Hearables: feasibility of recording cardiac rhythms from single in-ear locations

Abstract

The ear is well positioned to accommodate both brain and vital signs monitoring, via so-called hearable devices. Consequently, ear-based electroencephalography has recently garnered great interest. However, despite the considerable potential of hearable based cardiac monitoring, the biophysics and characteristic cardiac rhythm of ear-based electrocardiography (ECG) are not yet well understood. To this end, we map the cardiac potential on the ear through volume conductor modelling and measurements on multiple subjects. In addition, in order to demonstrate real-world feasibility of in-ear ECG, measurements are conducted throughout a long-time simulated driving task. As a means of evaluation, the correspondence between the cardiac rhythms obtained via the ear-based and standard Lead I measurements, with respect to the shape and timing of the cardiac rhythm, is verified through three measures of similarity: the Pearson correlation, and measures of amplitude and timing deviations. A high correspondence between the cardiac rhythms obtained via the ear-based and Lead I measurements is rigorously confirmed through agreement between simulation and measurement, while the real-world feasibility was conclusively demonstrated through efficacious cardiac rhythm monitoring during prolonged driving. This work opens new avenues for seamless, hearable-based cardiac monitoring that extends beyond heart rate detection to offer cardiac rhythm examination in the community.

Hearables: In-Ear Multimodal Data Fusion for Robust Heart Rate Estimation

“…Hearables are a very convenient wearables modality, owning the privileged position of the head and ear canal on the human body and the fixed distance to vital organs. However, the in-ear ECG [8] signal, measured between electrodes placed inside the ear canal, has a smaller amplitude that standard ECG acquired from torso and a lower signal-to-noise ratio, making it difficult to automatically detect R peaks with standard algorithms [9]. On the other hand, earpieces provide a good fit and benefit from collocated position of multiple sensors (electrodes, accelerometer, microphone, and photoplethysmography (PPG) sensor) on an earplug [10].…”