Ictal Recordings
- Epileptiform discharges averaging >2.5 Hz for ≥10 s (>25 discharges in 10 s)
- Any pattern with definite evolution lasting ≥10 s
- Definite clinical correlate time-locked to pattern
- EEG + clinical improvement with IV anti-seizure medication
- ≥10 continuous minutes, OR
- ≥20% of any 60-minute recording
- ≥10 continuous minutes, OR
- ≥20% of 60 minutes, OR
- ≥5 minutes if convulsive
Possible ECSE:
RPP ≥10 min or ≥20% of recording with EEG improvement but no clinical improvement
- Rhythmic activity >4 Hz lasting 0.5–10 s
- Not normal/benign variant
- No definite clinical correlate
- Evolution, OR
- Matches morphology/location of known epileptiform discharges
- Sharply contoured only
- PD/SW >1 Hz but <2.5 Hz
- PD/SW 0.5–1 Hz WITH modifiers
- Lateralized RDA >1 Hz
Does NOT qualify as ESz or ESE
Ictal Recordings - EMU[edit | edit source]
It is rare to capture a seizure during a routine EEG, because the study is a random sampling of someone who has paroxysmal events. For this is the reason, we tend to admit these patients to the hospital and reduce their medications in order to increase the chance of recording a typical event while they undergo prolonged monitoring with video and EEG to optimize the amount of information we can get about the seizures. Ictal patterns can vary widely. The rule of thumb is that a rhythmic pattern that varies in frequency, amplitude, and location is most likely a seizure. The onset of a seizure provides the most localizing information because it is most likely to represent the ictal onset zone. Any other focal pattern later in the seizure may simply represent a spread pattern. At the conclusion of an ideal neurophysiological evaluation the epileptogenic zone, symptomatogenic zone and the ictal onset zone should all overlap before we would consider them for a surgical resection.