An epileptic encephalopathy is a disorder in which the spike and sharp wave (epileptiform) activity on the EEG impairs brain function. This typically occurs when the epileptiform activity occur during sleep. This activity may respond to anti-seizure medications. Certain seizures and epilepsy syndromes commonly cause an epileptic encephalopathy.
Seizures and epilepsy may be associated with cognitive and behavioral problems. The degree of impairment is related to seizure frequency, seizure type, cause of seizures, anti-seizure medications, and the abundance of EEG epileptiform activity, especially during sleep. In an epileptic encephalopathy, the epileptic activity itself contributes to cognitive and behavioral problems; beyond what is expected from the underlying cause. An epileptic encephalopathy can cause progressive academic, behavioral, and even motor problems.
An epileptic encephalopathy may exist without an actual clinical seizure. The EEG is critical to evaluate a child for an epileptic encephalopathy: to identify the epileptiform activity and quantify its abundance, especially during sleep. The hallmark EEG finding is electrical status epilepticus of sleep (ESES). The more sleep-activated the EEG, the more likely an associated cognitive or behavioral problem. The severity is determined by scoring the spike-wave index, done only by very specialized epilepsy centers.
Management requires treatment of the actual clinical seizures with attention placed on the abundance of EEG epileptiform activity. Classical seizure treatment mandates that “we treat the patient, not the EEG.” But in an epileptic encephalopathy, the problem extends beyond the clinical seizures, which may be easy to control, and must focus on reducing epileptiform activity: the doctor must also treat the epileptic EEG activity. This can be determined with prolonged EEG monitoring. Neuropsychological evaluation is critical to assess regression and improvement with therapy.
An epileptic encephalopathy frequently involves children but may occur in adults.
There are specific conditions included as epileptic encephalopathies:
Benign Epilepsy Variants: An epileptic encephalopathy may also occur in the benign childhood epilepsies, especially Benign Rolandic epilepsy; referred to as “atypical Rolandic epilepsy, benign Rolandic epilepsy variants, malignant Rolandic epilepsy, or borderland syndromes.” The benign occipital epilepsies may also be associated with an epileptic encephalopathy.
An epileptic encephalopathy must be considered in any person with epilepsy who develops a loss of abilities, even when the actual seizures are under control.
The major clinical problems (co-morbid disorders) with an epileptic encephalopathy:
Treatment of an epileptic encephalopathy starts with a neurologic evaluation to identify the underlying cause. Most epileptic encephalopathies occur in people with known epilepsies. However, infectious, metabolic, or autoimmune disorders may be responsible.
The seizure treatment starts with a standard anti-seizure medication that suppress spikes (the anti-epileptic effect) in addition to controlling seizures (the anti-convulsant effect). Treatment is assessed by control of seizures and improvement in cognitive function which usually follows EEG improvement. Behavioral problems may not always improve along with EEG improvement and may require specific psychopharmacologic treatment.
The epileptic encephalopathies may require combination treatment of the standard anti-seizure medications along with high dose benzodiazepines, corticosteroids, or intravenous gammaglobulin (IVIG).
Successful treatment requires the teamwork of various specialists, including an epileptologist, psychopharmacologist, neuropsychiatrist, neuropsychologist, nurse practitioner, and dietician.
Research is an important part of the treatment of the epileptic encephalopathies, since these patients may not respond to standard anti-seizure medications. We are studying the effects of high dose benzodiazepines and pulse intravenous corticosteroids on the EEG, the neuropsychologic manifestations of electrical status epilepticus of sleep, and the genetics of the epileptic encephalopathies.
The Center for Epileptic Encephalopathies (CEE) in the Comprehensive Epilepsy Center at NYU/Langone Medical Center: