# Arithmetic & rest on EEGMAT

Core-matrix protocol · Transfer to a new person

Everything that produced the scores below — cohort, split, electrodes, window, what each method was allowed to learn, and what guessing would score — as the released protocol file states it. Compare scores within this protocol only.

## The protocol at a glance

- Task: Serial subtraction versus resting EEG
- Evaluation: Transfer to a new person
- Dataset: [EEGMAT](https://bci.report/datasets/eegmat/)
- People: 36
- Data: 2,160 epochs · 5 participant-disjoint folds
- Input: 19 channels · 2-second windows
- Chance level: 50.0%
- Metrics: Balanced accuracy (primary) · Macro F1 (secondary)

## Results

Every method run under this protocol, with the score the released results file holds. Compare down this table only: other protocols differ in cohort, electrodes, window or chance level.

**Balanced accuracy, every method under this protocol.** Dot: the estimate; line: descriptive 95% interval; dashed line: chance level.

- Spectral ridge: 56.8% (54.6%–58.9%)
- LaBraM: 64.6% (60.5%–68.6%)
- CBraMod: 62.3% (58.1%–66.5%)
- EEGNet: 67.6% (62.8%–72.5%)

| Method | Training mode | Balanced accuracy | Macro F1 | Channels | People | Scoring time |
| --- | --- | --- | --- | --- | --- | --- |
| Spectral ridge — Classical method | Supervised fit | 56.8% (54.6%–58.9%) | 0.558 — Mean across held-out participants | 19 | 36 | 0.6 s |
| [LaBraM](https://bci.report/methods/labram/) — Foundation model | Frozen encoder + ridge head | 64.6% (60.5%–68.6%) | 0.620 — Mean across held-out participants | 19 | 36 | 2.1 s |
| [CBraMod](https://bci.report/methods/cbramod/) — Foundation model | Frozen encoder + ridge head | 62.3% (58.1%–66.5%) | 0.602 — Mean across held-out participants | 19 | 36 | 6.1 s |
| [EEGNet](https://bci.report/methods/eegnet/) — Compact model | Scratch · 20 epochs | 67.6% (62.8%–72.5%) Single seed — the highest of the seeds run (see Stability) | 0.637 — Mean across held-out participants | 19 | 36 | 117.7 s |

Scoring time includes fitting and prediction, may include accelerator waiting, and excludes data preparation. It is configuration-specific, not a hardware benchmark.

**Not run under this protocol:** [CSP+LDA](https://bci.report/methods/csp-lda/), [ShallowFBCSPNet](https://bci.report/methods/shallowfbcspnet/), [Deep4Net](https://bci.report/methods/deep4net/), [Standard CCA](https://bci.report/methods/cca/), Temporal ridge. A method missing here was not run on this protocol — that is not a failure.

## Read with care

Thirty nonoverlapping 2-second windows from each of two conditions per person. Published signals were already cleaned with ICA; task performance groups are not evaluated.

### The protocol, step by step

- 5 participant-disjoint folds. All recordings from a person stay together. Each person contributes to the held-out predictions once.
- First 60 s of each recording; 30 contiguous nonoverlapping 2 s windows; exclude A2-A1 ear-difference and ECG; EDF physical volts converted to microvolts; subtract each channel's window mean; no rejection, filtering, resampling, or learned preprocessing.
- One fixed seed (20260919); no early stopping or test-based tuning. EEGNet trains for 20 epochs per fold. Frozen encoders use training-only standardized ridge heads (alpha 100).
- Labels: pre-task-rest, mental-arithmetic.
- Uniform-guessing reference: 50.00%. Scores weight participants equally. Intervals describe participant variation; cross-validation training sets overlap.
- The benchmark detects condition (rest versus serial subtraction), not the good/bad count-quality participant grouping.
- Only the first documented 60 seconds is retained even though EDF containers are longer.
- The source README reports prior ICA artifact removal, so these are not untouched acquisition signals.
- Open Data Commons Attribution License v1.0 applies; retain PhysioNet attribution.
- EEGNet three-seed mean 67.52%; sample SD 0.14 percentage points; range 67.36–67.64%. Main table retains the original fixed seed; this is not a confidence interval.

### Stability

EEGNet three-seed mean 67.52%; sample SD 0.14 percentage points; range 67.36–67.64%. Main table retains the original fixed seed; this is not a confidence interval.

Seeds run for EEGNet: 67.64% · 67.55% · 67.36%; mean 67.52%

Same participants, folds, preprocessing and 20-epoch budget. Three seeds measure initialization variability, not population uncertainty. Main table retains its preselected seed; no best-seed selection.

