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At least 37 records · Page 2Linked to original sources

PubMedDate not supplied

Initial clinical experience with a wearable controller for the Novacor left ventricular assist system.

The Novacor left ventricular assist system (LVAS), an implanted electromechanically driven blood pump, has been used in an ongoing clinical trial as a bridge to cardiac transplantation since 1984. The initial configuration included a console based extracorporeal controller. Because patients supported by the device usually become rehabilitated and highly mobile, a wearable control system was developed for the ambulatory patient. Ergonomically designed for portability, comfort, and appearance, it offers the recipient greater mobility, improved self-image, and an enhanced quality of life. This wearable control system consists of a microprocessor based compact controller that drives the implanted pump/drive unit in synchronous counterpulsation to the native heart. Main and reserve rechargeable power packs, each incorporating a "smart" monitoring circuit with charge-level display and alarm, are capable of supporting the pump for as long as 7 hr. An LVAS monitor can be connected to the controller for device monitoring and adjustment or as a power supply in lieu of the main power pack. Clinical evaluation in patients with end-stage heart disease followed the same protocol as the console study. By April 4, 1994, 41 patients had been supported by the wearable system, including 9 patients currently being supported. Mean duration of use was 51 days (range, 1.5-143+ days), compared with 42 days for 170 console patients (range, 0-370 days). Survival to transplant was 66%, which was similar to the survival (60%) for the patients using the console. Post-transplant survival was 100%, compared with 90% for console patients (not significantly different). After recovering from implant surgery and pre-implant morbidity, device recipients had considerable freedom and mobility and were able to move freely within and outside the hospital. Recipients could readily switch between monitored and untethered operation and could manage power pack replacement and recharging.

Adult↗

PubMed2005

An ultrasound wearable system for the monitoring and acceleration of fracture healing in long bones.

An ultrasound wearable system for remote monitoring and acceleration of the healing process in fractured long bones is presented. The so-called USBone system consists of a pair of ultrasound transducers, implanted into the fracture region, a wearable device and a centralized unit. The wearable device is responsible to carry out ultrasound measurements using the axial-transmission technique and initiate therapy sessions of low-intensity pulsed ultrasound. The acquired measurements and other data are wirelessly transferred from the patient-site to the centralized unit, which is located in a clinical setting. The evaluation of the system on an animal tibial osteotomy model is also presented. A dataset was constructed for monitoring purposes consisting of serial ultrasound measurements, follow-up radiographs, quantitative computed tomography-based densitometry and biomechanical data. The animal study demonstrated the ability of the system to collect ultrasound measurements in an effective and reliable fashion and participating orthopaedic surgeons accepted the system for future clinical application. Analysis of the acquired measurements showed that the pattern of evolution of the ultrasound velocity through healing bones over the postoperative period monitors a dynamic healing process. Furthermore, the ultrasound velocity of radiographically healed bones returns to 80% of the intact bone value, whereas the correlation coefficient of the velocity with the material and mechanical properties of the healing bone ranges from 0.699 to 0.814. The USBone system constitutes the first telemedicine system for the out-hospital management of patients sustained open fractures and treated with external fixation devices.

Animals↗

PubMed2005

A multiparameter wearable physiologic monitoring system for space and terrestrial applications.

A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of acceleration, and blood pressure. These parameters can be digitally recorded with high fidelity over a 9-h period with precise time stamps and user-defined event markers. Data can be continuously streamed to a base station using a built-in Bluetooth RF link or stored in 32 MB of on-board flash memory and downloaded to a personal computer using a serial port. The device is powered by two AAA batteries. The design, laboratory, and field testing of the wearable monitors are described.

Aerospace Medicine↗

PubMed2004

An intelligent service-based network architecture for wearable robots.

We are developing a novel robot concept called the wearable robot. Wearable robots are mobile information devices capable of supporting remote communication and intelligent interaction between networked entities. In this paper, we explore the possible functions of such a robotic network and will present a distributed network architecture based on service components. In order to support the interaction and communication between the components in the wearable robot system, we have developed an intelligent network architecture. This service-based architecture involves three major mechanisms. The first mechanism involves the use of a task coordinator service such that the execution of the services can be managed using a priority queue. The second mechanism enables the system to automatically push the required service proxy to the client intelligently based on certain system-related conditions. In the third mechanism, we allow the system to automatically deliver services based on contextual information. Using a fuzzy-logic-based decision making system, the matching service can determine whether the service should be automatically delivered utilizing the information provided by the service, client, lookup service, and context sensors. An application scenario has been implemented to demonstrate the feasibility of this distributed service-based robot architecture. The architecture is implemented as extensions to the Jini network model.

