Early myoclonic encephalopathy

28th February 2019

This particular syndrome will usually begin very early in the newborn period, normally before 2 to 3 months of age. The underlying cause of early myoclonic encephalopathy is often a metabolic disorder known as nonketotic hyperglycinemia, however, it can also be caused by brain malformations and neurogenetic disorders.  


Seizures can vary with this syndrome. They are often subtle myoclonic seizures that affect small areas of the body and may not be noticeable straight away. However, they can also be more severe myoclonic or focal (partial) seizures. It’s more rare for a tonic clonic seizure, but it does happen. Read our guide to the different types of seizures for more information on each of these.

Seizures will be frequent throughout the day, over time they may become infantile spasms, also known as west syndrome.


An electroencephalogram (EEG) test is the best method for diagnosing early myoclonic encephalopathy. An EEG records electrical activity within the brain, which is a non invasive procedure. There’s a particular pattern, known as a ‘suppression burst’ pattern, that may indicate early myoclonic encephalopathy, which is abnormal discharges or spikes and waves that are mixed with periods of flatness. Children with this syndrome are also usually excessively sleepy and quite ‘floppy’ by nature, which may give a healthcare professional additional reason to suspect early myoclonic encephalopathy.


Treatment for this particular syndrome can be difficult due to the number of causes. Firstly, the baby should be tested for a metabolic disorder as it may be possible to treat this rather than the epilepsy. There are a number of medications that may be trialled to find the most suitable option, however, it can be a difficult process finding the right one as these seizures are often resistant to epilepsy medications. The usual choices may include zonisamide or levetiracetam.   


Infants who are born with early myoclonic encephalopathy will sadly make very little developmental progress and more than 50% will not survive past their first year. Most babies will feed poorly, which leads to them requiring feeding via a PEG (gastronomy tube) inserted directly into the stomach. Those who do survive will likely require constant care and experience severe developmental issues as a result of the syndrome.

National Epilepsy Training can help

For more information and advice on early myoclonic encephalopathy, please call us on 01706 373075 or email admin@nationalepilepsytraining.co.uk.