Determining the Functional Importance of a Powered Multifunction Wrist
Abstract
Objectives and Rationale: Loss of an arm causes profound difficulty in performing everyday tasks such as eating or dressing. Because of the dexterity of the intact arm and hand, replacing the missing limb with a prosthesis is difficult. For people who use a myoelectric prosthesis, i.e., one that is controlled by electrical signals generated by muscles on the residual limb, most available hands are simple devices that only allow open and close. Recent advances have led to more sophisticated hands that provide multiple grasps, but these complicated devices are expensive and difficult to control using standard control techniques. The only myoelectric wrists currently available provide rotation but cannot flex (bend forwards) or extend (bend backwards); this makes it hard for the user to position their hand in the correct place and means that they often have to do things more slowly or awkwardly. At the Rehabilitation Institute of Chicago (RIC), we have recently developed a wrist (the RIC wrist) that provides rotation, flexion, and extension, and we have developed a new, easier way of controlling prosthetic devices, called pattern recognition (PR). Recently, another research group has shown, in able-bodied people, that combining a simple hand with a wrist that can rotate, flex, and extend is as useful as pairing an intact hand with a wrist that only allows rotation. In other words, a more useful wrist makes a simple hand much more useful. The objective of our study is to use our RIC wrist to find out how having either one or two available wrist movements, when combined with a simple hand, affects function of a prosthesis. The rationale for this study is that this information will help clinicians and patients understand the benefits of a more functional wrist, and, importantly, help individuals with amputation achieve better function with their device. This study will also provide the necessary clinical data for us to take the next steps toward making the RIC wrist commercially available to Service personnel and civilians with arm loss. Applicability and Potential Impact of the Research: This research addresses the need for improved prosthetic function for individuals with upper arm amputation. By combining our more useful wrist with PR control, we may be able to improve the function of even simple prosthetic hands. The wrist is compatible with most commercial prosthetic hands, so users will be able to select the hand that they prefer, or continue to use their own, and will be able to control both the hand and the wrist easily and effectively using PR. Who Will Be Helped by This Research: Estimates suggest that 41,000 people are living with an arm amputation above the wrist level in the US, and more than 350 Service personnel experienced major upper limb amputations resulting from combat in Iraq and Afghanistan. In both the civilian and military populations, arm loss affects young people who need prostheses that are both functional and easy to control so that they can resume an active, independent lifestyle. Persons with arm amputation will be helped by this research, as this study will determine how having more wrist movements will improve prosthetic function. This information can be used to help choose the best prosthetic components to optimize the user’s ability to perform everyday tasks and leisure activities, and perhaps return to work or active duty. While advanced hands that provide many grasps are becoming available, they are expensive and prone to breakage. Combining a more useful wrist with a simple hand may be cheaper and stronger. Clinical Applications, Benefits, and Risks: This research is the first necessary step toward commercialization of the RIC wrist; thus, the eventual clinical application of this research would be to bring the wrist to market for the benefit of people with amputations. The risks to users of the RIC wrist are minimal, so long as it is used in ways that are compati
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 29, 2018
- Source ID
- W81XWH1710332
Entities
People
- Levi J. Hargrove
Organizations
- Shirley Ryan AbilityLab
- United States Army