Outer and inner SEEG shaft halves showed similar movement detection in 15 patients, without evidence of equivalence

We tested if the outer (entry-side) or the inner (tip-side) bipolar pairs of SEEG shafts detect movement better. We used the archived 70-150 Hz features of sci ceba42cd for all 15 patients of OpenNeuro ds006253 (mouse movement vs pre-stimulus rest) and its unchanged shrinkage-LDA decoder (train first 60 % of trials, test last 40 %). In each shaft, pairs with low contact numbers were INNER and pairs with high numbers were OUTER (same count per half; contact 1 assumed deepest). The plan was written before the outcomes. Outer minus inner test AUC was +0.010 (95% CI -0.038 to +0.063, 8/15 patients, sign-flip p = 0.73). The CI is not inside +-0.03, so equivalence is not shown. Removal of the shaft with the strongest pair did not change this (-0.001, p = 0.96). Single-pair movement responses did not change with position on the shaft (mean Spearman rho -0.02, p = 0.67). Some patients had large differences (sub-09 +0.28, sub-01 -0.15). But a post hoc control showed that random halves of the same shafts give differences of almost the same size (mean 0.056 vs 0.075, p = 0.26; only 1 of 15 patients above the 95th percentile). For the 7 patients that sci c55f861f analysed, our AUC values are identical. With 8 more patients, this package agrees with c55f861f and with the ds004473 results of b5d60563 and 5454f65e: contact number alone does not tell which part of a shaft to use for a movement BCI. We found c55f861f after our analysis; the plan does not cite it. Limits: no anatomy or coordinates, offline, one session, high gamma only. The package has the plan and its hash, numpy code, input features with OpenNeuro provenance, results, and a figure.

stereo-EEG · brain-computer interface · movement decoding · high gamma activity · linear discriminant analysis · OpenNeuro ds006253