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External Device (external + device)
Selected AbstractsPercutaneous Lead Implantation Connected to an External Device in Stimulation-Dependent Patients with Systemic Infection,A Prospective and Controlled StudyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2006MARTIN U. BRAUN Background: Permanent pacemaker implantation usually is contraindicated in patients with systemic infection. The aim of the present study was to compare two different techniques of transvenous temporary pacing to bridge the infectious situation until permanent pacemaker implantation under infection-free conditions is possible. Methods and Results: Forty-nine patients with systemic infection and hemodynamic-relevant bradyarrhythmia/asystole were temporarily paced using either a conventional pacing wire/catheter (n = 26, reference group) or a permanent bipolar active pacing lead, which was placed transcutaneously in the right ventricle and connected to an external pacing generator (n = 23, external lead group). In both groups, there were no significant differences in patient characteristics. Whereas the sensing values were almost identical, the median pacing threshold was significantly higher in the reference group (1.0 V vs 0.6 V, P < 0.05). Within comparable duration of pacing (median: 8.2 vs 7.7 days), there were 24 pacing-related adverse events (including dislocation, resuscitation due to severe bradycardia, or local infection) in the reference group as compared to one event in the external lead group (P < 0.01). None of these complications resulted in cardiac death. Conclusion: Thus, transvenous pacing with active fixation is safe and associated with a significantly lower rate of pacing-related adverse events as compared to the standard technique of transvenous pacing using a passive external pacing catheter. [source] Continuous subcutaneous insulin infusion (CSII) 30 years later: still the best option for insulin therapyDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 2 2009Daniela Bruttomesso Abstract Thirty years after its introduction, the use of continuous subcutaneous insulin infusion (CSII) keeps increasing, especially among children and adolescents. The technique, when used properly, is safe and effective. Compared with traditional NPH-based multiple daily injections (MDI), CSII provides a small but clinically important reduction of HbA1c levels, diminishes blood glucose variability, decreases severe hypoglycaemic episodes and offers a better way to cope with the dawn phenomenon. Insulin analogues have improved the treatment of diabetes, eroding part of the place previously occupied by CSII, but CSII still remains the first option for patients experiencing severe hypoglycaemic episodes, high HbA1c values or marked glucose variability while being treated with optimized MDI. Furthermore CSII is better than MDI considering the effects on quality of life and the possibility to adjust insulin administration according to physical activity or food intake. CSII may be limited by cost. Present estimates suggest that CSII may be cost-effective just for patients experiencing a marked improvement in HbA1c or a decrease in severe hypoglycaemic episodes, but the effects on quality of life are difficult to measure. CSII does not merely imply wearing an external device; it requires a multidisciplinary team, intensive patient education and continuous follow up. Copyright © 2009 John Wiley & Sons, Ltd. [source] Clock synchronization for packet networks using a weighted least-squares error filtering technique and enabling circuit emulation serviceINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2007James Aweya Abstract Circuit emulation service (CES) allows time-division multiplexing (TDM) services (T1/E1 and T3/E3 circuits) to be transparently extended across a packet network. With circuit emulation over IP, for instance, TDM data received from an external device at the edge of an IP network is converted to IP packets, sent through the IP network, passed out of the IP network to its destination, and reassembled into TDM bit stream. Clock synchronization is very important for CES. This paper presents a clock synchronization scheme based on a double exponential filtering technique and a linear process model. The linear process model is used to describe the behaviour of clock synchronization errors between a transmitter and a receiver. In the clock synchronization scheme, the transmitter periodically sends explicit time indications or timestamps to a receiver to enable the receiver to synchronize its local clock to the transmitter's clock. A phase-locked loop (PLL) at the receiver processes the transmitted timestamps to generate timing signal for the receiver. The PLL has a simple implementation and provides both fast responsiveness (i.e. fast acquisition of transmitter frequency at a receiver) and significant jitter reduction in the locked state. Copyright © 2006 John Wiley & Sons, Ltd. [source] Toward an Implantable Wireless Cardiac Monitoring Platform Integrated with an FDA-Approved Cardiovascular StentJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2009ERIC Y. CHOW Ph.D. Continuous monitoring of blood pressure from a minimally invasive device in the pulmonary artery can serve as a diagnostic and early warning system for cardiac health. The foremost challenge in such a device is the wireless transfer of data and power from within the blood vessel to an external device while maintaining unrestricted flow through the artery. We present a miniaturized system, which is attached to the outer surface of a regular or drug-eluting FDA-approved stent. When expanded, the stent maintains a patent vessel lumen while allowing contact between the electronic sensors and the blood supply. The stent-based antenna can be used for both wireless telemetry and power transfer for the implanted electronics. Using the stent platform as both a radiating antenna and a structural support allows us to take advantage of an FDA-approved device whose safety and surgical procedure are well established. The electronics package has been reduced to an area of less than 1 mm2, with a thickness under 300 ,m. A minimally invasive implantation procedure allows the delivery of the stent-based implant in nearly any major vessel of the body. This article describes an initial prototype with two stents configured as a single dipole, a 2.4-GHz transmitter microchip, and a battery, and validates transcutaneous transmission through ex vivo and in vivo porcine studies. The results demonstrate the feasibility of a stent-based wireless platform for continuous monitoring of blood pressure. [source] STIFFNESS OF COMPRESSION TESTING MACHINESJOURNAL OF TEXTURE STUDIES, Issue 2 2000HARALD ROHM ABSTRACT A ring test with six participating laboratories and rubber stoppers as reference material was performed to monitor the performance of commercial compression testing instruments. Testing conditions were chosen to be in the range of regular compression testing. Small, single screw instruments with a cantilever exhibited a significant deviation in the force/deformation-response compared with double-screw instruments with a crosshead. Additional tests made with an external device for displacement recording revealed that these differences have to be attributed to insufficient stiffness and some compliance in the cantilever of the tested single-screw instruments. Some consequences of the test results for experiments on soft, semi-soft and rigid food materials are discussed and an equation is developed to correct for the flexing of the cantilever beam in the single screw machine. [source] Does stretching induce lasting increases in joint ROM?PHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 1 2002A systematic review Abstract Background and Purpose Stretching (that is, interventions that apply tension to soft tissues) induces increases in the extensibility of soft tissues, and is therefore widely administered to increase joint mobility and reverse contractures. However, it is not clear whether the effects of stretching are lasting. A systematic review was conducted to determine if stretching (either self-administered, administered manually by therapists or by some external device such as a splint) produces lasting increases in the mobility of joints not directly affected by surgery, trauma or disease processes. Method In order to determine the lasting effects of stretching, only studies that measured joint range of motion (ROM) at least one day after the cessation of stretching were included. MEDLINE (from 1966 to June 2000), EMBASE (from 1988 to June 2000), the Cochrane Controlled Trials Register and PEDro databases were searched, and citation tracking was used to identify randomized studies that met the inclusion criteria. Each study was rated by two independent assessors on the PEDro scale, which rated trials according to criteria such as concealed allocation, blinding and intention-to-treat analysis. Results Thirteen studies satisfied the inclusion criteria. All examined the effect of stretching (median number of stretch sessions = eight) on joint ROM in healthy subjects without functionally significant contractures. Four studies were of ,moderate' quality and the remaining nine were of ,poor' quality. The ,moderate' quality studies suggest that regular stretching increases joint ROM (mean increase in ROM = 8°;95% CI 6° to 9°) for more than one day after cessation of stretching and possibly that the effects of stretching are greater in muscle groups with limited extensibility. Conclusions The results of four ,moderate' quality studies show a convincing effect of stretching in people without functionally significant contracture. These findings require verification with high-quality studies. Lasting effects of intensive stretching programmes (for example, stretching applied for more than six weeks or for more than 20 minutes a day) or of stretching on people with functionally significant contracture have not yet been investigated with randomized studies. Copyright © 2002 Whurr Publishers Ltd. [source] Clinical Practice of Functional Electrical Stimulation: From "Yesterday" to "Today"ARTIFICIAL