From infancy into adulthood, there are a number of classic EEG patterns and syndromes that are important to recognize. These patterns have distinct treatment requirements and prognoses. Below is an overview of some common syndromes and their EEG signatures.

1. Ohtahara Syndrome (EIEE)

Ohtahara syndrome, now referred to as early infantile epileptic encephalopathy (EIEE), is a severe condition seen in early infancy.

  • EEG Pattern: Characterized by burst suppression with high-amplitude, multifocal spikes embedded within bursts of activity.
  • Clinical Features: Multiple seizure types, most commonly tonic seizures or spasms, along with significant intellectual disability and developmental delay.
  • Prognosis: EIEE often leads to early death but may progress into West Syndrome or Lennox Gastaut Syndrome.

2. Hypsarrhythmia & Infantile Spasms

Hypsarrhythmia is a highly concerning EEG pattern seen in infants, typically in the setting of infantile spasms (West Syndrome).

  • EEG Pattern: A high-amplitude, disorganized, slow background with multifocal epileptiform discharges.
  • Clinical Features: Triad of hypsarrhythmia on EEG, epileptic spasms, and developmental delay/regression.
  • Treatment: Urgent treatment is critical to prevent long-term developmental sequelae and intractable seizures.

Hypsarrhythmia Examples

  • Hypsarrhythmia at 7uV/mm
  • Hypsarrhythmia at 50uV/mm

3. Lennox Gastaut Syndrome (LGS)

Lennox Gastaut Syndrome (LGS) can evolve from EIEE or West Syndrome, or arise independently. It is a severe form of epileptic encephalopathy.

  • EEG Pattern: Diffuse, prominent slowing with 2.5-3 Hz generalized spike-wave discharges.
  • Clinical Features: Multiple seizure types and intellectual impairment.

4. Benign Epilepsy with Centrotemporal Spikes (BECTS)

Benign epilepsy with centrotemporal spikes (BECTS) is a common, self-limiting disorder in children, often resolving by adolescence.

  • EEG Pattern: Centrotemporal spikes, which can be unilateral or bilateral.
  • Clinical Features: Focal nocturnal seizures with unilateral facial spasms that can progress to involve the ipsilateral arm and leg.
  • Age of Onset: Typically occurs between 1-4 years of age.

5. Absence Epilepsy

Absence seizures are characterized by brief, generalized spike and slow wave discharges and are typically seen in absence epilepsy.

  • EEG Pattern: 2.5 Hz generalized spike and slow wave pattern.
  • Clinical Features: Seizures are brief, with rapid onset and offset, and no postictal state.
  • Treatment: First-line treatment with ethosuximide.

6. Electrical Status Epilepticus of Sleep (ESES)

Electrical status epilepticus of sleep (ESES), also known as continuous spike and waves during slow-wave sleep (CSWS), involves a dramatic increase in interictal activity during sleep.

  • EEG Pattern: Spikes present in more than 85% of non-REM sleep, with hemispheric predominance during sleep.
  • Associated Condition: Commonly found in Landau Kleffner Syndrome, where children experience seizures and language regression due to nightly ESES.

ESES Examples

  • Awake: Occasional left hemispheric predominant discharges.
  • Asleep: Continuous spike and waves during sleep.

7. Juvenile Myoclonic Epilepsy (JME)

Juvenile myoclonic epilepsy (JME) is a common pediatric epilepsy syndrome that typically arises in adolescence and can persist into adulthood.

  • EEG Pattern: Intermittent 4-6 Hz generalized spike or polyspike and slow-wave pattern.
  • Clinical Features: Characterized by myoclonic jerks, particularly in the morning.

Summary

Pediatric syndromic EEG patterns vary widely, from the severe and progressive conditions like Ohtahara Syndrome and Lennox Gastaut Syndrome, to the more benign conditions like Benign Epilepsy with Centrotemporal Spikes. Recognizing these characteristic EEG patterns is crucial for accurate diagnosis, timely treatment, and understanding the prognosis for each syndrome.