Smartphone-Based Passive Sensing of Activity Levels and Behavioral Activation During Psychosocial Interventions for Older Adults With Depression: Longitudinal Observational Study

Background

A key symptom of depression is reduced behavioral activation, namely, low activity levels and reduced meaningful engagement with the external environment. Thus, objective and timely measures of activity levels are useful tools to precisely track individuals' activity levels during treatment. Prior adult depression studies have shown that activity levels measured using passive sensing (eg, step counts and time spent away from home) predict depression relapse, persistence, and poor response to psychosocial interventions. However, there is scarce research on how passive sensing measures relate to behavioral activation, especially in late-life depression.