Body powered vs. myoelectric prosthesis [literature query]
I tried to look for comparisons that extend my one person plus lots of anecdotal evidence viewpoints.
Comparison is between body powered and myoelectric arms but I include papers regarding specific myoelectric options as well. Myoelectric technology seems to be quite clearly the more difficult to build, more expensive, less satisfactory and far more uncomfortable approach to cleaning up the prosthetic situation after an upper extremity amputation, particularly for transradial amputees with intact residual limbs and with intact vision.
But then, sales is a major factor. If customers can be pushed to use such an arm, if the body powered solution is built sloppily, if the orthopedic technician earns more money selling higher priced material than when selling lower priced material (and that may be the case in any given instance, it is definitely the case for some), then any concise comparison may end up highly distorted.
J Hand Surg Br. 1997 Feb;22(1):73-6. Upper limb traumatic amputees. Review of prosthetic use. Gaine WJ, Smart C, Bransby-Zachary M. Orthopaedic Department, Southern General Hospital, Glasgow, UK. -- The prosthetic status of the traumatic upper limb amputees was reviewed. Fifty-five upper limb amputees were reviewed using a detailed questionnaire, telephone or clinic review and by case note study. Twenty-three patients were traumatic amputees and 32 were congenital amputees. The amputees' function, prosthetic use and satisfaction were evaluated and this formed the basis of a scoring system. The traumatic group were less satisfied with their prosthesis and their functional ability was poorer, especially in the use of the myoelectric prosthesis. Traumatic amputees were their prosthesis for an average of 6.5 hours per day compared to 9.3 hours in the atraumatic group. None of the traumatic amputees fitted after 12 weeks returned to gainful employment. Early prosthetic fitting, rehabilitation and post-traumatic counselling are advocated in upper limb traumatic amputees in order to achieve an optimum prosthetic benefit for the patient.
J Pediatr Orthop. 1993 Jan-Feb;13(1):68-75. Myoelectric and body-powered prostheses. Kruger LM, Fishman S. - One hundred twenty below-elbow child amputees compared cosmetically identical myoelectric (MYO) and body-powered (BP) hands after wearing each for 3 months; 78% chose the MYO and 22% chose the BP. However, at 2-year follow-up, only 44% wore the MYO, 33% used a BP hand or hook, and 23% became nonwearers (NW). Eighty percent of children aged > or = 8 years used active prosthetic prehension for both the MYO and BP prostheses. Comparatively, only 30% aged < 8 years and 0% aged < 5 years demonstrated any active prosthetic prehension. Active BP wearers were clearly most pleased with the features of their prostheses.
Arch Phys Med Rehabil. 1993 Apr;74(4):376-80. Performance comparison among children fitted with myoelectric and body-powered hands. Edelstein JE, Berger N. Prosthetics and Orthotics, New York University Post-Graduate Medical School, New York. - Seventy-six children with unilateral below-elbow amputation were fitted in random sequence with a myoelectric (MYO) and a body-powered (BP) prosthetic hand of identical size, shape, and glove color. Subjects ranged from six to 17 years, nine months and included 67 children with congenital limb deficiency and nine who sustained traumatic amputation. After training, each child wore each hand for three months. On the form board test requiring only prosthetic use, subjects took 13.7% longer with the MYO and committed more errors with the MYO, specifically in dropping objects and delaying their grasp and release. Object displacement, the most common error, occurred nearly as often with BP as MYO. MYO was minimally faster on a test of ten practical activities designed for bimanual prehension. Card playing was 39.8% faster with BP, whereas donning socks, cutting paper, and bandage application were 27.8%, 12.5%, and 10.9% faster with MYO. Performance with both hands was rated as decidedly poorer than normal quality. No major clinically important differences were found in the comparison of performance.
