top of page
Background.jpg

EEG in Epilepsy: Ohtahara Syndrome (Early Infantile Epileptic Encephalopathy)

  • Roya Tompkins
  • 22 minutes ago
  • 2 min read

This week’s post continues our EEG in Epilepsy Series with a closer look at Ohtahara syndrome—also known as Early Infantile Epileptic Encephalopathy (EIEE). This rare but severe form of early-onset epilepsy is important for EEG technologists and neurologists to recognize, as early diagnosis can guide timely intervention and family counseling.


Let’s take a look at Ohtahara syndrome; otherwise known as Early Infant Epileptic Encephalopathy (EIEE).

Key Clinical Features


  • Seizures typically begin within the first 3 months of life, often appearing in the first 1–2 weeks.

  • Episodes are frequently difficult to control and may require multiple anti-seizure medications.

  • Infants often experience more than one seizure type, making Video EEG monitoring especially valuable in establishing an accurate diagnosis.

  • Tonic spasms are the most common and characteristic seizure type.

  • Due to the underlying neurological dysfunction, affected infants will show significant developmental delay and hypotonia (low muscle tone).


Common Causes of Ohtahara Syndrome


The most frequent cause of Ohtahara syndrome is a structural brain malformation. However, other contributing factors may include:

  • Metabolic disorders

  • Genetic abnormalities

  • Idiopathic origins when no clear cause is identified


EEG Findings: What to Expect



One of the hallmark features of Ohtahara syndrome is a distinctive interictal EEG pattern known as burst suppression.
One of the hallmark features of Ohtahara syndrome is a distinctive interictal EEG pattern known as burst suppression.

This pattern is characterized by:

  • High‑amplitude slow waves and polyspikes

  • Alternating periods of relative suppression with minimal electrical activity


The primary EEG pattern for Ohtahara Syndrome: Burst Suppression
The primary EEG pattern for Ohtahara Syndrome: Burst Suppression








The recognition of this pattern is essential, as it strongly supports the diagnosis and helps differentiate Ohtahara syndrome from other early‑onset epileptic encephalopathies.


Stay Connected

To receive weekly updates from our EEG in Epilepsy Series straight to your inbox - just click here to subscribe.


Explore More in This Series

Continue learning by reviewing our other posts on:

and much more by visiting the site.


Roya Tompkins, MS, REEG/EP T, RPSGT, CLTM


Resources:  

Child Neurology Foundation

Science Direct




Comments

bottom of page