A pairing of technologies
A Web-exclusive sidebar accompanying our August 2007 cover story, "Bridges to the brain."
Lawrence D. Maloney -- Test & Measurement World, 8/1/2007
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Kirsch: Thorough groundwork needed. |
Robert Kirsch, a PhD biomedical engineer based at Case University and the Cleveland FES Center, is principal investigator in a project that would use BrainGate to control an implanted functional electrical stimulator (FES) to activate muscles in the hand and arm. This particular system (see figure) would use telemetry to transfer brain signals to the external decoding processor and would also employ an exterior mobile-arm support. Funded in part by a $4.5 million grant from the National Center for Rehabilitation Research, the project seeks to devise a system that will have a significant impact on a user’s independence, including the ability to eat, drink, and perform self-care activities.
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The Cleveland FES Center is conducting a research project that will use BrainGate to control an implanted functional electrical stimulator to activate muscles in the hand and arm. Kirsch’s team has constructed a mathematical model of the system, called the Dynamic Arm Simulator (DAS). Courtesy of the Cleveland FES Center. |
“The big challenge in a system like this, where there is invasive surgery, is to do thorough groundwork so we have the confidence that it will be effective,” said Kirsch. As part of that process, Kirsch’s team has constructed a mathematical model of the system, called the Dynamic Arm Simulator (DAS). Developed with the MathWork's Simulink tool and the SIMM biomechanics modeling package from Motion Analysis Corp., the DAS is a realistic, dynamic musculoskeletal model of an FES-driven human arm and hand.
Another software package, SD-Fast, distributed by PTC, generates equations of motion for the DAS. Among other things, the researchers use this simulator to develop cortical control algorithms that can provide patients with upper extremity function before they actually receive an implanted FES system. Patients currently participating in the study use brain signals to control the simulated arm while viewing an animation of this arm on the computer screen.
Much work needs to be done before BrainGate is used along with an FES implant, but Kirsch believes that adding neural interface technology could offer some significant enhancements to existing FES systems. Said Kirsch: “If we want to give people the ability to control multiple functions of the arm, along with the hand, it is essential that we develop a better system than we now have.”
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