Background: Neurological injuries, such as stroke, often lead to motor and somatosensory impairments of the hand. Deficits in somatosensation, especially proprioception, result in difficulties performing activities of daily living involving fine motor tasks. As those impairments are challenging to accurately evaluate and monitor, therapies rarely focus on proprioception specifically, even though it has been shown that such training could promote functional benefits. In this work we propose and preliminarily evaluate the feasibility, usability and effectiveness of a robot-assisted therapy focused on finger proprioception.
Methods: We designed and implemented on an existing robotic platform (ETHMIKE) five therapeutic exercises, focusing on finger somatosensation, two targeting passive and three active position sense. The difficulty level of the therapy exercises was automatically adapted to each patient’s proprioceptive impairment, assessed using the same platform (i.e., assessment-driven therapy). Nine subacute stroke participants completed the robotic therapy for at least two weeks, 30 minutes per day, five times a week. Data was compared to a control group based on a previously collected dataset where subacute stroke participants received usual care and the same assessments.
Results: We found that the proposed exercises were feasible for stroke participants, as everyone managed to progress in difficulty levels. Moreover, the exercise performance averaged between 59% and 70% of maximum possible performance for the different exercises, indicating adequacy of the difficulty adaptation algorithm and a balance between motivation and challenge. Further, usability was rated as acceptable, as NASA Task Load Index (raw TLX), which provides an overall workload score, was mostly below 50%, except for mentaldemand. There was a significant improvement in proprioceptive error and in the Box and Block Test score from study inclusion to discharge for the intervention group, which was not the case for the control group.
Conclusions: This work demonstrated the first insights into feasibility, usability and effectiveness of a novel robot-assisted therapeutic approach. These encouraging results pave the way for further development and validation of therapy approaches focusing on somatosensory function.