Flexible dry electrode for recording surface electromyogram

A new type of flexible dry electrode is examined for its suitable for surface electromyography (SEMG). SEMG signals were collected from the both biceps of a subject, using the dry electrodes and standard AgAgCl electrodes, during three tasks: 1) rest, 2) an isometric contraction, and 3) a dynamic contraction. Signal quality indices (signal-to-motion artifact ratio, maximumto- minimum drop in power ratio, signal to noise ratio, and power spectrum deformation) were computed to assess the SEMG. Results show that the dry electrodes can acquire SEMG signals that are nearly indistinguishable from the SEMG signals acquired using the AgAgCl electrodes. The dry electrodes did appear to exhibit a slightly high susceptibility to motion artifact; however, the motion artifact remained below 10 Hz, which can be filtered out for most SEMG applications

Surface electromyographic signals using a dry electrode

A new flexible, dry electrode is examined for recording surface electromyographic signals and compared to a conventional Ag/AgCl electrode. A suitable dry electrode would enable practical implementation of wearable mobility monitoring systems. Results from a preliminary experiment are presented in this paper. Measurements were performed on the right tibialis anterior during a series of small and large contractions. The effects of skin preparation, which included shaving and cleaning with isopropyl alcohol, are also examined. Results show that the dry electrode is sensitive enough to detect the small, unloaded muscle contractions. The dry electrode signal strength was similar to the Ag/AgCl electrode; however, the noise level was higher by approximately 13.5±1.3 %. Skin preparation reduced the noise level by approximately 7.9% for the dry electrodes and 8.1% for the Ag/AgCl electrodes

Surface electromyographic signals using dry electrodes

For many electromyography (EMG) applications, a suitable dry electrode would simplify practical implementation of an EMG recording system. Wearable mobility monitoring is an example of such a system. Therefore, surface EMG signals, from Fraunhofer Institute for Biomedical Engineering (IBMT) flexible dry electrodes and Orbital Research electrodes, were compared to signals from conventional Ag/AgCl electrodes. EMG measurements were performed on the right tibialis anterior for a range of different activities, such as light twitches, isometric contractions, jumping, and walking. Signal feature comparisons, skin preparation effects (i.e., cleaning with isopropyl alcohol), and impedance-noise analyses were performed. Results showed that both dry electrodes had comparable sensitivity to the standard Ag/AgCl electrodes for detecting small unloaded muscle contractions and large loaded contractions. Results also showed that noise content and impedance are weakly correlated and skin preparation methods did not have a positive effect on skin/electrode impedance

Wearable EMG analysis for Rehabilitation (WEAR) - Surface electromyography in clinical gait analysis

This paper presents a new wearable electromyography (EMG) monitoring approach for gait analysis known as the Wearable EMG Analysis for Rehabilitation (WEAR) system. Conventional EMG acquisition uses single electrode pairs positioned above the muscle of interest, based on anatomical measurements. WEAR employs a dry electrode array, integrated in a wearable sleeve, which is quicker and easier to apply than the electrodes in a conventional system. An optimal electrode pair is automatically selected from the array, thus saving time and inherent cost. The WEAR system will be tested on 10 able-bodied subjects for intra-system repeatability, as well as direct comparison to outcomes from conventional surface EMG tests on the same set of participants

Continuous monitoring of mechanical properties of plantar soft tissue for diabetic patients using wearable ultrasonic and force sensors

Characterizing plantar soft tissue mechanical properties is essential to fully understand the potential for ulcer formation in diabetic patients. Ulcers initiate in the under layers of foot where soft tissues become stiffer. If changes in soft tissue stiffness can be detected early, foot ulcer formation may be prevented. Also, monitoring soft tissue mechanical properties could be beneficial for prosthetic and orthotic fitting, sport performance monitoring, and injury prevention and detection. This paper presents a method, using wearable ultrasonic and force sensors, for continuous monitoring of plantar soft tissue stiffness at the heel. With this method, simultaneous measurement of pressure and tissue displacement at the heel was performed and pressure-displacement curves were obtained while the person was stepping. This achievement establishes a basis for future research to assess mechanical properties of plantar soft tissues in real-time for foot ulcer screening

A novel approach to surface electromyography: An exploratory study of electrode-pair selection based on signal characteristics

A 3×4 electrode array was placed over each of seven muscles and surface electromyography (sEMG) data were collected during isometric contractions. For each array, nine bipolar electrode pairs were formed off-line and sEMG parameters were calculated and evaluated based on repeatability across trials and comparison to an anatomically placed electrode pair. The use of time-domain parameters for the selection of an electrode pair from within a grid-like array may improve upon existing electrode placement methodologies