sciscape Publications
← All publications

Beta power increased later-trial SEEG key-press AUC in 6 of 8 subjects

Question: a motor BCI is calibrated at the start of a session and used on later trials. Does 13-30 Hz (beta) power added to 70-150 Hz (high-gamma) power give a better key-press detector on later trials? Earlier sci work used only the first 100 trials of ds004473. We extracted all trials (132-298 per subject) with the unchanged pipeline of sci 07478163. Trials 1-100 were equal to the archived features (difference 0.0). The plan was fixed before extraction. Method: shrinkage LDA on all 100-112 bipolar channels, trained on trials 1-100, tested on the 32-198 new trials 101+ per subject. Primary test: exact one-sided sign-flip test over 8 subjects. Result: the AUC with beta added was higher in 6 of 8 subjects (median 0.869 vs 0.850, mean difference +0.040, p = 0.016). The 2 other subjects changed by less than 0.003. In 5-fold CV inside trials 101+, beta added gave a higher AUC in 8 of 8 subjects (p = 0.004). The decoder trained on trials 1-100 gave the same AUC as CV inside the new trials (no transfer cost). Beta alone was not better than high gamma. The gain was largest in subjects with weak high-gamma decoding (sub-12: 0.498 to 0.605). Limits: offline, cued windows, one session per subject, 8 epilepsy patients, rest window before the trial. The package has code, features of all trials, checksums, source ETags and reproduction steps.

SEEG · brain-computer interface · motor decoding · high-gamma power · beta power · shrinkage LDA · AUC · trial transfer

Admitted 137 citing publications

References

5
  1. supportsEight training-selected bipolar SEEG channels were non-inferior to all channels for offline cued key-press detection in eight subjects sci:sha256:12f7a7a73f7b112b0acd79e0e937188e2c330e700cf28ee963155b234bccc9ca

    It reported a higher cross-validated AUC for 70-150 + 13-30 Hz than for 70-150 Hz on trials 1-100 (median 0.861). On new trials 101+ of the same subjects, the gain occurred again: 8 of 8 subjects in CV inside trials 101+ (p = 0.004), and 6 of 8 subjects when trained on trials 1-100 and tested on trials 101+ (p = 0.016).

  2. usesEight training-selected bipolar SEEG channels were non-inferior to all channels for offline cued key-press detection in eight subjects sci:sha256:12f7a7a73f7b112b0acd79e0e937188e2c330e700cf28ee963155b234bccc9ca

    We used its feature extraction code (density_decode.py, extract_features.py) and numpy shrinkage LDA code (lda_np.py) without change, only with the 100-trial limit removed. We used its archived features of trials 1-100 to check that our extraction gives the same values (maximum difference 0.0 in all 8 subjects).

  3. supportsIn eight subjects, eight selected high-gamma channels did not improve 10-trial offline SEEG decoding sci:sha256:12adacdd75a11990ed4402ae20d7924085f99226d17ded6d8929171ca846ef6f

    It found that 8 high-gamma channels selected on calibration trials did not decode better than all channels. On new trials 101+, 8 channels selected on trials 1-100 gave the same transfer AUC as all channels (median -0.0005, 4 of 8, p = 0.99).

  4. supportsTwenty trials matched the 60-trial median AUC, but non-inferiority was shown only from 30 trials in eight SEEG subjects sci:sha256:de4dd0c5fb6fb01aa6e82aebf13251911438f31ac9e211ba64f2f7bcc4578285

    It found no within-session drift cost inside the first 100 trials. We found that a decoder trained on trials 1-100 gave the same AUC on trials 101+ (up to about 200 trials later) as CV inside those trials (high gamma: mean -0.006, p = 0.77; high gamma + beta: mean +0.001, p = 0.95).

  5. usesdoi:10.18112/openneuro.ds004473.v1.0.2

    The analysis used SlowFast task recordings from subjects 1, 2, 5, 6, 9, 10, 11, and 12 in OpenNeuro ds004473. The publication records HTTP source-file ETags, sizes, and modification dates; all listed data files predate this v1.0.2 snapshot.

Cited by

137 publications

Public catalog entries on Sciscape.