IEEE transactions on bio-medical engineering
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IEEE Trans Biomed Eng · Jan 2009
A strategy for identifying locomotion modes using surface electromyography.
This study investigated the use of surface electromyography (EMG) combined with pattern recognition (PR) to identify user locomotion modes. Due to the nonstationary characteristics of leg EMG signals during locomotion, a new phase-dependent EMG PR strategy was proposed for classifying the user's locomotion modes. The variables of the system were studied for accurate classification and timely system response. ⋯ For eight able-bodied subjects, the average classification errors in the four defined phases using ten electrodes located over the muscles above the knee (simulating EMG from the residual limb of a TF amputee) were 12.4% +/- 5.0%, 6.0% +/- 4.7%, 7.5% +/- 5.1%, and 5.2% +/- 3.7%, respectively. Comparable results were also observed in our pilot study on the subjects with TF amputations. The outcome of this investigation could promote the future design of neural-controlled artificial legs.
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IEEE Trans Biomed Eng · Jan 2009
Implantable myoelectric sensors (IMESs) for intramuscular electromyogram recording.
We have developed a multichannel electrogmyography sensor system capable of receiving and processing signals from up to 32 implanted myoelectric sensors (IMES). The appeal of implanted sensors for myoelectric control is that electromyography (EMG) signals can be measured at their source providing relatively cross-talk-free signals that can be treated as independent control sites. An external telemetry controller receives telemetry sent over a transcutaneous magnetic link by the implanted electrodes. ⋯ We have a fully operational system. The system has been tested in animals. Implants have been chronically implanted in the legs of three cats and are still completely operational four months after implantation.
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IEEE Trans Biomed Eng · Jan 2009
The role of slow potassium current in nerve conduction block induced by high-frequency biphasic electrical current.
The role of slow potassium current in nerve conduction block induced by high-frequency biphasic electrical current was analyzed using a lumped circuit model of a myelinated axon based on the Schwarz-Reid-Bostock model. The results indicate that nerve conduction block at stimulation frequencies above 4 kHz is due to constant activation of both fast and slow potassium channels, but the block at stimulation frequencies below 4 kHz could be due to either anodal or cathodal dc block depending on the time of the action potential arriving at the block electrode. ⋯ The blocking location moved from the node under the blocking electrode to a nearby node as the stimulation intensity increased. This simulation study reveals that in mammalian myelinated axons, the slow potassium current probably plays a critical role in the nerve conduction block induced by high-frequency biphasic electrical current.
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IEEE Trans Biomed Eng · Nov 2008
Automatic real-time ECG coding methodology guaranteeing signal interpretation quality.
This paper introduces a new methodology for compressing ECG signals in an automatic way guaranteeing signal interpretation quality. The approach is based on noise estimation in the ECG signal that is used as a compression threshold in the coding stage. ⋯ Three cardiologists have participated in the clinical trial using mean opinion score tests in order to rate the signals quality. Results showed that the approach not only achieves very good ECG reconstruction quality but also enhances the visual quality of the ECG signal.
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IEEE Trans Biomed Eng · Nov 2008
Manikins with human-like chest properties--a new tool for chest compression research.
Commercially available training manikins for cardiopulmonary resuscitation (CPR) do not accurately mimic the mechanical properties of human chests. This may limit the usefulness of CPR research performed on such manikins. This paper presents the construction of manikins with chest properties matching those measured in patients during an ongoing CPR. ⋯ The stiffness and damping of the manikins were verified using the same equipment and method as was used during data collection. Between 30 and 50 mm compression depth, the force-depth relationship of all eight manikins were found to be within +/-30 N of force or +/-2 mm of depth from the reference specifications derived from measurements on patients' chests. The average damping was also found to closely match the specified value.