| 1. |
- Gund, Anna, 1980, et al.
(author)
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Design Evaluation of a Home-Based Telecare System for Chronic Heart Failure Patients
- 2008
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In: Engineering in Medicine and Biology Society, 2008. EMBS 2008. 30th Annual International Conference of the IEEE. - : IEEE. - 1557-170X. - 9781424418145 ; , s. 5851-5854, s. 5851-5854
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Conference paper (peer-reviewed)abstract
- In order to improve the care of Chronic Heart Failure (CHF) patients, a system has been developed for monitoring symptoms and document subjective judgments on health conditions in a home environment. Since system usability is an important issue, a two step evaluation of the solution was conducted. First a ten-patient survey was conducted, which was aimed at spotting possible problem areas. The second step involved a small trial in a home setting with CHF patients. The results are promising, indicating that the system is user friendly and easy to use, and that it is suitable as a prototype for the intended use.
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| 2. |
- Wiklund, Urban, et al.
(author)
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Adaptive spatio-temporal filtering of disturbed ECGs: a multi-channel approach to heartbeat detection in smart clothing
- 2007
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In: Medical and Biological Engineering and Computing. - : Springer Science and Business Media LLC. - 1741-0444 .- 0140-0118. ; 45:6, s. 515-523
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Journal article (peer-reviewed)abstract
- Intermittent disturbances are common in ECG signals recorded with smart clothing: this is mainly because of displacement of the electrodes over the skin. We evaluated a novel adaptive method for spatio-temporal filtering for heartbeat detection in noisy multi-channel ECGs including short signal interruptions in single channels. Using multi-channel database recordings (12-channel ECGs from 10 healthy subjects), the results showed that multi-channel spatio-temporal filtering outperformed regular independent component analysis. We also recorded seven channels of ECG using a T-shirt with textile electrodes. Ten healthy subjects performed different sequences during a 10-min recording: resting, standing, flexing breast muscles, walking and pushups. Using adaptive multi-channel filtering, the sensitivity and precision was above 97% in nine subjects. Adaptive multi-channel spatio-temporal filtering can be used to detect heartbeats in ECGs with high noise levels. One application is heartbeat detection in noisy ECG recordings obtained by integrated textile electrodes in smart clothing.
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| 3. |
- Ferreira, Javier, 1982-, et al.
(author)
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A handheld and textile-enabled bioimpedance system for ubiquitous body composition analysis. : An initial functional validation
- 2016
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In: IEEE journal of biomedical and health informatics. - : Institute of Electrical and Electronics Engineers (IEEE). - 2168-2194 .- 2168-2208. ; 21:5
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Journal article (peer-reviewed)abstract
- In recent years, many efforts have been made to promote a healthcare paradigm shift from the traditional reactive hospital-centered healthcare approach towards a proactive, patient-oriented and self-managed approach that could improve service quality and help reduce costs while contributing to sustainability. Managing and caring for patients with chronic diseases accounts over 75% of healthcare costs in developed countries. One of the most resource demanding diseases is chronic kidney disease (CKD), which often leads to a gradual and irreparable loss of renal function, with up to 12% of the population showing signs of different stages of this disease. Peritoneal dialysis and home haemodialysis are life-saving home-based renal replacement treatments that, compared to conventional in-center hemodialysis, provide similar long-term patient survival, less restrictions of life-style, such as a more flexible diet, and better flexibility in terms of treatment options and locations. Bioimpedance has been largely used clinically for decades in nutrition for assessing body fluid distributions. Moreover, bioimpedance methods are used to assess the overhydratation state of CKD patients, allowing clinicians to estimate the amount of fluid that should be removed by ultrafiltration. In this work, the initial validation of a handheld bioimpedance system for the assessment of body fluid status that could be used to assist the patient in home-based CKD treatments is presented. The body fluid monitoring system comprises a custom-made handheld tetrapolar bioimpedance spectrometer and a textile-based electrode garment for total body fluid assessment. The system performance was evaluated against the same measurements acquired using a commercial bioimpedance spectrometer for medical use on several voluntary subjects. The analysis of the measurement results and the comparison of the fluid estimations indicated that both devices are equivalent from a measurement performance perspective, allowing for its use on ubiquitous e-healthcare dialysis solutions.
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| 4. |
- Buendia, Ruben, 1982, et al.
(author)
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Estimation of body fluids with bioimpedance spectroscopy: state of the art methods and proposal of novel methods
- 2015
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In: Physiological Measurement. - : IOP Publishing. - 0967-3334 .- 1361-6579. ; 36:10
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Journal article (peer-reviewed)abstract
- Determination of body fluids is a useful common practice in determination of disease mechanisms and treatments. Bioimpedance spectroscopy (BIS) methods are non-invasive, inexpensive and rapid alternatives to reference methods such as tracer dilution. However, they are indirect and their robustness and validity are unclear. In this article, state of the art methods are reviewed, their drawbacks identified and new methods are proposed. All methods were tested on a clinical database of patients receiving growth hormone replacement therapy. Results indicated that most BIS methods are similarly accurate (e.g. < 0.5 +/- 3.0% mean percentage difference for total body water) for estimation of body fluids. A new model for calculation is proposed that performs equally well for all fluid compartments (total body water, extra-and intracellular water). It is suggested that the main source of error in extracellular water estimation is due to anisotropy, in total body water estimation to the uncertainty associated with intracellular resistivity and in determination of intracellular water a combination of both.
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| 5. |
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| 6. |
- Löfhede, Johan, 1978, et al.
