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OrthoHand Extend: Design, Modeling and Evaluation of a Simple Wrist-Hand Stretching Orthosis for Neurologically Impaired Patients
  • Elissa Ledoux,
  • Nithin S Kumar
Elissa Ledoux

Corresponding Author:[email protected]

Author Profile
Nithin S Kumar


To better understand the upper-limb needs and challenges survivors of neurological events face, and the issues associated with existing technology, customer discovery conversations were conducted with 153 people in the ecosystem (60 patients, 30 caregivers, and 63 medical providers). Patients with upper-limb effects fell into two populations: spastic (stiff, clenched hands) and flaccid (limp hands). Focusing on the first category, a set of design constraints was developed based on the information collected from the customer discovery. With these in mind, the OrthoHand Extend was designed and prototyped as a powered wrist-hand stretching orthosis (exoskeleton) to aid in recovery. The orthosis was tested on two patients, one survivor of stroke and one of traumatic brain injury. Finally, a mathematical modeling technique was developed to characterize joint stiffness based on experimental testing. The prototype met most of the target design constraints and was able to consistently open both patients' hands. Donning and doffing times averaged 76 and 12.5 s, respectively, for each subject unassisted. These are approximately twice as fast than the next closest times shown in literature. This device has the potential as effective therapy devices accessible to patients in the home, and lays the foundation for clinical trials and further device development. The study was approved by the Vanderbilt University Institutional Review Board, study number 221203.
21 Dec 2023Submitted to TechRxiv
22 Dec 2023Published in TechRxiv