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The Supernumerary Dorsal Grasper for people with C5-C7 spinal cord injury
  • +3
  • Jungpyo Lee,
  • Andrew I. W. Mcpherson,
  • Haoxiang Huang,
  • Licheng Yu,
  • Yuri Gloumakov,
  • Hannah S. Stuart
Jungpyo Lee

Corresponding Author:[email protected]

Author Profile
Andrew I. W. Mcpherson
Haoxiang Huang
Licheng Yu
Yuri Gloumakov
Hannah S. Stuart


Spinal cord injuries (SCI) substantially affect sensory, motor, and autonomous functions below the level of injury, reducing the independence and quality of life for affected individuals. Specifically, people with SCI between C5 and C7 cervical levels encounter limitations in voluntary finger and wrist flexion, reducing grasp capability. Compensatory strategies like tenodesis grasp, whereby wrist extension passively closes the fingers, remain; this is effective for lighter objects but insufficient for heavier ones. Typically, wearable assistive exoskeletons are designed to actuate a person's fingers, however, such devices are sensitive to anatomical variability, such as hand size and joint contractures. Addressing this challenge, here we present a new version of the Dorsal Grasper, a wearable device designed for those with voluntary wrist extension, providing human-robot collaborative grasping capabilities with underactuated supernumerary fingers on the back of the hand. We show that the Dorsal Grasper expands the graspable workspace and reduces trunk motion, especially in situations where the use of a wheelchair restricts the individual's posture. Our experiments with SCI participants demonstrate the Dorsal Grasper 's potential as a versatile assistive solution for enhancing grasping capability in individuals with distinct SCI profiles.
16 May 2024Submitted to TechRxiv
21 May 2024Published in TechRxiv