Spinal Cord Injury
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Journal of Rehabilitation Research and Development Rehabilitation R & D Progress Reports 1983 Spinal Cord Injury A. Electrical Stimulation and Gait Analysis B. Robotics C. Mobility Aids 1. Wheelchairs 2. Wheelchair Accessories 3. Controllers and Lifts 4. Decubitus Ulcers Cushions 5. Automotive Adaptive Equipment D. ADL and Recreation E. Treatment and Training F. Diagnostics and Information G. Spinal Trauma H. Musculoskeletal Rehabilitation I. Information 45 m m~h m.~~~~0NN~~~~ Cord Injury R&D In this section, under the heading of Spinal wrist and finger motions were recorded while the Cord Injury R&D, reports in the following general primate performed the tracking tasks . The signals areas will be found : Electrical Stimulation and Gait were processed and analyzed using odiQita! oomn- Analysis ; Robotics; Mobility Aids including Wheel- puter.The preliminary results indicate a correlation chairs, Wheelchair Accessories, Controllers and between the intended task and neuroelectric activity Lifts, Decubitus Ulcer/Seat Cushions, Automotive in each nerve E Adaptive Equipment; ADL and Recreation ; Treatment and Training; Diagnostics and Information ; Spinal Trauma, Musculoskeletal Rehabilitation ; Information. ! RESTORATION OF UPPER LIMB FUNCTION [-/-~-~~l!-A! THROUGH FES -_-- _ F~ P. Hunter D.; Alvin u^Frewhater, M.D.; Michael W. ~~ ~. Keith, M.D.; and E. B. Marsolais, Ph. D., M.D. Rehabilitation Engineering Center Case Western Reserve University GAIT A\A !S Cleveland and Metropolitan General/Highland View Hospitals, Dept. of Orthopaedics 3395 Scranton Rd ., Cleveland, Ohio 44109 LIBERTY MUTUAL, NIHR, SWEDEN These studies are the core area of research in the VOLUNTARY NERVE SIGNALS FROM PRIMATES center. The purpose of the project is to develop and L. Jack Bloom, B.G.S., and Donald Gilmore, A.B.E.E. evaluate systems employing functional electrical NeuroMuscular Research Laboratory stimulation to provide control of hand movement. These studies are being performed in conjunction Children's Hospital Medical Center with the VA Rehabilitation Engineering R&D pro- Boston, Massachusetts 02115 gram, and the current status is detailed in a progress and n Liberty Mutual Research Center report that appears elsewhere in this issue Hopkinton, Massachusetts 01748 In order to control additional degrees of freedom in our e!ectnonnechanioal prosthesis (the Boston VAMC CLEVELAND , Elbow) according to our concept of using control FUNCTIONAL NEUROMUSCULAR SYSTEMS signals most directly related to the movement to be FOR UPPER EXTREMITY CONTROL duplicated, neuroelectrical signals obtained from the severed nerves in the arm will be required . An P. Hunter Peckham, Ph . D.; Alvin A. Feehater, M.D.; Michael W. elaborate experiment was initiated using a primate Keith, M .D:andE. ByrwnMwrsolmks, M .D., Ph. D. trained to perform movements duplicating two de- Veterans Administration Medical Center sired functions of the Boston Elbow . By using either 10101 East Boulevard, Cleveland, Ohio 44106 wrist or finger movements, the primate was trained Case Western Reserve University Cleveland Metropolitan General/Highland View Hospital to track a computer-generated moving target . A juice 3395 Scranton Rd ., Cleveland, Ohio 44109 reward was given for each correct response and the computer kept score of the results . After the training period was completed, two of our previously de- Part 1 . Development of Upper Extremity Orthoses signed recording electrode units were successfully Employing Electrical Stimulation implanted in its arm around each of the two nerves Aneupoproathetiosystem has been developed to controlling finger extension/flexion and wrist rota- restore upper-extremity control through application tion. Both sensory and motor-nerve signals from of funotional neuromuscular stimulation . This tech- 46 SPINAL CORD INJURY nique enables the C5 and C6 !evel quadriplegic to be fitted with tthey utilize his hand functionally. cally stable and ready to accept an assistive device. Thirteen patients have been provided with the FES System Description -- Subjects with C5 or C6 !evel hand assist system. function are candidates for use of the system. Con- Patients use the system for combing hair, brushing trol of the system employs a voluntary command teeth, applying toothpaste to toothbrush, shaving generated by the patient to activate coordinated with electric or safety razor, washing face and neck, movement of the hand . This voluntary command eating and drinking, writing, and self-catheterization. proportionally regulates the output of up to four The patient wears his neuroprosthesis throughout channels of stimulation .The stimulus output of each the day to have the flexibility of independently per- channel is modulated