| 1. |
- Buendia, Ruben, 1982, et al.
(författare)
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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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Ingår i: Physiological Measurement. - : IOP Publishing. - 0967-3334 .- 1361-6579. ; 36:10
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Buendia, Rubén, et al.
(författare)
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Robustness study of the different immittance spectra and frequency ranges in bioimpedance spectroscopy analysis for assessment of total body composition.
- 2014
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Ingår i: Physiological measurement. - : IOP Publishing. - 1361-6579 .- 0967-3334. ; 35:7, s. 1373-95
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Tidskriftsartikel (refereegranskat)abstract
- The estimation of body fluids is a useful and common practice for assessment of disease status and therapy outcomes. Electrical bioimpedance spectroscopy (EBIS) methods are noninvasive, inexpensive and efficient alternatives for determination of body fluids. One of the main source of errors in EBIS measurements in the estimation of body fluids is capacitive coupling. In this paper an analysis of capacitive coupling in EBIS measurements was performed and the robustness of the different immittance spectra against it tested. On simulations the conductance (G) spectrum presented the smallest overall error, among all immittance spectra, in the estimation of the impedance parameters used to estimate body fluids. Afterwards the frequency range of 10-500kHz showed to be the most robust band of the G spectrum. The accuracy of body fluid estimations from the resulting parameters that utilized G spectrum and parameters provided by the measuring device were tested on EBIS clinical measurements from growth hormone replacement therapy patients against estimations performed with dilution methods. Regarding extracellular fluid, the correlation between each EBIS method and dilution was 0.93 with limits of agreement of 1.06 ± 2.95 l for the device, 1.10 ± 2.94 l for G [10-500kHz] and 1.04 ± 2.94 l for G [5-1000kHz]. Regarding intracellular fluid, the correlation between dilution and the device was 0.91, same as for G [10-500kHz] and 0.92 for G [5-1000kHz]. Limits of agreement were 0.12 ± 4.46 l for the device, 0.09 ± 4.45 for G [10-500kHz] and 0.04 ± 4.58 for G [5-1000kHz]. Such close results between the EBIS methods validate the proposed approach of using G spectrum for initial Cole characterization and posterior clinical estimation of body fluids status.
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| 3. |
- Gund, Anna, 1980, et al.
(författare)
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Care@Distance – Disease Management för hjärtsviktspatienter i hemmet
- 2007
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Ingår i: Medicinteknikdagarna, 2-3 October 2007, Örebro, Sweden. - : Svensk förening för medicinsk teknik och fysik, Örebro Läns Landsting, Örebro Universitet, Stiftelsen för strategisk forskning, Vetenskapsrådet, Vinnova.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Antalet äldre i samhället ökar, och med det kostnaderna p.g.a. kroniska åldersrelaterade sjukdomstillstånd. Ett sådant tillstånd är hjärtsvikt vilket drabbar ca 2 % av västvärldens befolkning. Forskning har visat att IT-baserad hemvård för s.k. Disease Management kan resultera i minskade kostnader så väl som ökad livskvalitet hos patienterna. Inom projektet Care@Distance är avsikten att utforma ett sådant system där tyngden ligger dels på regelbundna dagliga enkla mätningar av fysiologiskt relaterade parametrar såsom vikt och blodtryck, och dels på formulär där patienten svarar på några enkla frågor om det upplevda tillståndet. Syftet är att få med både objektiv och subjektiv information som sedan kan ligga till grund för en förbättrad vård av den enskilde patienten. Systemet utformas främst för att skapa underlag för en bättre långsiktig behandling, terapi och för uppföljning av Treatment Compliance, men även för att hantera akuta situationer genom t.ex. larm till vårdgivaren. Under projektets tid har ett samarbete med DAGA-kliniken på Östra sjukhuset upprättats, genom bl.a. diskussioner om frågeformulärets utformning. Under våren 2007 har även två förstudier genomförts på kliniken, den första med inriktning mot patientdelen av systemet, och den andra mot vårdgivarsidan. Studien visar att patientdelen är lätthanterad ur patientsynpunkt samt att intresse för systemet finns. Även på vårdgivarsidan är resultaten positiva när det gäller design, funktioner och intresse, men utrymme för förbättringar finns. Fortsatta studier i form av ett längre försök i hemmet hos patienter är planerat under sommaren och hösten 2007. Under sommaren kommer även patientdelen att vidareutvecklas med ny programvara. Ett framtida projekt innefattar att utveckla en metod för att utnyttja EBI (Elektrisk Bio-Impedans). Med relativt enkla och robusta mätningar förväntas mycket användbar och relevant information om sjukdomstillståndet kunna erhållas med denna metod, men detta kräver att ny sensorteknik utvecklas för hemmiljön.
