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WAUC Dataset

"WAUC: A Multi-Modal Database for Mental Workload Assessment Under Physical Activity"

Overview

WAUC is a large multimodal database for mental Workload Assessment Under physical aCtivity. It uniquely addresses the challenge of monitoring cognitive load when the user is simultaneously physically active - a scenario directly relevant to many real-world deployments, including military operators, industrial workers, and physically active emergency responders.

Study Design

  • 48 participants - the largest participant count across the datasets in this project
  • Cognitive task: NASA MATB-II (Multi-Attribute Task Battery II) - a realistic multi-task cognitive battery originally developed to simulate aircraft monitoring. Participants simultaneously manage system monitoring, tracking, communications, and resource management.
  • Three physical activity conditions designed to introduce motion artefacts and physiological confounds:
Condition Activity Speed
Rest (control) Seated None
Stationary bike Cycling Varying speeds
Treadmill Walking/running Varying speeds

This multi-condition design enables systematic study of how motion artefacts interact with cognitive signals, and how physically activity affects the physiological baseline for cognitive state prediction.

Cognitive Labels

Instrument Description Timing
NASA-TLX Post-section workload rating across all six dimensions After each experimental section
Borg Fatigue Scale Physical fatigue self-rating After each physical activity section

Sensor Suite

WAUC is the most comprehensively instrumented dataset in this project, with simultaneous recordings across six physiological modalities:

Sensor Signal Sampling Rate Channels
Neuroelectrics Enobio 8 EEG 500 Hz 8 ch: AF8, FP2, FP1, AF7, T10, T9, P4, P3
Empatica E4 Blood Volume Pulse (BVP) 64 Hz 1
Empatica E4 Galvanic Skin Response (GSR) 4 Hz 1
Empatica E4 Skin temperature 4 Hz 1
Empatica E4 Accelerometry (3-axis) 32 Hz 3
Bioharness 3 ECG 250 Hz 1
Bioharness 3 Respiration rate 25 Hz 1
Bioharness 3 Accelerometry (3-axis) 18 Hz 3

Enobio 8 Electrode Coverage

The 8 electrodes (AF7, AF8, FP1, FP2, T9, T10, P3, P4) cover:

  • Frontal poles (FP1, FP2) - prefrontal cortex; decision-making and working memory.
  • Anterior frontal (AF7, AF8) - frontal lobe activity adjacent to PFC.
  • Temporal (T9, T10) - memory and emotion.
  • Parietal (P3, P4) - spatial processing, attention.

This placement overlaps significantly with the NASA-TLX stressor-electrode mappings for Mental Demand (frontal), Effort (frontal + parietal), and Frustration (frontal + temporal).

Data Quality Notes

Subject Issue
S20 Bioharness 3 not present - no ECG or respiration data
S25 Empatica E4 not present - no BVP, GSR, temperature, or wrist accelerometry
S28 No subjective metrics collected - cannot be used for supervised fine-tuning

Why WAUC is Valuable

Property Value for Brain FM
48 participants Largest participant count; maximises demographic diversity for fine-tuning
6 simultaneous modalities Gold standard for multimodal fusion and cross-modal alignment research
Physical activity conditions Enables study and mitigation of motion artefacts in both EEG and PPG
ECG included Primary source for ECG cross-modal alignment with EEG
NASA MATB-II task Realistic multi-attribute monitoring task; high face validity

Relevance to the Brain FM Project

WAUC serves multiple roles:

  1. EEG pre-training data - 48 participants of Enobio 8 EEG during cognitive tasks.
  2. Multimodal alignment - simultaneous EEG + BVP + ECG enables three-way cross-modal alignment.
  3. Motion artefact robustness testing - physical activity conditions test the BFM's resilience to motion-corrupted signals.
  4. Device agnosticism evaluation - Enobio 8 uses different electrode positions and sampling rate (500 Hz) from UNIVERSE's Muse S (256 Hz); combining them tests device agnosticism.