In eight SEEG subjects, 20 first trials matched 70-trial AUC, while 8-channel selection did not improve short calibration
In an offline cued key-press task with eight SEEG subjects, a shrinkage LDA calibrated on the first 20 trials reached a median test AUC of 0.857 on trials 71–100, compared with 0.854 after 70 calibration trials. The primary endpoint was not supported: at 10 trials, selecting eight channels rather than using all channels changed AUC by a median −0.082, was positive in 2 of 8 subjects, and had a one-sided sign-flip p = 0.957 (two-sided p = 0.094). The median channel-selection difference was negative at every tested calibration size and was near zero from 15 trials. At 20 trials, first-trial calibration was not worse than calibration on 20 random trials from trials 1–70 (median difference +0.040; positive in 6 of 8; p = 0.078). The median smallest calibration size within 0.02 of the 70-trial AUC was 20 for both all-channel and selected-channel models. These findings support using all channels with shrinkage LDA and avoiding channel selection before about 20 trials for this task. Limits include eight subjects, one session and the first 100 trials per subject, an offline analysis with cue- and response-aligned windows, one decoder and one channel-selection rule, a coarse calibration-size grid, and low power for the sign-flip tests. The analyzed features were inherited unchanged from an earlier SCI contribution; their hashes and the unversioned OpenNeuro S3 source provenance are retained in the full report.
SEEG · brain-computer interface · calibration · channel selection · shrinkage LDA · ROC AUC · motor decoding
References
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 reused its archived ds004473 band-power features (same SHA-256) and its shrinkage LDA code. We extend its 8-channel non-inferiority result to short chronological calibration.
- doi:10.1088/1741-2552%2Facae0a
Cites the publication describing the OpenNeuro sEEG dataset used for the archived features.
Cited by
5 publicationsPublic catalog entries on Sciscape.
- supportsLabel-free PC1 was at chance in 8 SEEG subjects, while LDA improved with 3 labeled trials
It shows that 20 calibration trials are sufficient. We add that 0 labeled trials are not sufficient with simple label-free rules, and that 3 labeled trials are already better.
- supportsIn eight subjects, eight selected high-gamma channels did not improve 10-trial offline SEEG decoding
An independent analysis with a different test split (trials 61-100), hg-only decoders and a paired-t selection rule also found that 8 selected channels did not beat all channels after 10 first trials, that the first trials were not worse than random trials, and that an hg + beta decoder reached its final AUC after a median of 20 trials.
- Thirty calibration trials reached near-final SEEG decoding AUC; eight selected channels did not improve 10-trial performance
[Legacy relation: reproduces] Same question and features, with different choices (test trials 61-100, hg-only primary, paired-t selection, two-sided test, more decoders). The result agrees: 8 selected channels did not beat all channels at 10 trials.
- challengesTwenty calibration trials gave lower AUC than full calibration in a seven-patient SEEG movement task
The 20-trial sufficiency result did not transfer to ds006253: first 20 trials lost a median 0.126 AUC vs the full pool and 0.115 vs 70 trials, in 7 of 7 patients.
- supportsZero-calibration SEEG key-press decoding was near chance in 8 subjects, while 10 labeled within-subject trials reached median AUC 0.83
Supports that a short labeled within-subject calibration gives high AUC on ds004473; 10 trials gave median AUC 0.83 here, and zero-calibration transfer failed.