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Myoclonic epilepsy in infancy

This is a very rare epilepsy syndrome. It is more common in boys than girls. Seizures begin from 4 months to 3 years of age, but most commonly between 1 and 2 years of age. Approximately a third of children with this condition have a family member who has epilepsy, or has had febrile convulsions as a young child. In most cases no cause is found for this type of epilepsy.

Epilepsy Action has more information on febrile convulsions.


Children have myoclonic seizures, which may be subtle and not noticed at first. They are brief, often involve head nodding, and usually happen several times a day. They may cause the child to lose their balance, but only rarely will the child fall. As the child’s head drops forward onto their body, their arms tend to jerk upwards and outwards, while their legs may flex. They sometimes roll their eyeballs upwards. It is very rare for children to have a tonic-clonic seizure.


The electroencephalogram (EEG) test, which records the electrical activity in the brain, shows evidence of abnormal discharges of spikes and waves, or polyspikes and waves, particularly as the child is falling asleep. The abnormalities can sometimes be made worse by exposure to flashing lights (photosensitivity).


The seizures nearly always respond to the epilepsy medicines sodium valproate (Epilim) or clonazepam (Rivotril). Levetiracetam (Keppra) might also be effective.

There may be research studies open that are relevant to this epilepsy syndrome. Your child’s doctor will be able to discuss this with you.

Information about treatments for children can be found on the Medicines for Children website.


Most children will stop having seizures by 5 or 6 years of age, sometimes sooner. Approximately half of children with benign myoclonic epilepsy in infancy have no problems with their behaviour or development. However, for some children, there is some risk of delayed learning, and in particular there may be delayed language development. These children may also have behavioural problems. It is not possible to predict at diagnosis which children will have these problems.


Freephone helpline (UK only): 0808 808 3555
Website: cafamily.org.uk
Email: info@cafamily.org.uk

What is a syndrome?

A syndrome is a group of signs and symptoms that, added together, suggest a particular medical condition. In epilepsy, examples of these signs and symptoms would be things like the age at which seizures begin, the type of seizures, whether the child is male or female and whether they have physical or learning disabilities, or both. The results of an EEG are also used to help identify epilepsy syndromes.

If you would like to know more about an epilepsy syndrome, please speak to your doctor. If you would like to know more about epilepsy in general, please contact Epilepsy Action.


Epilepsy Action would like to thank Drs Richard Appleton and Rachel Kneen (at Alder Hey Children’s Hospital, Liverpool) and Stewart Macleod (at Yorkhill Children’s Hospital, Glasgow), consultants who specialise in children’s epilepsy, who have updated this fact sheet.


This information is exempt under the terms of The Information Standard.

  • Updated February 2016
    To be reviewed February 2019

Comments: read the 2 comments or add yours


Hi!my little boy had an anti epileptic medicines now topamax(topiramate) and fycompa(perampanel) tablets and also valproic acid(depakene).for now his seizures reduced not just like before.wer praying that it will stop as soon as possible! By the way,may i ask about the difference between benign myoclonic epilepsy in infancy and west syndrome?are they the same?i hope that you can help me to clarify about these to two things because this time im confused.THANK YOU!

Submitted by ERN on


It sounds like things are difficult for your little boy. And he is on a lot of epilepsy medicine.

It can be difficult to diagnose very young children. Have a look at our information on epilepsy in babies for more information on this. Sometimes it can take doctors a few years to be sure of a diagnosis.

I notice you have looked at our benign myoclonic epilepsy in infancy information. This is

our information about West syndrome.

The symptoms, diagnosis and possible treatments are different in the 2 syndromes.

I hope this is helpful.



Epilepsy Action Helpline Team

Submitted by rich on

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