Algorithms↗

PubMed1992

Wearable air supply for pneumatic artificial hearts and ventricular assist devices.

An experimental wearable air supply for pneumatic artificial hearts and ventricular assist devices has been built and tested. The unit eliminates the need for tethering to a large, stationery driver. The miniaturized air supply is designed for ambulatory patients with implanted pulsatile pneumatic total artificial hearts (TAH) or pneumatic left-ventricular assist devices (LVAD), to permit mobility in clinical and home settings. The device has major short-term utility as a supply for pneumatic TAH or VAD bridges in patients awaiting heart transplants. The system design for the wearable driver includes a novel, fast rotary compressor, driven by a brushless direct current (DC) motor to supply air to the ventricle through an electromagnetically actuated directional valve, all controlled by a microcomputer. Stroke volume from 0 to 200 cc; pulse rate from 60 to 160 bpm, and duty cycle from 33% to 50% are selected on a keyboard, and the selected or measured parameters can be shown on a liquid crystal display. For control of delivery from a single ventricular assist device, stroke volume is controlled by variation of compressor speed. In the wearable air supply for a TAH, a single compressor drives both ventricles alternately through a double-acting directional valve. Air volume delivered to the left ventricle is adjusted by variation of compressor speed, and air volume to the right ventricle by variation of ejection time. The effect on blood flow rate of the lower impedance to the right ventricle is compensated by provision of a two-stage compressor, in which a single stage drives the right ventricle, and both stages connected in parallel drive the left ventricle. The overall dimensions of the prototype air supply for driving either a TAH or LVAD are 4.5 by 7.8 by 4.5 inches, including an emergency battery with a duration of 15 to 30 min depending on load. The weight is presently 5.5 lb, but this will be reduced in a production design and for a dedicated LVAD air supply. The size and weight of a separately worn, rechargeable battery pack depend on the load and desired duration of operation.

Electric Power Supplies↗

PubMed2006

Influences of palatal side design and finishing on the wearability and retention of mouthguards.

OBJECTIVES: To examine the influences of design and finishing on mouthguard wearability and retention. MATERIALS AND METHODS: 17 students at the Dental Technician Institute at Osaka University School of Dentistry, Osaka, Japan, participated in this study after providing informed consent. For each student, a single-layer custom-made mouthguard was fabricated from a 3.8-mm-thick ethylene-vinyl acetate sheet using a standardised procedure to obtain a precise fit. Each mouthguard was modified by changing the margin location and shape through five consecutive steps. At each step, questionnaires with a visual analogue scale regarding wearability (comfort, breathing, speaking, swallowing, lip closure, temporomandibular joint fatigue and swallowing) and retention were completed by subjects after wearing the mouthguard for 5 min. Statistical analyses were carried out among the steps using Wilcoxon's signed-rank test with a significance level of p<0.05. RESULTS: Significant improvements were found for comfort, breathing, speaking and swallowing by trimming the palatal margin to the cervical area, smooth finishing and occlusal adjustment of the mouthguard (p<0.01). No significant differences were found for retention throughout the procedure. CONCLUSIONS: Within the limitations of this experimental study, design and finishing at the palatal side appear to have significant influences on mouthguard wearability, but not retention.

Adult↗

PubMed2005

Initial development and testing of a novel foam-based pressure sensor for wearable sensing.

BACKGROUND: This paper provides an overview of initial research conducted in the development of pressure-sensitive foam and its application in wearable sensing. The foam sensor is composed of polypyrrole-coated polyurethane foam, which exhibits a piezo-resistive reaction when exposed to electrical current. The use of this polymer-coated foam is attractive for wearable sensing due to the sensor's retention of desirable mechanical properties similar to those exhibited by textile structures. METHODS: The development of the foam sensor is described, as well as the development of a prototype sensing garment with sensors in several areas on the torso to measure breathing, shoulder movement, neck movement, and scapula pressure. Sensor properties were characterized, and data from pilot tests was examined visually. RESULTS: The foam exhibits a positive linear conductance response to increased pressure. Torso tests show that it responds in a predictable and measurable manner to breathing, shoulder movement, neck movement, and scapula pressure. CONCLUSION: The polypyrrole foam shows considerable promise as a sensor for medical, wearable, and ubiquitous computing applications. Further investigation of the foam's consistency of response, durability over time, and specificity of response is necessary.

