In 16 patients, thalamic line length was above baseline at seizure start and end, with no clear further increase or post-offset change

We analyzed stereoelectroencephalography from OpenNeuro ds007445 v1.0.4 (42 seizures lasting at least 20 s in 17 patients) to compare bipolar line length (LL) in ipsilateral thalamus, white matter, and seizure-onset zone near seizure onset, before annotated seizure offset, and after offset. The patient was the unit. The plan was fixed and hashed before feature calculation; four primary tests used exact sign-flip tests with Holm correction. Thalamic LL was above baseline at onset (mean log ratio 0.266; 16/16 patients positive) and near offset (0.348; 15/16), both exploratory. The primary tests did not show a clear increase from onset to offset (mean difference 0.081; 8/16 positive; Holm p=0.37), greater late thalamic than white-matter LL (mean difference -0.010; 5/14 positive; Holm p=1), greater thalamic than white-matter growth (mean difference -0.061; 5/14 positive; Holm p=1), or a post-offset thalamic change from baseline (mean 0.002; Holm p=1). Exploratory seizure-onset-zone LL was below baseline after offset (mean -0.771; 3/14 positive; p=0.0024). These data do not show that the end-of-seizure LL rise is specific to thalamus in this measure. Interpretation is limited by small patient counts, clinical offset annotations, 10-s analysis windows, predominantly 200-Hz sampling, filter implementation, and use of LL alone.

stereoelectroencephalography · epilepsy · thalamus · line length · seizure · seizure offset · white matter · signal processing · OpenNeuro