EEG Pediatric and Neonatal EEG 5 — Questions and Answers
Question 1: Which neonatal seizure type is most commonly electrographic-only (without clinical correlate) and therefore detectable only by EEG?
- Clonic seizures
- Tonic seizures
- Subtle seizures
- Electrographic-only (subclinical) seizures (Correct answer)
Correct answer: Electrographic-only (subclinical) seizures
Subclinical (electrographic-only) seizures in neonates have no visible clinical manifestation and can only be detected through continuous EEG monitoring.
Question 2: The 'delta brush' pattern in neonatal EEG consists of what characteristic morphology?
- High-amplitude delta waves with superimposed fast activity (beta) (Correct answer)
- Triphasic waves with frontal predominance
- Generalized polyspike-wave complexes
- Alpha activity with intermittent theta bursts
Correct answer: High-amplitude delta waves with superimposed fast activity (beta)
Delta brushes are high-amplitude delta waves with superimposed fast (beta) activity, normally seen in premature neonates between 26–32 weeks gestational age.
Question 3: In childhood absence epilepsy, the typical ictal EEG discharge consists of:
- 2 Hz spike-and-wave
- 3 Hz spike-and-wave (Correct answer)
- Fast (>10 Hz) rhythmic activity
- Focal theta with phase reversal
Correct answer: 3 Hz spike-and-wave
Childhood absence epilepsy is characterized by generalized, symmetric 3 Hz (2.5–4 Hz) spike-and-wave complexes that are abrupt in onset and termination.
Question 4: What is the significance of a markedly asymmetric background in neonatal EEG?
- It is a normal variant in preterm neonates
- It suggests ipsilateral hemispheric injury or contralateral hemispheric dysfunction (Correct answer)
- It is diagnostic of neonatal epilepsy
- It indicates artifact from electrode placement
Correct answer: It suggests ipsilateral hemispheric injury or contralateral hemispheric dysfunction
Persistent interhemispheric amplitude asymmetry (>50%) in a neonate suggests structural injury on the side with attenuated activity or dysfunction on the opposite side.
Question 5: Which EEG feature helps distinguish benign childhood epilepsy with centrotemporal spikes (BECTS/BCECTS) from other focal epilepsies?
- Spikes that persist during all sleep stages
- High-amplitude centrotemporal spikes that increase during NREM sleep and have a characteristic horizontal dipole (Correct answer)
- Multifocal independent spikes
- Suppression of alpha rhythm over the affected hemisphere
Correct answer: High-amplitude centrotemporal spikes that increase during NREM sleep and have a characteristic horizontal dipole
BECTS is characterized by high-amplitude centrotemporal sharp waves with a horizontal dipole that markedly activate (increase in frequency) during NREM sleep.
Question 6: A preterm neonate at 28 weeks gestational age should demonstrate what characteristic EEG background pattern?
- Continuous high-amplitude activity similar to term infants
- Highly discontinuous pattern with long interburst intervals (up to 60 seconds) (Correct answer)
- Abundant K-complexes and sleep spindles
- Continuous theta-alpha activity with no discontinuity
Correct answer: Highly discontinuous pattern with long interburst intervals (up to 60 seconds)
At 28 weeks gestational age, the normal EEG is highly discontinuous with interburst intervals that can normally last up to 60 seconds, reflecting cerebral immaturity.
Question 7: In Lennox-Gastaut syndrome (LGS), which EEG pattern is characteristically seen during wakefulness?
- 3 Hz generalized spike-wave
- Slow (<2.5 Hz) generalized spike-and-wave complexes (Correct answer)
- Hypsarrhythmia
- Rolandic sharp waves
Correct answer: Slow (<2.5 Hz) generalized spike-and-wave complexes
LGS is characterized by slow (<2.5 Hz, typically 1.5–2.5 Hz) generalized spike-and-wave complexes during wakefulness, distinguishing it from childhood absence epilepsy.
EEG Pediatric and Neonatal EEG 5
Which neonatal seizure type is most commonly electrographic-only (without clinical correlate) and therefore detectable only by EEG?