ECG signal quality in intermittent long-term dry electrode recordings with controlled motion artifacts

Area of Science:

• Biomedical Engineering
• Wearable Technology
• Biosignal Processing

Background:

• Wearable electrocardiogram (ECG) monitoring is increasingly vital for consumer and medical applications.
• Data quality in wearable ECG hinges on electrode properties and skin interface.
• Dry electrodes offer user convenience and skin compatibility for ECG monitoring during low-intensity activities.

Purpose of the Study:

• To investigate motion artifact-resistant dry electrode materials for wearable ECG monitoring.
• To compare the performance of porous (conductive polymer, silver fabric) and solid (stainless steel, silver, platinum) electrodes.
• To assess the impact of electrode movement on signal quality.

Main Methods:

• ECG data acquisition from test subjects using various dry electrode materials.
• Conducted a 10-min stationary settling test and a 48-h intermittent long-term test.
• Measured signal-to-noise ratio (SNR) and skin-electrode interface impedance.
• Included stationary and controlled motion artifact tests in the long-term evaluation.

Main Results:

• All electrode types showed increased SNR during the settling test, with further elevation in the long-term test.
• Electrode movement significantly reduced SNR across all materials.
• Solid electrodes generally exhibited higher SNR and lower skin-electrode impedance than porous electrodes.
• In stationary tests, stainless steel yielded the highest SNR, followed by platinum, silver, conductive polymer, and conductive fabric.

Conclusions:

• Solid dry electrodes, particularly platinum and stainless steel, demonstrate superior performance for motion artifact-resistant wearable ECG monitoring.
• Material choice and electrode-skin interaction are critical for maintaining high-quality ECG signals during movement.
• These findings inform the selection of optimal dry electrode materials for robust long-term wearable health monitoring.