EEG | Interictal: - Hypsarhythmia, multifocal or focal epileptiform discharges (that might be seen quickly after the spasms onset)
| Interictal: - Normal EEG
- Suppression-burst pattern
| Ictal: - Normal EEG during recorded clinical events of suspected spasms
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Comorbidities | Developmental slowing after spasms onset but may be absent early in the course (difficult to determine in a child with existing significant developmental disorders) | | |
Possible evolving syndrome: Infants with preceding brain injury, developmental brain malformations, or specific genetic conditions, including early-infantile DEE, who show significant interictal EEG abnormalities (high amplitude, background slowing, and/or multifocal discharges) should be watched carefully for the development of clinical epileptic spasms. However, the syndrome of IESS cannot be diagnosed prior to onset of the mandatory seizure type. |
Syndrome without laboratory confirmation: In resource-limited regions, an interictal EEG is highly recommended. However, if EEG is unavailable, if clear clusters of typical epileptic spasms are witnessed by an experienced clinician (in person or on video recording), with the other clinical mandatory and exclusionary criteria, IESS can be diagnosed. |