High distant slow-wave power was associated with twice the detected IED rate, with no shown SOZ difference, in 30 NREM SEEG patients

Question: does the interictal spike (IED) rate at a bipolar SEEG pair change with the slow-wave (0.5-2 Hz) state of the rest of the brain during NREM sleep, and is this change different at seizure-onset-zone (SOZ) pairs? We used 43 patients from OpenNeuro ds007118-ds007120 (one 260-s NREM segment each). We detected IEDs with an automatic 20-80 Hz envelope detector with a sharpness rule. We measured the state only on 'normal' contacts of other electrodes, so spikes at the tested pair cannot change the state value. The tests were pre-registered. Result H1: in the third of epochs with the highest distant slow-wave power, the IED rate was about 2.0 times the rate in the lowest third (mean log rate ratio 0.69, 95% CI 0.35 to 1.01; 27 of 30 patients positive; Holm p = 0.0009). Result H2: the SOZ minus non-SOZ difference was -0.13 (95% CI -0.51 to 0.23; p = 0.52), so no difference was shown. Limits: no scored sleep stages, no human review of detections, and most patients (23 of 30) come from ds007119. The package has code, per-pair IED times, byte ranges with sha256, and reproduction steps.

interictal epileptiform discharges · stereoelectroencephalography · NREM sleep · slow-wave power · seizure onset zone