Neuromodulation : journal of the International Neuromodulation Society
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We present data collected from a multicenter study using a new neurostimulation system. This new system uses a current-shifting programming technique for spinal cord stimulation. The system maintains a continuous, suprathreshold stimulation field while adjusting the distribution of anodic and cathodic current among contacts along a multi-contact array. ⋯ This multicenter study evaluated the performance of the CEFA technique. The results of the study showed that paresthesia coverage could be shifted in real-time to different regions on the patient's body in a comfortable fashion, with the patient always feeling paresthesia during the adjustment process. The results of the study also show that the process was time-efficient: intraoperatively, the median time to assess 71 combinations on a single 8-contact lead across 18 patients was 4.1 (3.6-5.0) minutes.
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We report on the use of a new percutaneous technique for peripheral nerve stimulation (PNS) treatment of chronic pain. A 56-year-old woman was diagnosed with algodystrophic syndrome, now called Complex Regional Pain Syndrome, type 2 (CRPS2), due to a lesion of the right medial nerve despite surgical revascularization, angioplasty and stent insertion. ⋯ After one year of follow-up, the patient was still experiencing good pain relief. We conclude that this novel percutaneous PNS technique offers the advantage of being a minimally invasive approach that can be easily adopted for the management of chronic pain.
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We had shown in our previous research that the stability assessment and control are essential for generation of faster and more energy efficient functional electrical stimulation (FES) and/or crutch-assisted gait. The objective of our recent research work has been to design a wearable and portable system for gait stability analysis with online capabilities that is also applicable to crutch-assisted gait modes. The developed wearable stability assessment system for as yet only biped gait consists of foot switches and goniometers attached to the leg joints. ⋯ The wearable system was tested on five healthy subjects and one above-knee amputee. It proved to be reasonably accurate if compared to the classical, motion analysis system based method. However, additional work is required to port the system to the FES assisted and/or crutch assisted gait.
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The objective of this study was to develop and test the feasibility of a model that employs electromyographic (EMG) signals to predict the occurrence of gait events in the child with cerebral palsy (CP). This model could be the basis of a future functional electrical stimulation (FES) control system to assist gait. Two children were implanted with bifilar intramuscular electrodes into the quadriceps muscle bilaterally. ⋯ For nine of the 10 gait events evaluated, the model predicted gait events to within 82 ms on average, as referenced to the VICON motion analysis system. For eight of the 10 events, prediction errors were 0.3% or less. Results indicate that EMG from the proximal musculature could be used to predict the occurrence of gait events in these two children with CP.
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This study investigated the activation dynamics of electrical stimulation-evoked muscle contractions performed by individuals with spinal cord injury (SCI). The purpose was to determine whether electrical stimulation (ES) firing patterns during cycling exercise should be altered in response to fatigue-induced changes in the time taken for force to rise and fall with ES. Seven individuals with SCI performed isometric contractions and pedaled a motorized cycle ergometer with stimulation applied to the quadriceps muscles. ⋯ Cycling power output fell approximately 50% during the five minutes of exercise, however, there was no change in the time taken for torque to rise or fall. The magnitude of ES-evoked muscle torques decline substantially with fatigue, however, the overall pattern of torque production remained relatively unchanged. These results suggest there is no need to alter stimulation firing patterns to accommodate fatigue during ES-evoked exercise.