1. Kevin Patrick, MD, MS Center for Wireless and Population Health Systems, University of California, San Diego, La Jolla, California
NSF International Workshop on Dynamic Modeling of Health Behavior Change and Maintenance,
Sept 8-9, 2015, London, UK
MH2010 | K. Patrick

2. 1. Sensors are available to capture continuous data on:
Assumptions:
1. Sensors are available to capture continuous data on:
Physical Activity
Sedentary periods
Location
Heart rate
2. The platform for intervention will be based around a
mobile phone, one or more wearable sensors and
computational elements on the sensors, phone and
in the cloud.
NSF International Workshop on Dynamic Modeling of Health Behavior Change and Maintenance,
Sept 8-9, 2015, London, UK

3. Assumptions (cont):
3. Prior to the onset of the intervention we can gather
baseline information on:
Strategies for weight management
Location of residence, workplace,
usual transportation practices
Preferences for type(s) of physical activity
(walking, cycling, gym, outdoors, etc.)
GIS and other location information on a rich set of
environmental influences on food intake such as locations
of healthy food, junk food, convenience stores,
locations where food identified by Skyler as problematic
may be found (e.g., bars where too much drinking and
snack consumption occurs).

4. Major influences
on health

5. Assumptions (cont):
4. We will have a run-in period of use of the system
in which background norms for Skyler can be ascertained.
At least a week, longer if possible, in particular if things
are changing at a longer term scale like new job,
move of residence, etc.

6. Describe the JITAI that you would like to develop.
Monitor physical activity as a proxy for calorie consumption.
Improve the modeling of this monitoring location data
and sending periodic SMS or other EMA strategies
to label and strengthen knowledge about times when
less than optimal food intake occurs
The intervention would then be based upon a combination
of energy expenditure data and location data, the latter
serving as a proxy for places where healthy or unhealthy
eating behaviors might occur – including at home & work.
Periodic prompts to improve labeling of selected events would
be provided to strengthen, over time, the expert aspects
of the intervention.

7. What framework would you need to enable decisions
on what, when, how and where, to provide
that momentary intervention?
It would be a combination of time-based messages
(based upon a priori specified “at risk” times for either
good or bad SWMs) and prompted assessments (pulls)
or messages (pushes) based upon other key elements.
Could also factor in the types of messages that are liked or
not liked.

8. What theory would you employ, and how?
Behavior change techniques would be used, as would
control theory.
Measure, feedback, measure again, feedback, etc.,
based upon results, preferences, etc.

9. Where do you think that theory might break down in
the context of momentary interventions that can
be adapted to individual needs on the fly
(Just-In-Time, Adaptive Interventions, or JITAIs;
Ecological momentary interventions)?
It might break down during times of unusual stress or
other external issues that are not under the control of Skyler.

10. For how long a period of time would you need to
collect those data before willfully perturbing that
data by initiating an intervention?
It depends… A few days for some of the training data.
But this might depend upon how robust the
classification method is as well as on how many different
data sources are being used for the intervention
elements.

11. ConTxt Sketch the framework… PURPOSE
To develop and test the efficacy of a SMS intervention for weight loss among overweight and moderately obese (BMI ) men and women ages 21–60. 
The ConTxt study builds upon our work with pilot SMS weight loss study mDIET.
The ConTxt study aims to extend the expert logic of the SMS messages including ecological components and evaluate it in an RCT.
NIH/NCI R01 CA138730; Patrick, PI
Copyright, Regents of the University of California, 2014

12. RCT Study Design Sketch the framework… n = 103 n = 103
RCT ENROLLMENT:
Began: October 2011
Completed: March, 2014
Community Recruitment: listservs, flyers, community events, print and/or radio advertisements
309 Subjects, years old male & female,
Weight: 27 < BMI < 39.9
English & Spanish speaking
Text Messages Users (or willing to learn)
n = 103
SMS Only
SMS Only + Counseling
n = 103
Comparison
Copyright, Regents of the University of California, 2014

13. SMS Logic & Flow Sketch the framework… Weekly Mastery
Assessment (Friday)
Sunday
Weekly SWM Messages
Willingness
Send SMS: “Are you willing to set goals for [WBI] this week? (y/n)”
Send SMS:
“On a scale of 1 (never) to 5 (always), how often did you [insert WBI] in the past week?”
Barrier SMS Messages
(M, T, W, TH, SA)
Mastery = Weekly Average (after 3 weeks) >/= to 4 NO
YES
Answer
1, 2, or 3
Answer
4 or 5
Knowledge Text Messages
Skills/ Tips Text Messages
Send Multiple Choice Barrier Question
Barrier 1
Barrier 2
Barrier 3
Barrier 4
SWM Maintenance Messages
(M, T, W, TH, SA)
Copyright, Regents of the University of California, 2014

14. “Liked” and “Unliked” Message Logic
Sketch the framework…
“Liked” and “Unliked” Message Logic
Copyright, Regents of the University of California, 2014