Robustness study of the different immittance spectra and frequency ranges in bioimpedance spectroscopy analysis for assessment of total body composition.
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 10-500 kHz 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 [10-500 kHz] and 1.04 ± 2.94 l for G [5-1000 kHz]. Regarding intracellular fluid, the correlation between dilution and the device was 0.91, same as for G [10-500 kHz] and 0.92 for G [5-1000 kHz]. Limits of agreement were 0.12 ± 4.46 l for the device, 0.09 ± 4.45 for G [10-500 kHz] and 0.04 ± 4.58 for G [5-1000 kHz]. 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.
Department of Medical Sensors, Signals and Systems, KTH-Royal Institute of Technology, Alfred Nobels Allé 10, SE-14152 Huddinge, Stockholm, Sweden. Department of Signal Theory and Communications, University of Alcala, E-28871, Madrid, Spain. School of Engineering, University of Borås, SE-50190 Borås, Sweden.
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Buendia
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Seoane
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Bosaeus
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Gil-Pita
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Johannsson
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Ellegård
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Lindecrantz
D000465:Algorithms; D001823:Body Composition / Q000187:drug effects; D001826:Body Fluids / Q000187:drug effects / Q000502:physiology; D003198:Computer Simulation; D016208:Databases, Factual; D058266:Dielectric Spectroscopy / Q000379:methods*; D025802:Electric Capacitance; D017097:Electric Impedance; D045604:Extracellular Fluid / Q000502:physiology; D005240:Feasibility Studies; D005260:Female; D013006:Growth Hormone / Q000627:therapeutic use; D020249:Hormone Replacement Therapy; D006801:Humans; D007424:Intracellular Fluid / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012044:Regression Analysis
D013006:Growth Hormone