A Digital Assistive System for Maintaining Nutrition and Mobility in Older Adults: Usability and Feasibility Findings From a Pilot Study

Background: Due to demographic changes, the number of older people is increasing, often accompanied by limitations in mobility, nutrition, and independence. Preventive monitoring is rare, as care systems struggle with staff shortages and limited resources. Technical assistance systems can support older people in self-assessing their health and maintaining independence. We developed the AS-Tra system, which combines an application with a measurement and training station (MuTS), to enable early detection of nutrition and mobility-related deficits and risks. Objective: This paper presents the pilot study of the AS-Tra system with the aim of evaluating its usability and testing the feasibility of collecting health-related data from older adults (≥70 y) with early/mild deficiencies in nutritional state and mobility in preparation for a future randomized controlled trial. Methods: The system used in this 4-week pilot study was developed as a complex intervention in accordance with the Medical Research Council framework. Participants (target n=10) were recruited through a participant registry. They completed standardized mobility assessments (grip strength, Timed "Up and Go," and 5-Time Chair Rise) at baseline and after 1, 2, and 4 weeks (T0, T1, and T2, respectively). Mini Nutritional Assessment-Short Form and short physical performance battery were recorded at baseline and at T2. Participants received a tablet app for regularly documenting nutrition and an activity sensor for 7 days of physical activity monitoring and performed weekly training starting at T0. At T2, the System Usability Scale (SUS) and feedback questionnaires (Evaluation Overall System [EOS] questionnaire-the evaluation of all subcomponents on a scale of 1-5, weekly Experience Report) were additionally collected. Data were analyzed descriptively using IBM SPSS Statistics, in which data were shown as total numbers, percentages, and means with SDs, and data from the activity sensor were displayed and analyzed using Python. Results: A total of 9 older adults, with 1 dropout (mean 80, SD 5 y, 50% female), participated in this study. The SUS score was good (mean 79, SD 13.4 points). The MuTS devices had minor technical problems (in <17% of MuTS sessions), while 57% (17/30) of the users experienced instability issues with the food diary in the tablet app. The average overall system ratings were positive, with an EOS score of 2.01 (SD 0.99). Conclusions: The usability of the technical assistance system used in this study was rated as good. The data collection using questionnaires, sensors, and automated assessments proved feasible. The biggest challenge was the tablet-based food diary, which still needs improvement before the effectiveness of the AS-Tra system regarding mobility and nutritional status can be evaluated in a randomized controlled trial.