Efficacy And Stability Of Chronically-Implanted Intramuscular Electrodes
PublisherThe University of Arizona.
AbstractFunctional electrical stimulation involves artificial electrical stimulation of muscles with implanted electrodes to elicit movement in paralyzed limbs. Implanted electrodes often migrate from their site of insertion. Therefore, the purpose of this project was to develop and test an electrode system that: 1) minimizes electrode migration, 2) is biocompatible, 3) has small leads needed to accommodate large numbers of electrodes, and 4) is efficient to implant within one surgical session. Two electrode designs were tested: a dart (conically shaped) and an anchor (cylindrically shaped) electrode. Sixty electrodes of each type were surgically implanted into upper limb muscles of two rhesus macaque monkeys. The threshold stimulation needed to evoke contraction was measured on the day of surgery and on two occasions post-implantation. Only 46 dart and all 60 anchor electrodes remained functional several weeks after surgery. No biocompatibility problems were encountered. Threshold stimulation intensities were low (< 3.0 mA) and remained stable for up to 21 weeks following surgery. While preliminary, these results suggest that the anchor-type electrodes might serve as a stable and effective electrode for restoring movement with functional electrical stimulation.