iPhysioMeter: a new approach for measuring heart rate and normalized pulse volume using only a smartphone

Area of Science:

• Psychophysiology
• Biomedical Engineering
• Mobile Health

Background:

• Heart rate (HR) and normalized pulse volume (NPV) are crucial physiological indices in psychological research.
• Traditional measurement methods for HR and NPV are often time-consuming and require specialized laboratory equipment.

Purpose of the Study:

• To develop and validate a novel smartphone application, iPhysioMeter, for accurate beat-by-beat measurement of HR and ln NPV.
• To assess the usability of iPhysioMeter compared to conventional laboratory measures.

Main Methods:

• Development of the iPhysioMeter smartphone application for physiological data acquisition.
• Recruitment of 12 participants to undergo mental stress tasks designed to modulate HR and ln NPV.
• Application of Bland-Altman analysis to compare iPhysioMeter measurements against gold-standard laboratory techniques.

Main Results:

• iPhysioMeter demonstrated negligible proportional bias for both absolute HR, ln NPV, and their change values (ΔHR, Δln NPV).
• A small fixed bias was observed for ln NPV and Δln NPV, but these remained within acceptable limits of agreement.
• The app showed high accuracy for measuring the absolute level of HR and relative changes in ln NPV.

Conclusions:

• The iPhysioMeter application provides a valid and accessible tool for measuring beat-by-beat HR and relative changes in ln NPV.
• This smartphone-based approach offers a practical solution for researchers needing to measure key physiological indices outside of traditional lab settings.
• iPhysioMeter has the potential to broaden the scope and accessibility of psychophysiological research.