Mechanism evaluation of a digitally enabled rehabilitation intervention for people in aged care and neurological rehabilitation: mediation analysis of the AMOUNT trial

To investigate potential mechanisms of a digital rehabilitation intervention associated with improved mobility among adults undertaking rehabilitation. Causal mediation analysis of the AMOUNT trial (ACTRN12614000936628). Participants were randomised to digitally-enabled rehabilitation (virtual reality video games, activity monitors, and handheld computer devices prescribed by a physiotherapist) and usual care or usual care alone. Outcomes were mobility (Short Physical Performance Battery; continuous version; range 0–3), physical activity (average steps per day), and quality of life (EQ-5D-5L; utility score; range 0–1) measured at 6-months post-randomisation. Hypothesised mediators included mobility, physical activity, cognition, balance confidence, pain, activity and participation, and computer self-efficacy, assessed at 3-weeks post-randomisation. 216 participants with complete data were included. Three-week sit-to-stand ability mediated 6-month mobility (indirect effect 0.09 points, 95%CI 0.03–0.16), explaining 48% of the intervention’s effect. Dynamic single-leg-stance balance mediated physical activity (indirect effect 345 steps per day, 95%CI 63–678) and composite mobility mediated quality of life (indirect effect 0.03 points, 95%CI 0.00–0.05). Digital rehabilitation outcomes appear to be mediated through sit-to-stand ability, dynamic single-leg-stance balance, and overall mobility. While future research is required to better understand these mediators, our findings recommend sit-to-stand training as a core element of digital rehabilitation interventions targeting mobility. Digital interventions are one option for people undergoing rehabilitation to achieve more task-specific practice in the hospital and home setting.Digital interventions aimed at improving mobility should include repetitive sit-to-stand practice, as sit-to-stand ability is a key driver of improved mobility.Digital interventions aimed at improving physical activity should include exercises that target dynamic balance, however this requires further research.Improving overall mobility should remain a key focus of using digital interventions in rehabilitation as this is a potentially important driver for improving quality of life, however this requires further research. Digital interventions are one option for people undergoing rehabilitation to achieve more task-specific practice in the hospital and home setting. Digital interventions aimed at improving mobility should include repetitive sit-to-stand practice, as sit-to-stand ability is a key driver of improved mobility. Digital interventions aimed at improving physical activity should include exercises that target dynamic balance, however this requires further research. Improving overall mobility should remain a key focus of using digital interventions in rehabilitation as this is a potentially important driver for improving quality of life, however this requires further research.