(author)
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Automatic classification of background EEG activity in healthy and sick neonates
- 2010
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In: Journal of Neural Engineering. - : IOP Publishing. - 1741-2560 .- 1741-2552. ; 7:1
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Journal article (peer-reviewed)abstract
- The overall aim of our research is to develop methods for a monitoring system to be used at neonatal intensive care units. When monitoring a baby, a range of different types of background activity needs to be considered. In this work, we have developed a scheme for automatic classification of background EEG activity in newborn babies. EEG from six full-term babies who were displaying a burst suppression pattern while suffering from the after-effects of asphyxia during birth was included along with EEG from 20 full-term healthy newborn babies. The signals from the healthy babies were divided into four behavioural states: active awake, quiet awake, active sleep and quiet sleep. By using a number of features extracted from the EEG together with Fisher’s linear discriminant classifier we have managed to achieve 100% correct classification when separating burst suppression EEG from all four healthy EEG types and 93% true positive classification when separating quiet sleep from the other types. The other three sleep stages could not be classified. When the pathological burst suppression pattern was detected, the analysis was taken one step further and the signal was segmented into burst and suppression, allowing clinically relevant parameters such as suppression length and burst suppression ratio to be calculated. The segmentation of the burst suppression EEG works well, with a probability of error around 4%.
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| 7. |
- Seoane, Fernando, 1976-, et al.
(author)
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Electrical Bioimpedance Cerebral Monitoring : A Study of the Current Density Distribution and Impedance Sensitivity Maps on a 3D Realistic Head Model
- 2007
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In: Proceedings of the 3rd IEEE-EMBS International Conference on Neural Engineering. - : IEEE. - 1424407923 ; , s. 256 - 260
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Conference paper (peer-reviewed)abstract
- There have been several studies of the application of electrical bioimpedance technology for brain monitoring in the past years. They have targeted a variety of events and injuries e.g. epilepsy or stroke. The current density distribution and the voltage lead field associated with an impedance measurement setup is of critical importance for the proper analysis of any dynamics in the impedance measurement or for an accurate reconstruction of an EIT image, specially a dynamic type. In this work for the first time, the current density distribution is calculated in a human head with anatomical accuracy and resolution down to 1 mm, containing up to 24 tissues and considering the frequency dependency of the conductivity of each tissue. The obtained current densities and the subsequent sensitivity maps are analyzed with a special focus on the dependency of the electrode arrangement and also the measurement frequency. The obtained results provide us with interesting and relevant information to consider in the design of any tool for electrical bioimpedance cerebral monitoring.
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| 8. |
- Seoane, Fernando, 1976-, et al.
(author)
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Current Source for Wideband Electrical Bioimpedance Spectroscopy Based on a Single Operational Amplifier
- 2006
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In: WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING 2006, VOL 14, PTS 1-6. - : IFMBE. - 9783540368397 ; , s. 707-710
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Conference paper (peer-reviewed)abstract
- Traditionally, measurements of electrical bioimpedance for medical diagnostic purposes have used only low frequencies, usually below 100 kHz. The analysis focused only on the resistive part of the impedance; very often at low frequencies the reactive part of the impedance is negligible. Recent studies of the electrical bioimpedance spectrum, both real and imaginary parts, have indicated new potential applications e.g. detection of meningitis, skin cancer assessment and brain cellular edema detection. An important functional unit in a wideband impedance spectrometer is the current source used to inject the current into the tissue under study. A current source must provide an output current virtually constant over the frequency range of interest and independent of the load at the output. Several designs have been proposed over the years but the performance of them all degraded markedly near bellow 1 MHz e.g. Ackmann in 1993, Bragos et al in 1994 and Bertemes-Filho et al in 2000. The development of electronic technology has made available devices that allow us to obtain a current source with large output impedance, larger than 100 k Omega, above I MHz and based in a simple single Op-Amp circuit topology. Simulation results and experimental measurements are compared and the most important parameters of the VCCS are analytically studied and experimentally tested, including the dependency to changes in the circuit elements and the incidence of the Op-Amp parameters on the current source features.
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| 9. |
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| 10. |
- Thordstein, Magnus, et al.
(author)
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Effects of inflammation on cerebral electric activity in fetal sheep
- 2008
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In: 2nd Congress of the European Academy of Paediatrics, Nice 23-28 okt 2008.
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Conference paper (other academic/artistic)abstract
- OBJECTIVE Intrauterine infections can by themselves induce fetal brain damage but also potentiate the effects of other harmful influences such as asphyxia and seizures. Using an EEG technique that permits the recording of extremely low frequencies, often called DC EEG, changes in the level, i.e. DC shifts can be detected. The DC level has been suggested to depend mainly on the potential over the blood brain barrier (BBB), in turn decided primarily by the arterial level of pCO2. Fetuses affected by infection/inflammation that produce detrimental effects on the brain, may have elevated levels of pCO2 and disturbance of the BBB. We aimed at investigating the possibility that the DC EEG could be used to detect the effects of inflammation on the fetal brain. METHODS Fetal sheep were instrumented at 97 days of gestation with catheters, four active EEG electrodes placed on the dura mater as well as extracranial reference and ground electrodes. After three days of recovery, the bacterial endotoxin lipopolysaccharide (LPS) was given to the fetus (200 ng i.v.). RESULTS Exposure to LPS induced a positive DC shift in parallel to the assumed affection of cerebral function and to the pCO2 elevation. This change was not always obvious in standard EEG. CONCLUSIONS These recordings of fetal DC EEG appear to be the first to be done. They indicate that the effects of inflammation on cerebral function can be monitored by DC EEG. Such monitoring might be feasible also during late stages of labour and in neonates.
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