Finger-to-Ear ECG: Systematic Evaluation of an Earbud-Based Cardiac Monitoring Approach

Summary

This paper evaluates a finger-to-ear ECG approach using earbuds, finding that left-finger configurations achieve high accuracy and morphology preservation, establishing it as a robust method for opportunistic cardiac sensing despite some trade-offs with user comfort.

Key findings

• Left-finger configurations achieved R peak detection F1-scores >99% with high agreement of key ECG morphology features.
• Right finger configurations and walking disturbances severely degraded signal quality.
• Cross-body setups yielded the highest signal fidelity, but same-side contacts were preferred for comfort.
• The finger-to-ear ECG paradigm is robust and morphology-aware for opportunistic sensing in earables.

Methods

• Developed a finger-to-ear ECG system using an earbud with in-ear and rear housing electrodes.
• Recruited 30 participants for the study.
• Investigated four finger-to-ear electrode geometries.
• Compared earbud ECG against chest-reference ECG and assessed performance under music, talking, and walking conditions.

Limitations

• Right-finger configurations and walking conditions led to significant signal degradation.
• A trade-off exists between signal fidelity (cross-body) and user comfort (same-side contacts).
• The study focused on a specific earbud design and electrode configurations.

Applications

• Opportunistic cardiac monitoring in earable devices.
• Development of unobtrusive wearable health sensors.
• Personalized auditory healthcare platforms.