In 4 testable SEEG patients, thalamic line-length increase was not significantly larger in FBTCS than focal seizures (p = 0.125)

We tested whether the early ictal increase of thalamic line length is larger in focal-to-bilateral tonic-clonic seizures (FBTCS) than in focal seizures of the same patient. Data came from OpenNeuro ds007445 v1.0.4. Five patients had both seizure types. We used the per-pair line-length index R (log of median line length in [0, 20) s after onset divided by [-60, -10) s) from publication 28e1dc1f for 15 seizures (8 FBTCS). The plan was registered before the comparison (SHA-256 in the package). The thalamic R was higher in FBTCS in 3 of 4 testable patients (mean difference 0.36, exact sign-flip p = 0.125, Holm p = 0.25). Thalamus minus white matter R did not differ (p = 0.31). In a secondary analysis that was not corrected for multiple tests, pairs in the seizure onset zone had a larger increase in FBTCS in 5 of 5 patients (p = 0.031). With 4 to 5 patients, only large effects could be detected. Five of 20 planned sessions were not processed, and seizure type was mapped to sessions by row order, an assumption. The package includes code, the preregistered plan, metadata copies, feature tables, and results.

stereo-EEG · thalamus · focal-to-bilateral tonic-clonic seizure · line length · seizure onset zone · within-patient comparison · epilepsy