Why Pediatric EEG is Different

Why Pediatric EEG Is Different

John Giang, MD

Why it matters

The pediatric EEG is a moving target: findings that are normal at one age are abnormal at another, and normal neonatal features (diffuse slowing, discontinuity, asynchrony, minimal reactivity) would be grossly abnormal in older children and in an adult. Without the patient’s exact age, the same EEG page cannot be called normal or abnormal.

Key points

• Maturation drives the tracing. Waking background moves from delta to theta to alpha; amplitude is higher than in adults. Pediatric normal awake in greater detail here.
• Neonates follow separate rules. States are quiet vs active sleep, emerging ~29 wk PMA. Discontinuity is normal if the interburst interval fits PMA (≤20 s at 28 wk, ≤10 s at 34–36 wk, ≤6 s at term); reactivity may be absent to 28 wk; synchrony completes by 38 wk. A reduced montage with EOG, chin EMG, respiration and ECG is used until ~46 wk PMA.
• Slower page speed. Neonatal records are read at 15 mm/s (20 s/page) rather than the adult 30 mm/s, so slow patterns and long interburst intervals can be judged. Older children return to 30 mm/s with the full 10–20 montage.
• Age is the first data point. Neonates: use PMA (gestational + chronological age). Children: age sets the expected PDR, background slowing and normal sleep features (asynchronous spindles to 6–12 mo, spiky vertex trains in infancy, hypnagogic hypersynchrony at 2–4 yr).

Common pitfalls

• Accepting a 3–4 Hz PDR at 12 months (delayed) or a PDR ≤8 Hz at 7 years (mild generalized slowing).
• Overcalling preterm discontinuity as burst-suppression because PMA was not checked.
• Reading a neonatal record at 30 mm/s.
• Mistaking sharp vertex waves or hypnagogic hypersynchrony for epileptiform discharges.
• Expecting eye-opening reactivity before 2–4 months or hyperventilation cooperation before ~3 years.