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Timing cues such as interaural time differences (ITDs) and temporal pitch are pivotal for sound localization and source segregation, but their perception is degraded in cochlear-implant (CI) listeners as compared to normal-hearing listeners. In multi-electrode stimulation, intra-aural channel interactions between electrodes are assumed to be an important factor limiting access to those cues. The monaural asynchrony of stimulation timing across electrodes is assumed to mediate the amount of these interactions. This study investigated the effect of the monaural temporal electrode asynchrony (mTEA) between two electrodes, applied similarly in both ears, on ITD-based left/right discrimination sensitivity in five CI listeners, using pulse trains with 100 pulses per second and per electrode. Forward-masked spatial tuning curves were measured at both ears to find electrode separations evoking controlled degrees of across-electrode masking. For electrode separations smaller than 3 mm, results showed an effect of mTEA. Patterns were u/v-shaped, consistent with an explanation in terms of the effective pulse rate that appears to be subject to the well-known rate limitation in electric hearing. For separations larger than 7 mm, no mTEA effects were observed. A comparison to monaural rate-pitch discrimination in a separate set of listeners and in a matched setup showed no systematic differences between percepts. Overall, an important role of the mTEA in both binaural and monaural dual-electrode stimulation is consistent with a monaural pulse-rate limitation whose effect is mediated by channel interactions. Future CI stimulation strategies aiming at improved timing-cue encoding should minimize the stimulation delay between nearby electrodes that need to be stimulated successively.

Abstract Introduction Congenital Central Hypoventilation Syndrome (CCHS) is a genetic disorder that results in the loss of autonomic ventilatory control, and patients require ventilatory support during sleep or both sleep and wakefulness. One method of ventilatory support is diaphragm pacing (DP), where electrodes surgically placed on the phrenic nerve are connected to subcutaneously implanted receivers that communicate with external antennas and transmitter. There are limited data on the frequency of DP malfunctions that require surgical revision. Methods We reviewed the records of 24 CCHS patients ventilated by DP followed at CHLA from 1990-2019. Records were examined for demographics, PHOX2B mutation, pacing duration/day, date and type of malfunctions, age and time since implantation at malfunction occurrence, and repair success rate. Results All 24 patients had thoracoscopic electrode placement. 17/24 (71%) of patients used DP while asleep; 3/24 (13%) during wakefulness only. 4/24 (17%) were not currently using their pacers. 10/24 (42%) patients required at least one surgical intervention (Age at implantation 9 ± 4.6 (SD) years; age at malfunction 12.5 ± 7.4 years). The average time from pacer implantation to malfunction was 3.8 ± 3.5 years. Malfunctions included defective receivers (6), insulation leaks (1), defective electrodes (4), and hardware infection (1). Of 12 unique component repairs, 6/12 (50%) involved changing receivers, 1/12 (8%) involved repairing an insulation leak, 4/12 (33%) involved replacing the electrodes and receivers, and 1/12 (8%) involved hardware extraction. Of the 12 malfunctions, 10 (83%) had successful surgical revision. 2/12 (17%) repairs were not attempted. While awaiting surgical revision, patients were successfully ventilated by unilateral DP. Conclusion Nearly half of CCHS patients on DP experienced malfunctions within 11 years of implantation. The most common DP repair was receiver replacement. Patients who are waiting for repair often successfully ventilate while pacing unilaterally. Support None

