Leveraging human–robot interaction and virtual reality for digital biomarkers in diagnostics and rehabilitation: a review from the Age-It Research Program

Objectives: Digital biomarkers are indicators of physiological and behavioral processes, collected from digital devices that are useful for cognitive and physical assessment in older adults. This study focuses on identifying digital biomarkers emerging during robotic and virtual reality (VR)-based diagnostics and rehabilitation. It presents findings from a systematic review conducted within the activities of Spoke 9 (Advanced Gerontechnologies for Active and Healthy Ageing) of the Age-It Research Program. Methods: A literature review examined studies on digital biomarkers in relation to the technologies of interest, focusing on aging, up to March 25, 2025. Four hundred seventy-one English-written papers were retrieved; after screening, 19 studies were included. We summarized them considering the application domain, identifying the corresponding digital biomarkers, the target users, and the technology used. Results: For cognitive assessment, digital biomarkers are used to monitor patient behaviors during clinical tasks that use VR-based technologies and social robots. In VR-based cognitive rehabilitation scenarios, digital biomarkers are used to assess the performance of task accomplishment. In the physical activity monitoring domain, gait-related parameters are assessed by social robots, while thermal cameras are used for thermodynamic analyses. In the physical rehabilitation domain, digital biomarkers related to the upper-body motions are usually considered. Discussion: Despite promising results, several improvements are needed. Robotic solutions offer versatility in terms of applications but have low readiness. Similarly, thermodynamic models require strict conditions for reliability. Virtual reality-based cognitive assessment lacks temporal data for better discrimination, and VR-based cognitive rehabilitation is limited by a lack of multimodal stimulation. Future research should address these limitations effectively.