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| 4. |
- Löfhede, Johan, 1978, et al.
(författare)
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Automatic classification of background EEG activity in healthy and sick neonates
- 2010
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Ingår i: Journal of Neural Engineering. - : IOP Publishing. - 1741-2560 .- 1741-2552. ; 7:1
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Tidskriftsartikel (refereegranskat)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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| 5. |
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| 6. |
- Marquez, Juan Carlos, 1976-, et al.
(författare)
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Textile electrode straps for wrist-to-ankle bioimpedance measurements for Body Composition Analysis : Initial validation & experimental results
- 2010
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Ingår i: 2010 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC). - : IEEE Engineering in Medicine and Biology Society. - 9781424441235 ; 2010, s. 6385-8
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Konferensbidrag (refereegranskat)abstract
- Electrical Bioimpedance (EBI) is one of the non-invasive monitoring technologies that could benefit from the emerging textile based measurement systems. If reliable and reproducible EBI measurements could be done with textile electrodes, that would facilitate the utilization of EBI-based personalized healthcare monitoring applications. In this work the performance of a custom-made dry-textile electrode prototype is tested. Four-electrodes ankle-to-wrist EBI measurements have been taken on healthy subjects with the Impedimed spectrometer SFB7 in the frequency range 5 kHz to 1 MHz. The EBI spectroscopy measurements taken with dry electrodes were analyzed via the Cole and Body Composition Analysis (BCA) parameters, which were compared with EBI measurements obtained with standard electrolytic electrodes. The analysis of the obtained results indicate that even when dry textile electrodes may be used for EBI spectroscopy measurements, the measurements present remarkable differences that influence in the Cole parameter estimation process and in the final production of the BCA parameters. These initial results indicate that more research work must be done to in order to obtain a textile-based electrode that ensures reliable and reproducible EBI spectroscopy measurements.
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| 7. |
- Pau, Ivan, et al.
(författare)
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Home e-health system integration in the Smart Home through a common media server.
- 2009
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Ingår i: EMBC: 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20. - 9781424432967 ; 2009, s. 6171-4
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Konferensbidrag (refereegranskat)abstract
- Home e-health systems and services are revealed as one of the most important challenges to promote Quality of Life related to Health in the Information Society. Leading companies have worked on e-health systems although the majority of them are addressed to hospital or primary care settings. The solution detailed in this paper offers a personal health system to be integrated with Smart Home services platform to support home based e-care. Thus, the home e-health system and architecture detailed in this research work is ready to supply a seamless personal care solution both from the biomedical data analysis, service provision, security guarantee and information management s point of view. The solution is ready to be integrated within the Accessible Digital Home, a living lab managed by Universidad Politécnica de Madrid for R&D activities.
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| 8. |
- Seoane, Fernando, 1976-, et al.
(författare)
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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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Ingår i: Proceedings of the 3rd IEEE-EMBS International Conference on Neural Engineering. - : IEEE. - 1424407923 ; , s. 256 - 260
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Konferensbidrag (refereegranskat)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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