Journal Article↗

PubMed2005

Wearable Conductive Fiber Sensors for Multi-Axis Human Joint Angle Measurements.

BACKGROUND: The practice of continuous, long-term monitoring of human joint motion is one that finds many applications, especially in the medical and rehabilitation fields. There is a lack of acceptable devices available to perform such measurements in the field in a reliable and non-intrusive way over a long period of time. The purpose of this study was therefore to develop such a wearable joint monitoring sensor capable of continuous, day-to-day monitoring. METHODS: A novel technique of incorporating conductive fibers into flexible, skin-tight fabrics surrounding a joint is developed. Resistance changes across these conductive fibers are measured, and directly related to specific single or multi-axis joint angles through the use of a non-linear predictor after an initial, one-time calibration. Because these sensors are intended for multiple uses, an automated registration algorithm has been devised using a sensitivity template matched to an array of sensors spanning the joints of interest. In this way, a sensor array can be taken off and put back on an individual for multiple uses, with the sensors automatically calibrating themselves each time. RESULTS: The wearable sensors designed are comfortable, and acceptable for long-term wear in everyday settings. Results have shown the feasibility of this type of sensor, with accurate measurements of joint motion for both a single-axis knee joint and a double axis hip joint when compared to a standard goniometer used to measure joint angles. Self-registration of the sensors was found to be possible with only a few simple motions by the patient. CONCLUSION: After preliminary experiments involving a pants sensing garment for lower body monitoring, it has been seen that this methodology is effective for monitoring joint motion of the hip and knee. This design therefore produces a robust, comfortable, truly wearable joint monitoring device.

Journal Article↗

PubMed1984

Closed-loop glycemic control with a wearable artificial endocrine pancreas. Variations in daily insulin requirements to glycemic response.

We succeeded in miniaturizing a needle-type glucose monitoring system with characteristics suitable for application in a wearable, closed-loop control system. A wearable artificial endocrine pancreas (12 X 15 X 6 cm, 400 g) consisting of a sensor, a microcomputer system that calculates insulin and glucagon infusion rates, and two roller pumps was developed. Continuous glucose monitoring by a glucose sensor inserted in the subcutaneous tissue of the forearm or abdomen of healthy and diabetic volunteers revealed that glucose concentrations in subcutaneous tissue were 10% lower than, but were highly correlated with, blood glucose concentrations in the range of 49-388 mg/dl. Glycemic control was established in diabetic patients by intravenously infusing insulin in response to measured glucose concentrations on a moment-to-moment basis for a period of several days. By comparing the glycemic control obtained in each patient treated with multiple insulin injections or open-loop subcutaneous insulin infusion, the superiority of feedback control with the system was clearly demonstrated. During continuous glycemic regulation, day-to-day variations of insulin requirements were recognized in both basal insulin infusion and postprandial insulin infusion rates in response to identical meals and exercise. These data suggest the feasibility of long-term glycemic control in diabetic subjects with a wearable artificial endocrine pancreas, and indicate that to overcome changes in individual metabolic characteristics on a moment-to-moment basis, a closed-loop glycemic control system may be essential for ambulatory diabetic patients.

Adult↗

PubMed1999

The Wearable Motherboard: a flexible information infrastructure or sensate liner for medical applications.

Research on the design and development of a Sensate Liner for Combat Casualty Care has led to the realization of the world's first Wearable Motherboard or an "intelligent" garment for the 21st Century. This Georgia Tech Wearable Motherboard (GTWM) provides an extremely versatile framework for the incorporation of sensing, monitoring and information processing devices. The principal advantage of GTWM is that it provides, for the first time, a very systematic way of monitoring the vital signs of humans in an unobtrusive manner. Appropriate sensors have been "plugged" into this motherboard using the developed Interconnection Technology and attached to any part of the individual being monitored, thereby creating a flexible wearable monitoring device. The flexible data bus integrated into the structure transmits the information to monitoring devices such as an EKG Machine, a temperature recorder, a voice recorder, etc. The bus also serves to transmit information to the sensors (and hence, the wearer) from external sources, thus making GTWM a valuable information infrastructure. GTWM is lightweight and can be worn easily by anyone--from infants to senior citizens. GTWM has enormous potential for applications in fields such as telemedicine, monitoring of patients in post-operative recovery, the prevention of SIDS (sudden infant death syndrome), and monitoring of astronauts, athletes, law enforcement personnel and combat soldiers.