### Pretraining exposure

Unknown unless explicitly documented; no unseen-pretraining claim.

### Notes on the methods

- One fixed configuration. Foundation encoders remain frozen; small networks train from scratch. These scores do not establish optimal fine-tuned performance. No individual predictions or participant-level results are distributed.
- One fixed configuration. Foundation encoders remain frozen; small networks train from scratch. These scores do not establish optimal fine-tuned performance. No individual predictions or participant-level results are distributed. EEGNet three-seed mean 67.52%; sample SD 0.14 percentage points; range 67.36–67.64%. Main table retains the original fixed seed; this is not a confidence interval.

### Model terms

- **Spectral ridge**: Trained from scratch / deterministic reference; no third-party pretrained weights. Braindecode BSD-3-Clause; MNE/scikit-learn BSD where used.
- **LaBraM**: Code/repository: MIT · Checkpoint: committed in that repository; no separate weight terms
- **CBraMod**: Code: MIT · Weights: Apache-2.0 (official model card)
- **EEGNet**: Trained from scratch / deterministic reference; no third-party pretrained weights. Braindecode BSD-3-Clause; MNE/scikit-learn BSD where used.

## Source and licence

### EEGMAT

**Credit** Igor Zyma, Ivan Seleznov, Anton Popov, Mariia Chernykh, Oleksii Shpenkov · EEG During Mental Arithmetic Tasks 1.0.0, PhysioNet, doi:10.13026/C2JQ1P. Study: Zyma et al. (2019), doi:10.3390/data4010014. PhysioNet platform: Pollard et al. (2026), doi:10.1038/s44360-026-00096-z.

**Licence** [Open Data Commons Attribution License 1.0 ↗](https://opendatacommons.org/licenses/by/1-0/)

[Dataset record ↗](https://physionet.org/content/eegmat/1.0.0/) · [Every result on this dataset →](https://bci.report/datasets/eegmat/)

BCI Report does not redistribute any recording. These are aggregate measurements computed by BCI Report under the licence above; the data belong to the people credited.

**Permitted scope** Personal noncommercial research; aggregate results only

**Privacy** Only cohort aggregates are published here: no recording, no participant identifier, no per-person score. [The full review note is in the protocol JSON ↓](https://bci.report/data/arithmetic-rest-protocol.json)

**Public-data register note** Attribution license and study-specific approval/consent are documented; eligibility assumes aggregate-only output and exclusion of subject-info fields.

**Rights reviewed** 2026-09-20 · against [physionet.org ↗](https://physionet.org/content/eegmat/1.0.0/) · [www.mdpi.com ↗](https://www.mdpi.com/2306-5729/4/1/14) · [opendatacommons.org ↗](https://opendatacommons.org/licenses/by/1-0/)

## Reproducibility record

- Protocol id: `parallel-fixed-subject-folds-v1/physionet-eegmat-1.0.0`
- Dataset release: PhysioNet EEG During Mental Arithmetic Tasks 1.0.0 · 1.0.0
- Hardware: Apple M5 / MPS
- Scoring stage sum: 126.5 s · may include accelerator waiting
- Audit record SHA-256: `2d0e4cec78c8d6e5bfc9f5390ba161f4308759e02feffbb8645d6983d9093292`
- Summary SHA-256: `ab607e749da1eedcf88441c5b6fd0db55e2ebae0bbd91d6d18e508605eef625b`
- Protocol SHA-256: `5d53ccbd5a00763908162f0b700c0a3236e0d4f9d43b08e42ee31a2ef01aefbf`

## Downloads

- [Results · CSV ↓](https://bci.report/data/arithmetic-rest-results.csv)
- [Protocol · JSON ↓](https://bci.report/data/arithmetic-rest-protocol.json)
- [Core matrix · JSON ↓](https://bci.report/data/experiments.json)

### Other protocols

- [Motor imagery & rest on ds003810](https://bci.report/protocols/mi-rest/)
- [Idle & command on ds005342](https://bci.report/protocols/idle/)
- [SSVEP · 8 channels on BETA](https://bci.report/protocols/beta-8ch/)
- [SSVEP · 4 channels on BETA](https://bci.report/protocols/beta-4ch/)
- [P300 target ERP on ds006593](https://bci.report/protocols/p300-target/)
- [Semantic target ERP on TMNRED / ds005383](https://bci.report/protocols/semantic-target/)
- [Sleep staging on EESM19 scalp subset](https://bci.report/protocols/sleep-scalp/)

[All protocols →](https://bci.report/protocols/) · [The core matrix on the home page →](https://bci.report/#overview) · [All datasets →](https://bci.report/datasets/) · [All methods →](https://bci.report/methods/)

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