Substitutive proprioception feedback of a prosthetic wrist by electrotactile stimulation

Yichen Han; Yinping Lu; Yufeng Zuo; Hongliang Song; Chih-Hong Chou; Xing Wang; Xiangxin Li; Lei Li; Chuanxin M Niu; Wensheng Hou

doi:10.3389/fnins.2023.1135687

Substitutive proprioception feedback of a prosthetic wrist by electrotactile stimulation

Front Neurosci. 2023 Feb 21:17:1135687. doi: 10.3389/fnins.2023.1135687. eCollection 2023.

Authors

Yichen Han¹, Yinping Lu¹, Yufeng Zuo¹, Hongliang Song¹, Chih-Hong Chou², Xing Wang¹, Xiangxin Li³, Lei Li⁴, Chuanxin M Niu⁵, Wensheng Hou¹

Affiliations

¹ Biomedical Engineering Department, Bioengineering College, Chongqing University, Chongqing, China.
² Laboratory of Neurorehabilitation Engineering, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
³ Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences (CAS), Shenzhen, Guangdong, China.
⁴ Department of Rehabilitation, Southwest Hospital, Army Medical University, Chongqing, China.
⁵ Department of Rehabilitation Medicine, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.

Abstract

Objective: Sensory feedback of upper-limb prostheses is widely desired and studied. As important components of proprioception, position, and movement feedback help users to control prostheses better. Among various feedback methods, electrotactile stimulation is a potential method for coding proprioceptive information of a prosthesis. This study was motivated by the need for proprioception information for a prosthetic wrist. The flexion-extension (FE) position and movement information of the prosthetic wrist are transmitted back to the human body through multichannel electrotactile stimulation.

Approach: We developed an electrotactile scheme to encode the FE position and movement of the prosthetic wrist and designed an integrated experimental platform. A preliminary experiment on the sensory threshold and discomfort threshold was performed. Then, two proprioceptive feedback experiments were performed: a position sense experiment (Exp 1) and a movement sense experiment (Exp 2). Each experiment included a learning session and a test session. The success rate (SR) and discrimination reaction time (DRT) were analyzed to evaluate the recognition effect. The acceptance of the electrotactile scheme was evaluated by a questionnaire.

Main results: Our results showed that the average position SRs of five able-bodied subjects, amputee 1, and amputee 2 were 83.78, 97.78, and 84.44%, respectively. The average movement SR, and the direction and range SR of wrist movement in five able-bodied subjects were 76.25, 96.67%, respectively. Amputee 1 and amputee 2 had movement SRs of 87.78 and 90.00% and direction and range SRs of 64.58 and 77.08%, respectively. The average DRT of five able-bodied subjects was less than 1.5 s and that of amputees was less than 3.5 s.

Conclusion: The results indicate that after a short period of learning, the subjects can sense the position and movement of wrist FE. The proposed substitutive scheme has the potential for amputees to sense a prosthetic wrist, thus enhancing the human-machine interaction.

Keywords: electrotactile stimulation; proprioceptive feedback; prosthetic wrist; sensory substitution; transradial amputee.

Grants and funding

This research was supported by the National Key Research and Development Program of China (2020YFC2007900), the National Natural Science Foundation of China (NSFC31771069), and the Key-Area Research and Development Program of Guangdong Province (2020B0909020004).