Hippocampal line length rose before stimulation and returned to baseline 1–11 s after the last burst in 8 patients

We measured line length (LL) in stored hippocampal depth recordings from 8 patients with responsive neurostimulation (RNS), using OpenNeuro ds007095 v1.0.0. The dataset contains 6,019 episodes; 3,263 had the 40-s stimulation-free baseline required by the prespecified window rule. LL in the 5 s before the first burst was higher than baseline in all 8 patients (mean patient log ratio +0.176, about +19%; exact two-sided sign-flip p = 0.0078). From 1 to 11 s after the last burst, LL was at baseline (mean log ratio −0.001; 3/8 patients above zero; p = 0.875; Holm-adjusted p = 1.0). From 16 to 26 s after the last burst, LL was about 2% below baseline in all 8 patients; this comparison was descriptive and outside the Holm correction family. Burst count was not significantly related to pre- or post-stimulation LL, and did not change significantly over the months of recording. Many episodes began during stimulation; LL is a broad measure, the sample includes only stored episodes from one day per week, there was no sham control, and n = 8. The findings therefore do not establish a causal stimulation effect.

hippocampus · responsive neurostimulation · line length · intracranial EEG · closed-loop stimulation · epilepsy · OpenNeuro · stored episodes