according to a coordination forming a functional task at his discretion. algorithm determined in laboratory studies, to pro- The present system has had 344 user-months of vide satisfactory motion for the set of muscles and evaluation . Some of the problems encountered in- electrodes employed in the particular individual. clude external cables (connecting electrodes and control transducer to the stimulator) which are en- System Implementation — Muscles to be stimulated cumbering, and percutaneous electrodes which re- are those which can be used to provide either a quire maintenance of the implant site . (To overcome lateral prehension/release or palmar prehension/ these problems, we are presently developing an im- release and have the lower motor neuron intact. plantable stimulator .) However, despite these defi- Generally eight or nine muscles are implanted, ciencies, at the present level of development the including the finger flexors (flexor digitorum super- FES system is sufficiently reliable and functional ficialis and profundus), finger and thumb extensors and it is, in general, prescribed and used as the (extenao,digitorunn communis and extensor pollicus primary functional orthosis for high level spinal in- longus), and thumb intrinsics (abductor pollicus jury patients at our Center. brovia,flexor po!!iuuoboovie,andadductor po!!ioua). These muscles are implanted with percutaneous coiled wire electrodes. Portable Functional Electrical Stimulation System Part 2. Implantable - A portable functional electrical stimulation system for Stimulation of Skeletal Muscle utilizing a microprocessor has been developed. In- corporation of the microprocessor has resulted in a An implantable user device which can be programmed to accept and oped using semi-custom integrated circuit technology. process a variety of user-generated commands and The unit is reliable, small, lightweight, has low power tooutput complicated stimulus patterns. Theavail- consumption, allows freedom of movement, and is ability of these enhanced stimulus regimes and intended for permanent usage. more complex user-control algorithms enable us to The stimulator circuitry is externally controlled tailor the device to a larger population of potential and powered by a single encoded radio-frequency users. powering carrier. Up to eight independently controlled System Use : The microprocessor-based portable stimulus output channels are provided, with the out- e!aotrical stimulation system has provided us with a put channel selection, stimulus pulse width, and functionally more povv grful system than our earlier stimulus pulse frequency all under external control. discrete logic systems. The advantages that are most A constant-current biphasic stimulus pulse is used, evident are the simplicity in fabrication of each unit, in which the stimulus current amplitude can be pro- the ease in establishing input control processing and grammed by a single resistor value . The stimulator output stimulation schemes, and the fact that each circuitry has been implemented in thick film hybrid unit is identical and not patient-specified prior to the form, and has been undergoing laboratory evaluation assembly of the device . With previous systems, for 16 months. much time was spent in hardware fabrication due to The stimulator circuitry has been encapsulated in variations in the user control algorithm. glass-ceramic packages for use with long-term ani- mal evaluation . Hermetically sealed titanium pack- Patients' Use of Functional Stimulation System aging, suitable for implantation in human subjects, Subjects are provided with the functional system for is currently being developed . Stimulating electrodes training and use . The use of the system is incorpor- have been developed that are mechanically reliable ated into the regular inpatient occupational therapy and provide stable stimulus characteristics. program. The occupational therapist and rehabilita- Both laboratory testing and animal evaluation tion engineer jointly train the subject . Patients may have been performed . In vitro studies are ongoing to 47 Rehabilitation R&D Progress Reports 1983 determine the responses of the electrodes to extended single muscles ought to be coordinated for the body periods of stimulation. Animal evaluation has been to achieve a specific motor task . Critical to these used to address the overall system performance; models is a representation of muscle that uses the stimulators have been operational in animals for fundamental properties of muscle as a basis, and more than 10 months. yet is simple enough for computer implementation. The development of this system consists of three We chose an approach to muscle modeling that is main areas ; electronics, packaging, and stimulation robust. It purports that generic to skeletal