Selection of Optimal Muscle Set for 16-Channel Standing NeuroprosthesisBy Gartman, Steven J.; Audu, Musa L.; Kirsch, Robert F.; Triolo, Ronald J.; Journal of Rehabilitation Research and Development, Vol. 45, No. 7, pp. 1007-1018
Publication Date: 2008
Study undertaken to determine which muscles to target for optimal function of a 16-channel standing prosthesis. The prosthesis under development is the second generation of the Case Western Reserve University/Department of Veterans Affairs 8-channel lower-limb neuroprosthesis, which can restore standing to selected individuals with paraplegia by application of functional electrical stimulation (FES). With the addition of external orthoses to stabilize the ankle and a means to maintain balance, such as a walker, users of the system can transition from sitting and remain standing for an average of more than 10 minutes. The second generation of the system will include 16 channels of stimulation and a closed-loop control scheme to provide automatic postural corrections. A static musculoskeletal model that had 15 degrees of freedom and 40 muscles was used to determine whether a set of fixed postures could be maintained given a particular set of stimulated muscles. Results showed that the prime muscle targets should be the (1) medial gastrocnemius, (2) tibialis anterior, (3) vastus lateralis, (4) semimembranosus, (5) gluteus maximus, (6) gluteus medius, (7) adductor magnus, and (8) erector spinae. This set of 16 muscles supports 42 percent of the standing postures that are attainable by the nondisabled model. Co-activation of the lateral gastrocnemius and peroneus longus with the medial gastrocnemius and of the peroneus tertius with the tibialis anterior increased the percentage of feasible postures to 71 percent.
VA Rehabilitation Research & Development Service (Web Site: http://www.rehab.research.va.gov )
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