Advancing mobile health interventions

Technology has created unprecedented opportunities to increase the reach and impact of healthcare with digital interventions. Digital technologies can also collect rich and granular data about a person’s state and context and leverage this information to adapt interventions to the rapidly changing needs of individuals in real-time, in their daily lives.

Despite the increasing use and appeal of digital interventions, a major gap exists between the growing technological capabilities for delivering them and research on the development and evaluation of these interventions.

Our team is developing new intervention frameworks and experimental designs that help investigators leverage advanced digital technologies to construct powerful interventions.

Just-in-Time Adaptive Interventions

A Just-in-Time Adaptive Intervention (JITAI) is a digital intervention delivery framework that guides how rapidly changing information about the person’s state and context should be used in practice to decide whether and how to intervene in real-time, in everyday life. JITAIs typically guide the adaptation of digital components on relatively fast timescales, typically every few days, hours or minutes.

EXAMPLE. A JITAI decision rule protocolizes an intervention for cigarette smoking. Learn more about this JITAI.
  • JITAIs address conditions that represent vulnerability to an adverse proximal outcome and/or conditions that represent an opportunity to promote a desired proximal outcome.
  • JITAIs avoid delivering an intervention when it is unnecessary or potentially harmful. Interventions are delivered only when needed, that is, only when states of vulnerability or opportunity occur.
  • JITAIs only deliver an intervention when an individual is receptive to the intervention. Receptivity is defined as the conditions in which the individual is likely to effectively engage with the intervention under consideration.

Micro-Randomized Trials for Optimizing JITAIs

When developing a Just-in-Time Adaptive Intervention, investigators often have scientific questions about how to best deliver and adapt momentary interventions in the real world. A Micro-Randomized Trial (MRT) helps investigators answer these questions. The MRT is a randomized trial that includes rapid sequential randomizations. This means that the same person may be repeatedly randomized to intervention options hundreds or thousands of times during a trial.

MRTs answer questions about how to intervene.

Is it beneficial* to deliver vs. not deliver a daily prompt?

*In terms of a pre-specified proximal outcome

MRTs answer questions about when to intervene.

Under what conditions is it most beneficial to deliver the prompt?

MRTs answer questions about how to adapt treatment.

Does the effect of the prompt dissipate with time?

EXAMPLE. In the mobile assistance for regulating smoking (MARS) micro-randomized trial, a survey is delivered six times per day. Following the survey, participants are randomized to one of three intervention options. Learn more about MARS.
EXAMPLE. In the mobile assistance for regulating smoking (MARS) micro-randomized trial, a survey is delivered six times per day. Following the survey, participants are randomized to one of three intervention options. Learn more about MARS.

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Featured Resources

Carpenter, S. M., Menictas, M., Nahum-Shani, I., Wetter, D. W., & Murphy, S. A. Developments in Mobile Health Just-in-Time Adaptive Interventions for Addiction Science. Curr Addict Rep 7, 280–290 (2020).

Hiremath, S. V., Amiri, A. M., Thapa-Chhetry, B., Snethen, G., Schmidt-Read, M., Ramos-Lamboy, M., . . . Intille, S. S. (2019). Mobile health-based physical activity intervention for individuals with spinal cord injury in the community: A pilot study. PloS one, 14(10), e0223762.

Nahum-Shani, I., Potter, L. N., Lam, C. Y., Yap, J., Moreno, A., Stoffel, R., Wu, Z., Wan, N., Dempsey, W., Kumar, S., Ertin, E., Murphy, S. A., Rehg, J. M., & Wetter, D. W. (2021). The mobile assistance for regulating smoking (MARS) micro-randomized trial design protocol. Contemporary clinical trials, 110, 106513.

Nahum-Shani, I., Hekler, E. B., & Spruijt-Metz, D. (2015). Building health behavior models to guide the development of just-in-time adaptive interventions: A pragmatic framework. Health Psychology, 34(S), 1209.

Nahum-Shani, I., Smith, S. N., Spring, B. J., Collins, L. M., Witkiewitz, K., Tewari, A., & Murphy, S. A. (2018). Just-in-Time Adaptive Interventions (JITAIs) in Mobile Health: Key Components and Design Principles for Ongoing Health Behavior Support. Annals of behavioral medicine : a publication of the Society of Behavioral Medicine, 52(6), 446–462.

Walton, A., Nahum-Shani, I., Crosby, L., Klasnja, P., & Murphy, S. (2018). Optimizing Digital Integrated Care via Micro-Randomized Trials. Clinical pharmacology and therapeutics, 104(1), 53–58.

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