IDEA-FAST trial: Smartphone interaction tracks fatigue in 137 patients across 6 diseases

Assessing fatigue, sleep disturbances, and activity changes in neurodegenerative diseases (NDD) and immune-mediated inflammatory diseases (IMID) typically relies on patient-reported outcomes (PROs) from standardized questionnaires filled out every few months. This method is plagued by subjectivity, low sensitivity to change, and an inability to capture day-to-day variability. A new study from the IDEA-FAST Consortium, led by Julian Fierrez and colleagues at COMPSAC 2026, proposes using smartphone interaction data as a proxy for these symptoms. The team analyzed screen-time and app-usage patterns from 137 participants spanning 6 different disease groups plus a healthy control group, tracking how patients physically interact with their devices as a passive, objective measure of their condition.

The researchers applied repeated measures correlation to statistically link these device interaction features with PRO scores collected via a dedicated smartphone app. The results show meaningful correlations, indicating that subtle changes in smartphone behavior—such as reduced usage, atypical timing, or altered app preferences—can reflect underlying fatigue, sleep problems, and reduced activity. This proof-of-concept demonstrates that mobile telemetry could complement or partially replace infrequent, subjective questionnaires, enabling continuous remote monitoring in clinical trials and real-world patient care. By capturing symptom fluctuations in near real-time, the approach may improve trial sensitivity, personalize treatment adjustments, and reduce patient burden—though further validation in larger cohorts is needed before clinical deployment.