Ambulatory Care↗

PubMed2004

Research and development of smart wearable health applications: the challenge ahead.

Continuous monitoring of physiological and physical parameters is necessary for the assessment and management of personal health status. It can significantly contribute to the reduction of healthcare cost by avoiding unnecessary hospitalisations and ensuring that those who need urgent care get it sooner. In conjunction with cost-effective telemedicine platforms, ubiquitous health monitoring can significantly contribute to the enhancement of disease prevention and early diagnosis, disease management, treatment and home rehabilitation. Latest developments in the area of micro and nanotechnologies, information processing and wireless communication offer, today, the possibility for minimally (or non) invasive biomedical measurement but also wearable sensing, processing and data communication. Although the systems are being developed to satisfy specific user needs, a number of common critical issues have to be tackled to achieve reliable and acceptable smart health wearable applications e.g. biomedical sensors, user interface, clinical validation, data security and confidentiality, scenarios of use, decision support, user acceptance and business models. Major technological achievements have been realised the last few years. Cutting edge development combining functional clothing and integrated electronics open a new research area and possibilities for body sensing and communicating health parameters. This paper reviews the current status of research and development on smart wearable health systems and applications and discusses the outstanding issues and future challenges.

Consumer Behavior↗

PubMedDate not supplied

Development and evaluation of a wearable blood glucose monitor.

Complex operation, prolonged set-up time, reliability problems, high cost, and excessive size limits the use of currently available extracorporeal continuous blood glucose analyzers. A self-calibrating, wearable blood glucose monitor has been developed to overcome these impediments. The wearable blood glucose monitor is a 410 g forearm-mounted instrument with three miniature pumps for blood sampling, calibration, and insulin infusion, and a flow cell containing an enzyme-electrode sensor capable of determining plasma glucose levels accurately and precisely in undiluted whole blood. The unit is connected to a computer controller with graphics display. Venous blood is drawn from a 21 gauge single lumen cannula through the sensor flow cell. A rate determination of glucose is completed in 20 sec and the blood is returned to the arm vein. Heparinized saline wash solution follows. No blood loss or significant systemic heparinization occurs. Cycle time is set from 2 to 5 min. The method is linear to at least 300 mg/dl glucose, independent of hematocrit, and free of interferences from blood constituents at normal venous pO2 with a coefficient of variation of 1-3% between calibrations. The sensor has a service life of at least 3 weeks. This wearable blood glucose monitor, with its high performance sensor, reduced size, and ease of operation, shows promise for evaluating and treating diabetes.

Animals↗

PubMed1984

The development of wearable-type artificial endocrine pancreas and its usefulness in glycaemic control of human diabetes mellitus.

We have succeeded in miniaturizing a glucose monitoring system into a needle-type which preserves the characteristics suitable for application in a wearable closed-loop control system. The wearable artificial endocrine pancreas (12 X 15 X 6 cm, 400 g) consists of the sensor, a microcomputer which calculates the insulin and glucagon infusion rates and of a 2-syringe driving system. The device succeeded in controlling glycaemia perfectly in depancreatized dogs for a period of 3 days, and with replacement of subcutaneously inserted sensor for up to 7 days. When glucose monitoring by a needle-type glucose sensor inserted into subcutaneous tissue of the forearm or abdomen of healthy and diabetic volunteers was attempted, the readings were about 10% lower than blood glucose concentrations, but good correlation between them was observed in the range of 60 to 400 mg/dl. Perfect glycaemic control was established by infusing insulin either intravenously or subcutaneously in response to measured glucose concentrations on a moment-to-moment basis in diabetics for a period of several days. These results might indicate the feasibility of long-term glycaemic control in ambulatory diabetic patients with a wearable closed-loop glycaemic control system.

Blood Glucose↗

PubMed2026

Wearable wrist-watch type cuff oscillometric blood pressure monitors: consensus statement by the European Society of Hypertension Working Group on blood pressure monitoring.

