Decoder evaluation across recording days
Two fixed classifiers, their confusion patterns, and the uncertainty behind a change in ordering.
RESEARCH AT DAYBREAK
Exploring more reliable EEG decoding with less repeated calibration. A research project built around a simple question: what should a decoder carry into the next day?
THE QUESTION THAT DRIVES US
What would it take for a neural decoder to learn today
and need less relearning tomorrow?
THE OPEN-SOURCE LEARNING LAB
Change circuit parameters, follow population activity, and connect differential equations to phase portraits and stability.
These are simplified mathematical simulations, not measured EEG. The complete explorer and its MIT-licensed source remain available.
Open the Dynamics Explorer01 / OUR DIRECTION
From supervised adaptation to learned augmentation. Each comparison tracks calibration cost, participant-level trade-offs, and uncertainty.
Comparisons completed · Study 002
Our calibration study broadened the comparison beyond the original bandpower baseline to spatial and covariance-based pipelines. The same recording protocol lets us examine where the representation matters before adding a more complicated adaptation method.
Does a proposed method improve on a strong, simpler baseline under the same data access?
02 / THE CURRENT EXPERIMENT
Study 007 compared generated examples with real-only training and simple augmentation. This first pilot found lower average accuracy with generated EEG at the fixed primary budget.
Three training arms share the same compact EEGNet-style decoder, real-label budget, source checkpoint, and optimization budget. They differ in the examples used during adaptation.
The learned generator produces covariance patterns and uses them to synthesize band-limited EEG. This is a constrained conditional VAE experiment; it does not generate the full range of brain dynamics.
Generated augmentation performed worse on average than real-only training at the fixed 24-label budget in this eight-person pilot.
50% is the two-class chance reference. These eight participants were previously examined in Studies005–006. Three seeds quantify training variability; they do not make 24 independent people. The classical reference is recomputed on this pilot’s inputs.
FIXED PRIMARY COMPARISON
Generated augmentation versus real-only EEGNet · 24 real calibration trials
Descriptive 95% participant interval:
−4.31 to −0.42 pp
1 improved · 7 worsened · 0 tied
After averaging three seeds per participant
Small, nonrandom development cohort. The interval assumes independent, approximately normally distributed participant differences. It does not establish reliability for new people or future days.
| Participant | Real only | Simple | Generated | Difference |
|---|---|---|---|---|
| 2 | 59.62 | 59.62 | 53.85 | −5.77 |
| 3 | 86.57 | 86.57 | 83.84 | −2.73 |
| 4 | 52.88 | 53.64 | 49.90 | −2.98 |
| 5 | 61.87 | 61.67 | 62.37 | +0.51 |
| 6 | 82.47 | 82.47 | 77.22 | −5.25 |
| 7 | 52.63 | 52.07 | 52.27 | −0.35 |
| 8 | 51.87 | 51.11 | 49.60 | −2.27 |
| 9 | 60.15 | 60.15 | 60.05 | −0.10 |
Fixed protocol · Real test data · Participant-level reporting
Design snapshot · ZIP ↗Code + results · ZIP ↗PREVIOUS FINDING / STUDY 006
Across 53 OpenBMI participants, the gate reached 67.74% mean balanced accuracy, versus 71.87% for always updating with 24 labels. Mean loss burden fell by 20.6%, below the fixed 25% target. Both engineering targets failed.
The gate trained on 16 labels and spent 8 on selection. These are development results on the same participants as Study005. The simpler supervised update remains the benchmark.
Read the complete result ↗THE RESEARCH RECORD
Completed experiments remain available, including unfavorable comparisons and the assumptions behind each result.
Can blending an alignment step reduce a known failure without losing what a simple label-informed update already achieves?
At a budget of 8 original trials, participant 3 improved from 52.00% with full alignment + update to 78.64% with conservative alignment + update. Updating alone reached 79.53%. Participants 1 and 2 performed worse with the conservative version than with full alignment at that budget.
