iPhysioMeter: A Smartphone Photoplethysmograph for Measuring Various Physiological Indices

Abstract

iPhysioMeter is a new smartphone application ("App") for the Apple iPhone and iPod touch that allows photoplethysmography (PPG) to be implemented without the need for any additional devices. The resulting signal, the photoplethysmogram, allows the calculation of basic but valuable and frequently used physiological indices such as heart rate (HR) and pulse volume (PV). The design of iPhysioMeter has very much been influenced by a consideration of usability, as is immediately evident from ones first experience with it. However, its apparent simplicity in use should not disguise the need for correct operation, which otherwise might lead to collection of invalid or inaccurate data. There are several unexpected pitfalls that might not only produce inaccurate values, but, under some circumstances, could also damage the device or present a hazard to the user or subject. We therefore describe here, firstly, the core technology that makes it possible to perform PPG and to calculate HR and normalized PV (NPV) from the photoplethysmogram using only a smartphone, secondly, the correct and optimum methods and procedures for using iPhysioMeter that will help to ensure safety and the derivation of valid data under real operational conditions. We hope that these descriptions will help facilitate any activities related to physiological measurement when using only a smartphone.

Cuffless blood pressure estimation using only a smartphone

“…Three data points from the iPhone 6s smartphone were treated as missing values according to the iPhysioMeter SM ’s built-in algorithm detecting outliers 34 . One data point from the dedicated photoplethysmograph could not be analysed because of an intense artefact, and was removed.…”

Literature Review of the Usefulness of Smartphone for the Evaluation and Treatment of Mental Disorders

“…When Peng et al [32] evaluated frequency-domain and nonlinear parameters, the parameters of HRV, among 30 normal participants using photoplethysmographs of smartphones, the results showed a significantly high correlation with laboratory ECG results. Matsumura et al [33] measured beat-by-beat HR and normal pulse volume via smartphone using the iPhysioMeter app among 12 participants, and compared the results to that of conventional laboratory measures; the comparison showed the iPhysioMeter app to be very effective in evaluating absolute levels of heart rate and relative changes in normal pulse volume. Unfortunately, few studies have evaluated mental symptoms by analyzing HRV through smartphones.…”

Reliability of heart rate mobile apps in young healthy adults: exploratory study and research directions

“…The first implementation on smartphone, using its camera and flash, has been described by Pelegris et al 2; however, a number of mobile applications are nowadays available, some of which are also described in scientific literature 3 , 4…”