Abstract Introduction Upper airway stimulation is a option for CPAP-intolerant patients. Device activation is typically ~4 weeks after the implant procedure. Report of Case A 61yo male with severe OSA had an upper airway stimulation device placed by ENT. At that time, stimulation produced bilateral tongue protrusion. In the immediate post-operative period, after closure, a hematoma, at the inferior chest incision, was discovered and drained with cauterization of the bleeding vessel. Seven weeks after implant, patient reported to our sleep clinic for activation of the device; and at that time, there was no sensation or activation up to the maximum amplitude of 5mV. The device reported an acceptable respiratory waveform, and triggering on and off sets but without sensory outcomes. Changing of the electrode configuration with advanced settings had no effect. Impedance values were acceptable. Tongue movements were grossly intact. At 2 months, ENT evaluation found mild hypoglossal nerve neuropraxia. To assess for a device related issue, x-rays of the neck and chest were performed and showed proper placement of the device. At 3.5 months, neuropraxia had resolved but device activation was unsuccessful, with no sensory or motor activation to 5mV stimulation. Plans were made for a procedure during which the lead electrode or implantable pulse generator would be assessed or replaced. At 4 months after implantation, in a multidisciplinary appointment with Sleep, ENT and the device representative, with a 3 electrode negative pole and the generator as the + pole, at 2.3mV, the device was activated. At the present time, the patient is exploring higher and lower mV settings and a PSG titration is scheduled. Conclusion This is the longest recorded duration (3.5+ months) of unsuccessful post-operative activation; and it occurred ~2 months after clinical signs of hypoglossal nerve neuropraxia had resolved.

Textile electromyography (EMG) electrodes embedded in clothing allow muscle excitation to be recorded in previously inaccessible settings; however, their ability to accurately and reliably measure EMG during dynamic tasks remains largely unexplored. To quantify the validity and reliability of textile electrodes, 16 recreationally active males completed two identical testing sessions, within which three functional movements (run, cycle and squat) were performed twice: once wearing EMG shorts (measuring quadriceps, hamstrings and gluteals myoelectric activity) and once with surface EMG electrodes attached to the vastus lateralis, biceps femoris and gluteus maximus. EMG signals were identically processed to provide average rectified EMG (normalized to walking) and excitation length. Results were compared across measurement systems and demonstrated good agreement between the magnitude of muscle excitation when EMG activity was lower, but agreement was poorer when excitation was higher. The length of excitation bursts was consistently longer when measured using textile vs. surface EMG electrodes. Comparable between-session (day-to-day) repeatability was found for average rectified EMG (mean coefficient of variation, CV: 42.6 and 41.2%) and excitation length (CV: 12.9 and 9.8%) when using textile and surface EMG, respectively. Additionally, similar within-session repeatability (CV) was recorded for average rectified EMG (13.8 and 14.1%) and excitation length (13.0 and 12.7%) for textile and surface electrodes, respectively. Generally, textile EMG electrodes appear to be capable of providing comparable muscle excitation information and reproducibility to surface EMG during dynamic tasks. Textile EMG shorts could therefore be a practical alternative to traditional laboratory-based methods allowing muscle excitation information to be collected in more externally-valid training environments.

Bioelectrical or electrophysiological signals generated by living cells or tissues during daily physiological activities are closely related to the state of the body and organ functions, and therefore are widely used in clinical diagnosis, health monitoring, intelligent control and human-computer interaction. Ag/AgCl electrodes with wet conductive gels are widely used to pick up these bioelectrical signals using electrodes and record them in the form of electroencephalograms, electrocardiograms, electromyography, electrooculograms, etc. However, the inconvenience, instability and infection problems resulting from the use of gel with Ag/AgCl wet electrodes can’t meet the needs of long-term signal acquisition, especially in wearable applications. Hence, focus has shifted toward the study of dry electrodes that can work without gels or adhesives. In this paper, a retrospective overview of the development of dry electrodes used for monitoring bioelectrical signals is provided, including the sensing principles, material selection, device preparation, and measurement performance. In addition, the challenges regarding the limitations of materials, fabrication technologies and wearable performance of dry electrodes are discussed. Finally, the development obstacles and application advantages of different dry electrodes are analyzed to make a comparison and reveal research directions for future studies.