Conservative alignment mitigated a known failure in this development analysis. It did not demonstrate an advantage over updating alone at the primary budget.
20–24 accepted calibration trials per participant after excluding artifact-flagged trials.
Budget 24 original trials. Equal-person mean for participants one through four.
Dashed reference: 25% uniform guessing. All four participants were previously examined development data. These chart views are descriptive; changing the view does not change the fixed primary comparison below.
FIXED PRIMARY COMPARISON
Conservative alignment + update
versus updating alone
Conditional 95% interval: −0.67 to +0.61 pp
Equal-person mean, participants 1–4
Budget: 24 original calibration trials
Means: 67.47% updating alone · 67.47% conservative alignment + update.
No demonstrated advantage.The interval describes test-run resampling for these four participants, fixed models and calibration prefixes. It does not measure uncertainty for new participants or future days.
Historical development analysis Study 003 used previously examined participants 1–4. Study 004 subsequently evaluated the frozen method on reserved participants 5–9. Rerunning identical data checks reproducibility, not generalization.
THE RESEARCH RECORD
Read the findings, inspect the code,
and keep the limitations in view.
Two fixed classifiers, their confusion patterns, and the uncertainty behind a change in ordering.
Broader pipeline comparisons and adaptation strategies under defined access to calibration data.
A targeted failure mitigation, compared with full alignment and updating alone. The primary advantage remains unproven.
Five BNCI participants. Conservative alignment minus updating: −0.765 pp; 95% participant interval −2.250 to +0.720. No demonstrated added benefit.
53 reserved participants. At 24 calibration labels, updating gained +6.38 pp on average; 38 improved, 14 worsened, and one tied.
The gate missed both targets: −4.14 pp versus always-update24, with a 20.6% reduction in mean loss burden. Exploratory reuse of Study 005 participants.
03 / THE PATH FORWARD
The evidence has expanded to a second dataset. The next method still has to earn its place against a simpler baseline, then face new sessions and new people.
Document the data, exclusions, model choices, errors, and uncertainty in a runnable notebook and working paper.
Compare established pipelines and adaptation strategies at defined calibration budgets on participants 1–4.
Mitigate a known failure and compare with update-only. The primary 24-trial result shows no demonstrated advantage.
Evaluate reserved BNCI participants, test supervised updating on OpenBMI, and retain the update gate’s failed development screen.
Compare real-only, simple, and generated training examples at the same real-label budget. Use this pilot to decide whether a larger, independently evaluated study is warranted.
A FEW USEFUL DISTINCTIONS
We are investigating EEG decoding methods that need less repeated calibration. This section preserves our reproducible offline studies. Decoder Studio turns evaluation concepts into a guided browser workspace, while the research explores methods we have not established as superior commercial decoders or clinical systems.
Study 004 found no demonstrated benefit from conservative alignment over updating alone on five reserved BNCI participants. Study 005 tested supervised updating on an independent dataset, OpenBMI: the mean gain at 24 labels was 6.38 percentage points across 53 participants, but 14 people worsened. Study 006 then reused those people to test an update gate; it missed both development targets.
No. It is a fixed eight-person development pilot using OpenBMI participants already examined in Studies 005 and 006. The protocol was saved before the new computation, but this is not external preregistration or prospective validation. Training seeds and generated examples do not increase the number of independent people.
A small conditional variational autoencoder learns covariance patterns from permitted real training data. A stochastic synthesis step converts those patterns into band-limited signals. It is a restricted generator, not a model of complete brain dynamics. Generated examples are used only for training; performance is measured on real later trials.
A worthwhile pilot would test a fixed decoder against that team’s baseline on new sessions, measuring accuracy, calibration time, individual regressions, and integration cost. Our present work provides an inspectable research starting point, not a promise of those benefits.
LET’S START A CONVERSATION
Have a research question, a potential collaboration, or feedback on the work? Get in touch with our team.