Format

Send to

Choose Destination
J Med Internet Res. 2016 Jun 1;18(6):e106. doi: 10.2196/jmir.5398.

Feasibility and Performance Test of a Real-Time Sensor-Informed Context-Sensitive Ecological Momentary Assessment to Capture Physical Activity.

Author information

1
Department of Preventive Medicine, University of Southern California, Los Angeles, CA, United States. dunton@usc.edu.

Abstract

BACKGROUND:

Objective physical activity monitors (eg, accelerometers) have high rates of nonwear and do not provide contextual information about behavior.

OBJECTIVE:

This study tested performance and value of a mobile phone app that combined objective and real-time self-report methods to measure physical activity using sensor-informed context-sensitive ecological momentary assessment (CS-EMA).

METHODS:

The app was programmed to prompt CS-EMA surveys immediately after 3 types of events detected by the mobile phone's built-in motion sensor: (1) Activity (ie, mobile phone movement), (2) No-Activity (ie, mobile phone nonmovement), and (3) No-Data (ie, mobile phone or app powered off). In addition, the app triggered random (ie, signal-contingent) ecological momentary assessment (R-EMA) prompts (up to 7 per day). A sample of 39 ethnically diverse high school students in the United States (aged 14-18, 54% female) tested the app over 14 continuous days during nonschool time. Both CS-EMA and R-EMA prompts assessed activity type (eg, reading or doing homework, eating or drinking, sports or exercising) and contextual characteristics of the activity (eg, location, social company, purpose). Activity was also measured with a waist-worn Actigraph accelerometer.

RESULTS:

The average CS-EMA + R-EMA prompt compliance and survey completion rates were 80.5% and 98.5%, respectively. More moderate-to-vigorous intensity physical activity was recorded by the waist-worn accelerometer in the 30 minutes before CS-EMA activity prompts (M=5.84 minutes) than CS-EMA No-Activity (M=1.11 minutes) and CS-EMA No-Data (M=0.76 minute) prompts (P's<.001). Participants were almost 5 times as likely to report going somewhere (ie, active or motorized transit) in the 30 minutes before CS-EMA Activity than R-EMA prompts (odds ratio=4.91, 95% confidence interval=2.16-11.12).

CONCLUSIONS:

Mobile phone apps using motion sensor-informed CS-EMA are acceptable among high school students and may be used to augment objective physical activity data collected from traditional waist-worn accelerometers.

KEYWORDS:

accelerometer; ecological momentary assessment; mobile phones; physical activity

PMID:
27251313
PMCID:
PMC4909979
DOI:
10.2196/jmir.5398
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for JMIR Publications Icon for PubMed Central
Loading ...
Support Center