Utility of stereo‐electroencephalography in patients with bilateral independent/unclear scalp electroencephalographic seizure onset
Bibliographic record
Abstract
OBJECTIVE: This study was undertaken to determine whether bilateral independent or unclear (BI/U) scalp electroencephalographic (EEG) ictal onset patterns may predict the diagnostic yield of stereo-electroencephalography (SEEG) and inform surgical decision-making in patients with focal drug-resistant epilepsy. METHODS: We conducted a retrospective cohort study of consecutive patients with focal drug-resistant epilepsy and BI/U ictal onset on scalp EEG who underwent SEEG evaluation at our center between January 2012 and December 2024. All patients had undergone noninvasive and invasive presurgical assessments. Surgical outcomes were determined using the Engel classification following at least 1 year of postoperative follow-up. A blinded decision validation substudy was also performed, where the team made decisions regarding SEEG and surgical interventions when patients found to have a single SEEG seizure onset zone (SOZ) were presented. Responses were stratified to inform the added diagnostic value of SEEG. RESULTS: Of 255 SEEG cases screened, 84 patients (33%) had BI/U ictal onset on scalp EEG. The cohort was 56% female, with a median seizure onset age of 12 years (interquartile range = 6-20); 65.5% had temporal lobe epilepsy (TLE). A single SOZ was identified in 14.3% of cases (TLE: 14.5%, extratemporal: 13.8%). These patients had shorter SEEG recording durations (mean = 11 vs. 15.79 days in those with multifocal SEEG SOZs, p = .009). Curative focal resections were performed in 12% (n = 10), with long-term Engel I outcomes achieved in one patient of the entire cohort (1.2%). Palliative resections occurred in 26% (n = 22), with Engel I outcomes in 7% (n = 6). In 50% of the blinded cases, the epilepsy surgery team reported that they would not have recommended SEEG based on phase I data. SIGNIFICANCE: In patients with BI/U ictal onset on scalp EEG, the likelihood of identifying a single SEEG SOZ, and subsequently achieving seizure freedom, is low. Scalp EEG ictal onset patterns may aid in triaging candidates for invasive evaluation, informing patients regarding presumed SEEG outcome, and avoiding unnecessary surgical procedures.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".