mHealth Research Digest by Tim Bredrup

Today’s smartphones are now equipped with cameras that can be used to detect changes in heart rate in a person’s finger using a technology called photoplethysmographic (PPG) measurement.

PPG refers to the technology commonly used by a pulse oximeter to capture blood volume change by illuminating the finger with a light-emitting diode.

When the light that is shining on the finger changes as a result of blood moving in and out of the finger, the change can be measured. Recently a team of researchers in South Carolina performed research to determine the validity of an Android-based software program to detect and capture heart rate measurements as a proof of concept for its use,  The software was compared them to traditional means of measuring heart rate (ECG and pulse oximeter).

A total of three devices were used in the study to gather heart rate measurements during various movement-free tasks.  They included a Motorola Droid, an electrocardiograph (ECG), and a Nonin 9560BT pulse oximeter.  As described in the study’s methods,heart rates “ were collected simultaneously from 14 subjects, ages 20 to 58, healthy or with clinical conditions, using the 3 devices during 5-minute periods while at rest, reading aloud under observation, and playing a video game.”

The results revealed high correlations between all device pairs and across all conditions.  Bland-Altman plots further revealed the Droid as being a valid way to measure heart rates. “Across all conditions, the Droid compared to ECG” the study declared.

Researchers concluded that the Android app provides valid heart rate readings at varying levels of movement.   Furthermore, components such as electrode patches and wireless sensor telemetric straps are not necessary, which makes the Droid app less complicated and more user friendly. However, additional research still needs to be done to determine how well this new medium can perform during physical movement-related activities.  In addition, further research is needed to determine if other smartphones and similar apps can meet the standards of validity as the Motorola Droid.

Authors: Gregoski MJ, Mueller M, Vertegel A, Shaporev A, Jackson BB, Frenzel RM, Sprehn SM, Treiber FA.

Institutions: South Carolina Center of Economic Excellence, Technology Applications Center for Healthful Lifestyles (TACHL), Medical University of South Carolina, Charleston, SC, USA.

Original Abstract: Pubmed