Benign Myoclonic Epilepsy in Infancy

Background

• One of the idiopathic generalized epilepsies
• 1% to 2% of epilepsies that start before the age of 3 years
• Seizures start between 0.5 and 3 years of age in developmentally normal children. However, some cases have a later onset up to 4 years
• A family history of febrile seizures and epilepsy is often reported
• Remission usually occurs within 1 year (6 months to 5 years) from onset.
• The outcome is generally benign. In rare cases, myoclonic epilepsy such as Juvenile Myoclonic Epilepsy may follow Benign Myoclonic Epilepsy in Infancy

Clinic

• Myoclonic jerks involving mostly the upper part of the body, singular or clusters
• Consciousness is normally intact
• Photosensitivity in 20% of the patients
• Unexpected acoustic or tactile stimuli can elicit a the myoclonic jerks in 10%.
• During sleep in most of the patients the myoclonic seizures persists

Treatment

• Valproic acid was effective in 23 of 30 treated patients
• Patients with acoustic and somatosensory evoked myoclonic seizures may not need treatment.

EEG

• Inter-ictal: Usually normal, sometimes generalized Spike slow wave complex or Polyspikes slow wave complex
• Ictal: Brief generalized Spike slow wave complex or Polyspikes slow wave complex
• Sometimes photosensitivity
• Normal background rhythm
• Electromyogram show one or repetitive myoclonia

---

5 year old girl with 3 Hz generelized polyspike waves and myoclonic jerks (double banana and EMG on deltoid muscle)

---

Notes