Affective Embodied Agent for Patient Assistance in Virtual Rehabilitation

This research presents an affective embodied agent to generate empathic interactions in an upper limb virtual rehabilitation platform, enhancing the platform's usability and encouraging its use at home without close supervision by physiotherapists. The agent interacts using natural language (Spanish) and simulating affective states through facial expressions and voice intonation. An interaction component set was defined by considering the opinions of several physiotherapists, including an affective state set (neutrality, enthusiasm, happiness, surprise) and a set of phrases to be expressed by the agent. A 3D model was designed and since affective state perception is subjective, its facial expressions were chosen through a consensus-based study. The agent's affective behavior was defined by a control model that receives the patient's affective state and performance as inputs. It is a rule-based system with averaging and synchronization techniques and a selection method based on probability distributions to provide more natural interactions. A usability evaluation was performed on both versions of the platform, with and without the agent, on a group of 12 non-disabled participants and another of 12 disabled. The results suggest that the agent provides empathic and motivating user experiences, enhances usability, and encourages the use of the platform at home without close expert supervision