Prosthet Orthot Int. 1992 Apr;16(1):32-7. Functional benefit of an adaptive myoelectric prosthetic hand compared to a conventional myoelectric hand. Bergman K, Ornholmer L, Zackrisson K, Thyberg M. Department of Rehabilitation Medicine, Linköping University Hospital, Sweden. -- Eight patients with a traumatic unilateral upper limb amputation, who used conventional myoelectric prostheses, were also fitted with a commercially available myoelectric prosthetic hand with an adaptive grip, in order to compare the functional benefit of the two types of prostheses. Comparisons were made regarding width of grip, force of grip, scores in a standardised grip function test and prosthesis preference. The conventional prosthesis showed significantly better results regarding these parameters. The adaptive hand does not appear to be fully developed for practical use in prosthetic rehabilitation.
Prosthet Orthot Int. 2007 Dec;31(4):362-70. Results of an Internet survey of myoelectric prosthetic hand users. Pylatiuk C, Schulz S, Döderlein L. Forschungszentrum Karlsruhe, Institute for Applied Computer Science, Karlsruhe, Germany. email@example.com -- The results of a survey of 54 persons with upper limb amputations who anonymously completed a questionnaire on an Internet homepage are presented. The survey ran for four years and the participants were divided into groups of females, males, and children. It was found that the most individuals employ their myoelectric hand prosthesis for 8 hours or more. However, the survey also revealed a high level of dissatisfaction with the weight and the grasping speed of the devices. Activities for which prostheses should be useful were stated to include handicrafts, personal hygiene, using cutlery, operation of electronic and domestic devices, and dressing/undressing. Moreover, additional functions, e.g., a force feedback system, independent movements of the thumb, the index finger, and the wrist, and a better glove material are priorities that were identified by the users as being important improvements the users would like to see in myoelectric prostheses.
JPO Journal of Prosthetics & Orthotics. 8(1):2-11, Winter 1996. Epidemiologic Overview of Individuals with Upper-Limb Loss and Their Reported Research Priorities. Atkins, Diane J. OTR 1; Heard, Denise C Y MSE 2; Donovan, William H. MD 3 -- More than 6,600 one-page surveys were sent to individuals throughout the country with upper-limb loss or absence. Of those surveys, 2,477 were returned, and demographic information was recorded. A more comprehensive seven-page survey was then sent to the respondents who agreed to participate. A total of 1,575 of these surveys were returned: 1,020 by body-powered users, 438 by electric users and 117 by bilateral users of prostheses. The results of the surveys indicate users of body-powered and electric prostheses identify surprisingly similar elements as necessary in the design of a better upper-limb prosthesis. These qualities include additional wrist movement, better control mechanisms that require less visual attention and the ability to make coordinated motions of two joints. Desired near-term improvements for body-powered prostheses include better cables and harness comfort, whereas those for electric prostheses include better gloving material, better batteries and charging units, and improved reliability for the hand and its electrodes. This article discusses the specific functions that various levels of upper-extremity amputees gain from their prostheses as well as the device features that aid or detract from their functions.
Prosthet Orthot Int. 1998 Dec;22(3):216-23. An evaluation of the use made of cosmetic and functional prostheses by unilateral upper limb amputees. Fraser CM. Occupational Therapy Services, Addenbrooke's NHS Trust, Cambridge, UK. firstname.lastname@example.org -- There is currently a distinction drawn between a prosthesis considered to be provided for purely cosmetic reasons and a functional prosthesis provided to enable the amputee to achieve basic hand function. Using video analysis the study reported in this paper demonstrates that for non-manipulative actions cosmetic prostheses are actively used in the performance of everyday tasks as frequently as functional prostheses. The study provides evidence for a cosmetic prosthesis to be presented to an amputee as a realistic initial prosthesis and not as the option of last resort if a functional prosthesis is rejected. It is also recommended that training is provided in the use of cosmetic prostheses in two-handed tasks.
Myoelectric control error rates: in about four decades, academically published myoelectric arm control error rates remained (a) unacceptably high and (b) became slightly worse [very detailed analysis here].