ORGANS, Issue 8 2008Milan R. DimitrijevicArticle first published online: 18 AUG 200 Abstract:, Functional electrical stimulation (FES) is an accepted treatment method for paresis or paralysis after spinal cord and head injury as well as stroke and other neurological upper motor neuron disorders. At the beginning, FES worked like an electrophysiological brace for the correction of drop foot of patients after a stroke. When analyzing early accomplishments, it becomes evident that FES was influenced rather by technological and biomedical engineering development than by contemporary knowledge on neurocontrol of movement in individuals with upper motor neuron paralysis. Nevertheless, with better understanding of pathophysiology of spasticity and neurocontrol of impaired movement, FES advanced from an electrophysiological brace to a treatment modality for the improvement of muscle control, neuroaugmentation of residual movements, and supportive procedure for "spontaneous recovery" of motor control. In the present article we shall illustrate barriers which delayed FES to be applied in clinical practice of neuron rehabilitation from "Yesterday" to "Today." We shall discuss the importance to apply FES early after the onset of neurological conditions to prevent disuse of noninjured portions of the CNS. Moreover, FES can play a significant role in the supporting processes of neuroplasticity in the subacute phase of upper motor neuron dysfunction. Therefore, the electrophysiological brace of "Yesterday" provides "Today" a correction of missing neuromuscular function. At the same time, it is an active external device for the correction of motor deficits interacting with the somatosensory-motor integration. Thus, "Yesterday" and "Today" of the same technological approach can be very different, thanks to a different understanding and assessment of "external" and "internal" components of human motor control. [source] Covert attention allows for continuous control of brain,computer interfacesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2010Ali Bahramisharif Abstract While brain-computer interfaces (BCIs) can be used for controlling external devices, they also hold the promise of providing a new tool for studying the working brain. In this study we investigated whether modulations of brain activity by changes in covert attention can be used as a continuous control signal for BCI. Covert attention is the act of mentally focusing on a peripheral sensory stimulus without changing gaze direction. The ongoing brain activity was recorded using magnetoencephalography in subjects as they covertly attended to a moving cue while maintaining fixation. Based on posterior alpha power alone, the direction to which subjects were attending could be recovered using circular regression. Results show that the angle of attention could be predicted with a mean absolute deviation of 51° in our best subject. Averaged over subjects, the mean deviation was ,70°. In terms of information transfer rate, the optimal data length used for recovering the direction of attention was found to be 1700 ms; this resulted in a mean absolute deviation of 60° for the best subject. The results were obtained without any subject-specific feature selection and did not require prior subject training. Our findings demonstrate that modulations of posterior alpha activity due to the direction of covert attention has potential as a control signal for continuous control in a BCI setting. Our approach will have several applications, including a brain-controlled computer mouse and improved methods for neuro-feedback that allow direct training of subjects' ability to modulate posterior alpha activity. [source] Breaking the silence: Brain,computer interfaces (BCI) for communication and motor controlPSYCHOPHYSIOLOGY, Issue 6 2006Niels Birbaumer Abstract Brain,computer interfaces (BCI) allow control of computers or external devices with regulation of brain activity alone. Invasive BCIs, almost exclusively investigated in animal models using implanted electrodes in brain tissue, and noninvasive BCIs using electrophysiological recordings in humans are described. Clinical applications were reserved with few exceptions for the noninvasive approach: communication with the completely paralyzed and locked-in syndrome with slow cortical potentials, sensorimotor rhythm and P300, and restoration of movement and cortical reorganization in high spinal cord lesions and chronic stroke. It was demonstrated that noninvasive EEG-based BCIs allow brain-derived communication in paralyzed and locked-in patients but not in completely locked-in patients. At present no firm conclusion about the clinical utility of BCI for the control of voluntary movement can be made. Invasive multielectrode BCIs in otherwise healthy animals allowed execution of reaching, grasping, and force variations based on spike patterns and extracellular field potentials. The newly developed fMRI-BCIs and NIRS-BCIs, like EEG BCIs, offer promise for the learned regulation of emotional disorders and also disorders of young children. [source] | ||||||||||