The Principles of Hearable Photoplethysmography Analysis and Applications in Physiological Monitoring–A Review
Level 5 - mechanism / opinion, no new human data
Integrative literature review of technical configurations and engineering studies without meta-analysis or clinical trial synthesis
OpenAlex W4384826601 · doi:10.3390/s23146484
What was done
Authors conducted an integrative literature search across IEEE, ScienceDirect, Scopus, Web of Science, and PubMed up to December 2022 to evaluate in-ear photoplethysmography (PPG) technology. The review evaluated PPG measurement principles, sensor configurations, waveform characteristics, and signal processing/feature extraction methods for physiological monitoring.
What was found
The search initially identified 14 studies, of which 9 were finalized for review. Eight studies focused on principles and sensor configurations, and eight addressed signal processing technology and feature extraction. The abstract reports no quantitative performance metrics, accuracy statistics, or effect estimates.
Why it matters
This review synthesizes the technical feasibility of using earbud-based PPG sensors to capture vital signs beyond oxygen saturation, such as pulse rate, respiration rate, and blood pressure, while outlining engineering hurdles.
Limits
The review synthesizes a very small body of evidence (only 9 included studies). The abstract provides no quantitative data, quality assessment, or evaluation of specific human clinical populations.
Cited by
- supports A sensor placed in the ear concha can measure heart rate, pulse, blood oxygen levels, electrooculogram (EOG) eye movement signatures, and EEG signatures related to attention.