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

Q: What is the clinical evidence from this study?

Population: Healthy adults undergoing cardiac monitoring (n=30). Intervention: Finger-to-ear ECG earbuds across four finger-ear geometries (lFlE, rFlE, lFrE, rFrE) and three disturbance conditions (music, talking, walking) vs. 3-lead chest-reference ECG (Lead I). Primary outcome: R peak detection F1 score (left finger to left ear [lFlE] configuration).

Q: What does this research mean for the field?

Earbud-based finger-to-ear ECG utilizing left-finger contact configurations achieves robust heartbeat detection (F1 > 99%) and accurate waveform morphology preservation, whereas right-finger contacts and walking cause severe signal degradation. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Philipp Lepold; Paula Breitling; Jonas Hummel; Tobias Röddiger; Michael Beigl

doi:10.5445/ir/1000197518

November 6, 2026Open Access

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

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Key result

Left-finger-to-ear ECG achieves ~99% R-peak detection accuracy and correlates strongly with chest ECG.

n=30

Why the study?

Ear-ECG enables unobtrusive cardiac monitoring, but existing approaches often struggle with low signal amplitudes and limited morphology preservation.

Does a finger-to-ear earbud ECG system accurately detect heartbeats and preserve ECG waveform morphology compared to a 3-lead chest-reference ECG in healthy adults across different finger-ear geometries and everyday disturbances?

Key Points

To evaluate a finger-to-ear ECG paradigm integrating an in-ear electrode with a housing finger-contact electrode in speaker-equipped earbuds across different geometries and disturbances.
Tested 30 adult participants (mean age 26.57 ± 5.13 years; 21 males, 9 females) across four finger-to-ear electrode geometries (lFlE, rFlE, lFrE, rFrE) against a chest-reference ECG.
Assessed signal fidelity and R-peak detection under stationary conditions and during real-world disturbances, including music playback, talking, and walking.
Evaluated waveform morphology and heartbeat rhythm metrics using Pearson correlation coefficients with Bonferroni correction.
Left-finger configurations achieved R-peak detection F1-scores >99% (lFlE: 99.34%; lFrE: 99.30%), with cross-body setup lFrE showing the highest waveform correlation (r = 0.92) and lowest heart rate error (0.05 bpm).
Right-finger configurations exhibited poor morphology preservation and severe performance drops, yielding negative waveform correlations (rFlE: r = -0.30; rFrE: r = -0.27) and lower F1-scores (55.59% and 80.95%).
Talking and music playback maintained high heartbeat detection performance (F1-scores of 99.05% and 94.54%, respectively), whereas walking caused severe signal degradation (F1-score of 54.96%).

Structured PICO

Does a finger-to-ear earbud ECG system accurately detect heartbeats and preserve ECG waveform morphology compared to a 3-lead chest-reference ECG in healthy adults across different finger-ear geometries and everyday disturbances?

P

Population

30 young, healthy adults (mean age 26.57 years, 30% female, 93.3% right-handed) evaluated across seven 180-second ECG recording conditions.

I

Intervention

Wearable finger-to-ear ECG earbud system (combining an in-ear electrode with a rear housing finger-contact dry conductive polymer electrode coated with silver/silver-chloride) evaluated across four geometries (left finger & left ear [lFlE], right finger & left ear [rFlE], left finger & right ear [lFrE], right finger & right ear [rFrE]) and three disturbance conditions (music playback at 50% volume, talking/reading aloud, and walking) for 180 seconds per condition

C

Comparator

Simultaneous 3-lead chest-reference ECG (Faros, Bittium) using silver/silver-chloride wet electrodes (specifically compared against lead I)

O

Outcome

R peak heartbeat detection performance (precision, recall, F1 score, absolute heart rate error, absolute HRV error) and ECG waveform morphology similarity (Pearson correlation r, P wave amplitude, QRS complex amplitude, PR interval, QRS duration, QT interval)surrogate

Left-finger-to-ear earbud ECG provides high-fidelity heartbeat detection (F1 >99%) and preserves ventricular ECG morphology comparable to lead I chest ECG during stationary conditions, talking, and music playback, offering a viable paradigm for opportunistic cardiac sensing in earables.

Limitations

Requires active finger contact, making passive long-term monitoring impossible
Study population consisted only of young, healthy adults, limiting generalisability to broader populations
Current prototype is not yet a fully self-contained true-wireless wearable system and lacks active grounding (DRL)
Clinical suitability for diagnostic interpretation has not yet been validated by medical experts
Walking introduced severe motion artefacts that substantially degraded waveform morphology (F1-score 54.96%)

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Implication

Left-finger earbud ECG yields high R-peak fidelity in controlled settings; leaves open wearable monitoring pending larger, diverse validation trials.

Abstract

Ear-ECG enables unobtrusive cardiac monitoring, but existing approaches often struggle with low signal amplitudes and limited morphology preservation. We evaluate a finger-to-ear ECG paradigm that combines an in-ear electrode with a rear housing finger-contact electrode in a speaker-equipped earbud. A study with 30 participants investigated four finger-to-ear electrode geometries against chest-reference ECG and additionally assessed robustness under music playback, talking, and walking disturbances. Left-finger configurations achieved R peak detection F1-scores >99% with high agreement of key ECG morphology features. In contrast, right finger configurations as well as walking led to severe signal degradation. The results reveal a trade-off: while cross-body setups provided the highest signal fidelity, users preferred same-side contacts for comfort reasons. This establishes finger-to-ear ECG as a robust, morphology-aware paradigm for opportunistic sensing in earables.

Discussion

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Cite This Study

Lepold et al. (2026) studied Healthy adults undergoing cardiac monitoring (n=30). Finger-to-ear ECG earbuds across four finger-ear geometries (lFlE, rFlE, lFrE, rFrE) and three disturbance conditions (music, talking, walking) vs. 3-lead chest-reference ECG (Lead I) was evaluated on R peak detection F1 score (left finger to left ear [lFlE] configuration). Finger-to-ear ECG using left-finger configurations achieved R peak detection F1-scores >99% and strong waveform correlation with chest ECG.

synapsesocial.com/papers/6aefbd4950d2071ffda4bbe8 https://doi.org/10.5445/ir/1000197518

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

Key Points

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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

Key Points

Structured PICO

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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