laux and associates, from Northwestern University, Chicago, Illinois, retrospectively analysed the records of 10 children with MAE who received the ketogenic diet. Of these 10 children, 7 either became seizure-free or experienced a greater than 90% seizure reduction, and the remaining 3 children had a greater than 50% seizure reduction. This study showed that patients with MAE are highly responsive to the effects of the ketogenic diet.)
Steroids have also been successfully used as treatment for MAE in some children, either with or without accompanying AEDs. Most widely used is a steroid known as ACTH, an injected steroid previously more commonly used as a treatment for another childhood seizure disorder, Infantile Spasms (West Syndrome). Oral prednisone/prednisolone has also shown tremendous success in seizure control, either as a therapy on it's own, or as a maintenance/weaning agent following a course of ACTH.
There are cases where, regardless of treatment and the state of current seizure control, the child will - either gradually or suddenly - cease having seizures. These children are presumed to be amongst those who have gone into spontaneous remission.
MAE is a syndrome with variable courses and various outcomes, meaning that the treatment each individual child responds to will also be highly variable. There is no 'right' answer that encompasses the whole range of children - each parent in conjunction with their treating physician must therefore be part of the process where they strive for the ideal treatment for their individual child to be found. Reading the experiences of families who have found what's worked for them with seizure control may aid in this process, as hopefully will reading about cases where treatments known to have the potential to aggravate MAE seizures or induce paradoxical seizures have been involved.