Robotics-Assisted Mirror Rehabilitation Therapy A Therapist-in-the-Loop Assist-as-Needed Architecture
This paper presents a Therapist-in-the-Loop (TIL) framework for robotics-assisted mirror rehabilitation integrated with adaptive Assist-as-Needed Therapy (ANT) that is adjusted based on the impairment and disability level of the patient’s affected limb. The framework which is designed for patients with hemiparesis and/or hemispatial neglect, uses a Patient’s Functional Limb (PFL) as the medium to transfer therapeutic training from the therapist to the Patient’s Impaired Limb (PIL). This allows the patient to use his/her functional limb to adjust the desired trajectory generated by the therapist if the trajectory is painful or uncomfortable for the PIL. In order to realize the adaptive patient-targeted therapy, two motor-function assessment metrics, Performance Symmetry and Level Of Guidance are proposed, providing real-time, task-independent and objective assessment of the PIL’s motor deficiency. An adaptation law is also presented to adjust the intensity of the therapy delivered to the patient in real-time and based on the aforementioned estimation of the impairment level of the PIL. Closed-loop system stability has been investigated in the presence of communication delays to facilitate tele / in-home rehabilitation. For this purpose, a combination of the Circle Criterion and the Small-Gain Theorem has been applied to account both for communication time delays and the time-varying adaptive assist-as-needed training. Results of experiments to investigate the performance of the proposed framework are reported.