A 3-year-old previously normally developing boy presents to the pediatric neurology clinic with a 2-month history of sudden falls during play. His parents describe brief jerking movements of the shoulders and arms immediately followed by loss of muscle tone, causing him to collapse forward onto the floor. He has sustained two facial lacerations from these falls. EEG shows the pattern marked **A** in the diagram. Which of the following best describes the ictal electromyographic (EMG) correlate of this seizure type?

Question

Accepted Answer

D. Polyspike component aligns with myoclonic jerk; slow wave aligns with silent period on EMG corresponding to atonic collapse. ## Why option 1 is right

The pattern marked **A** represents the EEG signature of Doose syndrome (myoclonic-atonic epilepsy). The defining seizure is the myoclonic-atonic drop: a brief symmetric myoclonic jerk immediately followed by sudden loss of postural tone. The ictal EEG correlate is a generalized polyspike-wave complex where the polyspike component precisely aligns with the myoclonic jerk of the shoulders/arms, and the slow wave aligns with the silent period on EMG that corresponds to the atonic collapse causing the forward fall. This dissociation between the myoclonic (polyspike) and atonic (slow wave/EMG silence) components is pathognomonic for Doose syndrome and distinguishes it from other generalized epilepsies of childhood. (Nelson Textbook of Pediatrics 21e; ILAE EMAS classification)

## Why each distractor is wrong

- **Option 2**: This describes hypsarrhythmia, the chaotic high-voltage multifocal spike pattern seen in West syndrome (infantile spasms), NOT Doose syndrome. The anchor explicitly states Doose does NOT show hypsarrhythmia.
- **Option 3**: This describes the 1.5-2.5 Hz slow spike-wave with paroxysmal fast activity during sleep characteristic of Lennox-Gastaut syndrome, NOT Doose. The anchor explicitly distinguishes Doose from Lennox-Gastaut by the absence of this pattern.
- **Option 4**: This describes a pure absence seizure with behavioral arrest and sustained muscle contraction, not the myoclonic-atonic drop. Doose may have absences with myoclonic components, but the defining seizure is the myoclonic-atonic drop with forward falls and facial injuries.

**High-Yield:** Doose syndrome = myoclonic-atonic drops (forward falls + facial injuries) + 2-3 Hz polyspike-wave on normal background + avoid sodium channel blockers + ketogenic diet highly effective.

[cite: Nelson Textbook of Pediatrics 21e; ILAE EMAS classification]

Answer

A. Slow spike-wave at 1.5-2.5 Hz with paroxysmal fast activity during sleep

Answer

B. Continuous high-voltage chaotic activity with multifocal spikes throughout the seizure

Answer

C. 3 Hz generalized spike-wave with sustained muscle contraction and behavioral arrest only

Explanation

Why option 1 is right

Why each distractor is wrong

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