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Selected Publication:
SHR Neuro Cancer Cardio Lipid Metab Microb
Rafolt, D; Gallasch, E.
Influence of contact forces on wrist photoplethysmography--prestudy for a wearable patient monitor.
BIOMED TECH. 2004; 49(1-2): 22-26.
Doi: 10.1515/BMT.2004.005
Web of Science
PubMed
FullText
FullText_MUG
- Co-authors Med Uni Graz
- Gallasch Eugen
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- Abstract:
- The practical setting shows that gentle manual pressure on a photosensor suffices to improve the detectability of arterial pulses, but changes in the pressure applied may also produce signal artefacts. To study these effects, stepwise increasing contact forces (0.5 to 4 N) were applied to a photosensor placed over the radial artery. Additionally, the influence of optical coupling between sensor and skin surface was examined by introducing an elastic distance ring. The AC and DC components from the recorded photoplethysmogram were analysed. The AC component (absorption due to arterial pulsation) increased with the pressure applied; at lower forces (0.5 to 3 N) an introduction of the ring enhanced this effect. The characteristic of the DC component (backscattering from non-pulsating tissues) depends on optical coupling: without the ring the DC component increased stepwise with force (slope 0.035 V/N), but with the ring in place this component decreased (slope -0.075 V/N). Since the sensitivity of the pulse signal to artifacts is related to the slope of the DC component, such artefacts can be minimized by making the slope small. The utilization of these results to improve pulse detection and reduce motion artefacts in a wearable wrist device is discussed.
- Find related publications in this database (using NLM MeSH Indexing)
- Equipment Design -
- Heart Rate -
- Humans -
- Monitoring, Physiologic - instrumentation
- Motor Activity - instrumentation
- Paraplegia - rehabilitation
- Photoplethysmography - instrumentation
- Pulse - instrumentation
- Radial Artery - instrumentation
- Signal Processing, Computer-Assisted - instrumentation
- Wrist - blood supply
- Find related publications in this database (Keywords)
- PPG
- pulse detection
- radial artery
- opto-mechanical coupling
- wrist device
- movement artifacts