Novel Body-Powered Prosthesis


The goal of this project is to evaluate the clinical utility of a voluntary open (VO)/voluntary close (VC) prehensor, or split-hook grasping device.

Despite a cultural fascination with robotic prostheses, many amputees still prefer using body-powered prostheses, in which users move their shoulder to operate the device.

Body-powered prehensors (split-hooks and other non-anthropomorphically shaped terminal devices) are considered more functional than body-powered hands, as they are durable and simple to manipulate.

Currently, however, users must choose between two types of prehensors: voluntary open (VO) devices, in which the user exerts force to open the device; and voluntary close (VC) devices, in which the user actively closes the device.

VO devices provide a weak grasp force of only a few pounds, but are easy to use. VC devices enable the user to apply large grasp forces but require the user to constantly exert force to hold an object.

With previous funding from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR), we developed a prehensor with an innovative yet simple manual switching system that enables a user to operate the device in either VO or VC mode. This VO/VC device can be used in the VO mode for manipulating light objects, and can easily be switched to VC mode to provide a high grasp force, when needed.

We plan to evaluate this device's clinical viability by objectively quantifying how amputees use these devices in their home environments.

Target Population

Persons with upper-limb amputations. This population comprises many thousands of people in the United States, including many combat-injured military service personnel, who are overwhelmingly young and active.

Related Publications


Sensinger JW, Lipsey J, Thomas A, and Turner K. Design and Evaluation of Voluntary Opening and Voluntary Closing Prosthetic Terminal DeviceJ Rehabil Res Dev, 52(1): 63-76, 2015


The contents of this webpage were developed under a grant from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR grant number 90RE5014-02-00). NIDILRR is a Center within the Administration for Community Living (ACL), Department of Health and Human Services (HHS). The contents of this webpage do not necessarily represent the policy of NIDILRR, ACL, HHS, and you should not assume endorsement by the Federal Government.

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