Neural recording electrode technologies have contributed considerably to neuroscience by enabling the extracellular detection of low-frequency local field potential oscillations and high-frequency action potentials of single units. Nevertheless, several long-standing limitations exist, including low multiplexity, deleterious chronic immune responses and long-term recording instability. Driven by initiatives encouraging the generation of novel neurotechnologies and the maturation of technologies to fabricate high-density electronics, novel electrode technologies are emerging. Here, we provide an overview of recently developed neural recording electrode technologies with high spatial integration, long-term stability and multiple functionalities. We describe how these emergent neurotechnologies can approach the ultimate goal of illuminating chronic brain activity with minimal disruption of the neural environment, thereby providing unprecedented opportunities for neuroscience research in the future.Here, Hong and Lieber review recent developments in electrode technologies for the recording of single-unit spiking activity. They focus on advances in electrodes with high spatial integration, long-term stability and multifunctional capacities.

Dielectric particles in a non-uniform electric field are subject to a force caused by a phenomenon called dielectrophoresis (DEP). DEP is a commonly used technique in microfluidics for particle or cell separation. In comparison with other separation methods, DEP has the unique advantage of being label-free, fast, and accurate. It has been widely applied in microfluidics for bio-molecular diagnostics and medical and polymer research. This review introduces the basic theory of DEP, its advantages compared with other separation methods, and its applications in recent years, in particular, focusing on the different electrode types integrated into microfluidic chips, fabrication techniques, and operation principles.

From mobile devices to the power grid, the needs for high-energy density or high-power density energy storage materials continue to grow. Materials that have at least one dimension on the nanometer scale offer opportunities for enhanced energy storage, although there are also challenges relating to, for example, stability and manufacturing. In this context, Pomerantseva et al. review fundamental processes of charge storage that apply specifically to nanostructured materials and briefly explore potential manufacturing processes. The authors also consider some of the skepticism, such as that found in the battery community, to the use of these materials. Science , this issue p. eaan8285 Lithium-ion batteries, which power portable electronics, electric vehicles, and stationary storage, have been recognized with the 2019 Nobel Prize in chemistry. The development of nanomaterials and their related processing into electrodes and devices can improve the performance and/or development of the existing energy storage systems. We provide a perspective on recent progress in the application of nanomaterials in energy storage devices, such as supercapacitors and batteries. The versatility of nanomaterials can lead to power sources for portable, flexible, foldable, and distributable electronics; electric transportation; and grid-scale storage, as well as integration in living environments and biomedical systems. To overcome limitations of nanomaterials related to high reactivity and chemical instability caused by their high surface area, nanoparticles with different functionalities should be combined in smart architectures on nano- and microscales. The integration of nanomaterials into functional architectures and devices requires the development of advanced manufacturing approaches. We discuss successful strategies and outline a roadmap for the exploitation of nanomaterials for enabling future energy storage applications, such as powering distributed sensor networks and flexible and wearable electronics.

We have prepared a membrane electrode assembly (MEA) consisting of Au nano particles (AuNPs) dispersed on Ketjen black (a carbon conductor: C) and Nafion (a proton conductor) as a cathode catalyst and IrO.sub.2 as an anode catalyst for electrocatalytic CO.sub.2 reduction in a gas diffusion electrodes cell. With using lysine as a capping agency, we have succeeded to make MEA first time. MEA with the area of 1 cm.sup.2 showed good performance in electrocatalytic CO.sub.2 reduction giving the CO production rate of 78.5 mol/h with a Faraday efficiency of 81.3% and a current density of 5.2 mA/cm.sup.2 at maximum under the cell voltage of -2.2 V. The particle sizes of synthesized Au-NPs were divided into two groups of around 30 nm and a few nm. The formation of the latter was assisted by the capping effect of lysine and enhanced the electrocatalytic activity. However, at the present condition for AuNPs synthesis, appearance of 50 nm sized particles was unavoidable. Suppression of their formation would significantly enhance the catalytic activity and the present type of membrane assembly has great potential for a practical use.