Wearable wristwatch-type cuff oscillometric blood pressure (BP) monitors represent a new category of BP devices and are the first wearable monitors to use established cuff-oscillometric BP measurement technology. This consensus statement by the European Society of Hypertension Working Group on BP Monitoring reviews the published evidence on their design, accuracy, validation, clinical application, and remaining research questions. Of 281 articles identified through a systematic PubMed search, 26 were relevant. Several devices are currently available; however, only two have published validation studies performed according to established standards (Omron HeartGuide and Huawei Watch D/D2). Static validation studies generally showed acceptable accuracy, whereas data on 24-h ambulatory use, in special populations, and clinical applications remain limited. Potential advantages include self-initiated measurement at home, at work, and in other settings and conditions; more convenient and repeatable 24-h ambulatory monitoring; more convenient and accurate assessment of asleep BP; capture of stress-related and other BP-related episodes. However, proper wrist position, user adherence, ambulatory performance, and clinical applications require further investigation. More research is needed to establish the accuracy and clinical utility of these novel devices and their role in improving the diagnosis and management of hypertension.

Humans↗

PubMed2006

Development and testing of a wearable Integrated Thermometer sensor for skin contact thermography.

The need of wearable devices for the thermal monitoring is rising. These devices could be used during medical continuous monitoring, for instance in breast cancer investigation, or for the monitoring of vascular, dermatological and rheumatic disorders, in viability studies, and during physical exercises. We had designed and constructed a wearable device for skin-contact thermography that uses integrated silicon sensors. The bench test validation was performed by means of a commercial oven for the static bench test and a properly designed phantom for the dynamic bench test. The thermal resolution was better than 0.03 degrees C and the spatial resolution equal to 1.6 x 10(-5)m2. We then investigated its performance in a medical application, suited for clinical testing, in which volunteers were subject to a maximal rate of thermal skin variation equal to 3.1 degrees C/0.25 h. We also compared the results with those obtained by means of an Infrared-Digital-Video-Camera. Results of the comparison showed a maximal error always lower than 0.14 degrees C.

Equipment Design↗

PubMed1995

Bridge to transplantation with the wearable Novacor left ventricular assist system: operative technique.

Although the outcome of patients transplanted after univentricular cardiac support is similar to that of conventional patients, death on the device remains a substantial problem. The wearable Novacor left ventricular assist system (LVAS) may offer advantages over console-based systems by improving rehabilitation before transplantation. For these advantages to be realised, however, a smooth perioperative course is necessary. We describe our operative technique, based on minimising blood loss and preserving right ventricular function, and the results in the first three patients to have the wearable Novacor LVAS implanted in this institution.

Cardiac Surgical Procedures↗

PubMed1985

A microcomputer-based wearable biofeedback device to improve transfer of treatment in parkinsonian dysarthria.

Achieving transfer of treatment outside the clinic is a problem for almost all individuals with speech disorders but has been particularly difficult in the treatment of patients with Parkinsonism. Given this situation and the frequency of vocal intensity problems in this population, we developed a wearable biofeedback device that could provide a patient with information about speech intensity outside the clinic. Auditory-perceptual and acoustic analyses were performed on audiotaped samples of reading and spontaneous speech recorded in the clinic pre- and posttreatment and at 10- and 20-week follow-ups. Visual feedback of intensity was integrated with auditory cues from a microcomputer that was then worn outside the clinic. The results indicated that the subject did transfer a substantial portion of clinic improvement to the outside environment while wearing the feedback device and suggest the utility of a microcomputer-based wearable device for assessing treatment effects as well as for improving transfer.

Aged↗

PubMed1998

Enhanced, simplified glucose sensors: long-term clinical application of wearable artificial endocrine pancreas.

At present, 2 major problems should be solved before long-term application of the wearable artificial endocrine pancreas, the development of a reliable and stable glucose monitoring system and the development of a subcutaneous insulin infusion algorithm. With either a miniaturized extracorporeal glucose monitoring system based on microdialysis sampling method or a ferrocene-mediated needle-type glucose sensor covered with highly biocompatible membrane, poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (poly[MPC-co-BMA]) membrane, subcutaneous glucose concentrations could be monitored for 7 days without any in vivo calibrations, followed by 14 days with one point calibration. Considering the management and safety of the insulin delivery route, subcutaneous insulin infusion is obligatory. With the subcutaneous insulin infusion algorithm using a short acting insulin analogue (Insulin Lispro), near physiological glycemic control could be established in diabetic patients without showing any delayed hyperinsulinemia or hypoglycemia. The wearable artificial endocrine pancreas is now recognized as an excellent therapeutic tool for regulating blood glucose excursions physiologically in ambulatory diabetic patients on a long-term basis.

Animals↗