HeartSteps

SARA

Bari-Fit

Sense2Stop

JOOLHEALTH

Brief Introduction to

Micro-Randomized Trials

Susan A Murphy

Goal: Develop mobile intervention for individuals who are trying to quit smoking • We know that stress predicts

lapse/relapse • We know that conducting stress-

management exercises can be effective for reducing stress.

• → Stress is a natural intervention target

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o Wrist/chest bands provide physiological sensor streams, used by an algorithm to provide minute level stress classifications

o Self-report provides craving, burden,…..

o Stress-management exercises available on smartphone 24/7 3

Mobile Health Interventions Two broad classes of intervention components: pull and push

– Stress-management apps, accessible 24/7 on mobile device, are pulls.

Pull components are great – Allow inclusion of many components – Put user in control of access – Low burden

But… Pull components require user to recognize when they need

help and remember to access the support

Mobile Health Interventions Push components

– Reminders to access the stress-management apps are pushes

Push components hold much potential – Can use sensing and user modeling to determine right

delivery time – Don’t rely on user’s awareness of times of need or

remembering to access But…

– High burden Motivates optimizing the mobile health intervention

prior to evaluation

Some Questions to Optimize Sense2Stop

• Do the reminders to use the stress management exercises have an effect on subsequent stress at all?

• Does the effect of the reminders change over time? (e.g., do people habituate to the reminders and become less responsive with time?)

• When should we send the reminders for optimal effect? – When individuals are stressed or not-stressed?

• Is current stress a tailoring variable?

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• Each participant may be randomized 100’s or 1000’s of times.

• Sense2Stop: randomized between (1) provide a reminder to access self-management apps and (2) do nothing.

• MRTs provide data to construct and optimize a mobile intervention involving pushes

• These trials are not useful for evaluating a mobile health intervention!

What is a Micro-Randomized Trial?

Micro-Randomized Trial Elements

1. Outcomes: 1. Distal: Time to relapse 2. Proximal: Stress episode in next 2 hours

2. Contextual data: sensor & self-report data 3. Times at which a push might occur

1. Decision points: Every minute in Sense2Stop 4. Randomize among options at decision point

1. reminder vs no reminder 8

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Sense2Stop

PI: S Kumar Location: Northwestern University, B. Spring, (P.I.) Funding: NIBIB through funds provided by the trans-NIH Big Data to Knowledge initiative U54EB020404

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Micro-Randomized Trials: When are they (not) useful?

• NOT USEFUL: When malleable circumstances are rare: Want to learn the best type of alert to prevent suicide attempt

• USEFUL: When malleable circumstances change rapidly: Stress, urges to smoke, adherence, physical activity, eating

• NOT USEFUL: Proximal outcome cannot be feasibly assessed.

• USEFUL: Proximal outcome can be unobtrusively sensed or unobtrusively self-reported.

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Collaborators!

EXTRA SLIDES

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Data • Autosense cheststrap &

wristband passively sense respiration, ECG, accelerometry, 6-axis inertial sensing

• cStress classifies every minute as Stress / Not Stress / Unclear, (validated in lab and in real life)

– Random & event contingent self-reports for smoking, mood, context

– $ microincentives for sensor wear, rapid responding, session attendance

Intervention Push is a Reminder to Access Stress Management Apps:

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Apps employ • Evidence-based exercises to manage stress • Take about 3-5 minutes to practice • Developed and refined based on input

from experts and users

Mood Surfing: - 3 exercises - Grounded in ACT - Target cognitive defusion - Experts: K. Witkiewitz, I. Yovel. - Literacy level editor: A. Applegate - HCI: M. Sharmin; Programmer: M. Hossain

Thought Shakeup - Grounded in CBT - Target cognitive restructuring - Expert: I. Yovel. - Literacy level editor: A. Applegate - HCI: M. Sharmin; Programmer: M. Hossain

Head Space - Grounded in ACT - Mediation / Mindfulness - Consistently rated as one of the best 5

commercial mediation apps - Permission for free use in the trial

The Micro-Randomization

– Randomization to intervention or no intervention could happen every minute, BUT no randomization occurs under conditions of “UNAVAILABILITY:”

1. Can’t provide a stress classification: stress level unclear; physically active; poor data (UNCERTAINTY)

2. Person driving (SAFETY) 3. < 60 minutes since last intervention; < 10 minutes since EMA

(BURDEN)

– Micro-randomization probabilities set to yield: • average of 3 interventions/day across morning, afternoon,

evening w/50% under Stress, 50% under No Stress

Micro-Randomized Trial Elements 1. Record outcomes

– Distal (time to relapse) & Proximal Outcome (stress episode in next 2 hours)

2. Record sensor & self-report data 3. Randomize among intervention options at decision points (reminder vs no reminder) 4. Use data after study ends to assess if it is useful to include the push, and if so, when it is best to deliver the push intervention 16