Bioelectrical Impedance Methods for Noninvasive Health Monitoring: A Review.
17 Jun 2014-Vol. 2014, pp 381251-381251
TL;DR: The working principles, applications, merits, and demerits of these methods has been discussed in detail along with their other technical issues followed by present status and future trends.
Abstract: Under the alternating electrical excitation, biological tissues produce a complex electrical impedance which depends on tissue composition, structures, health status, and applied signal frequency, and hence the bioelectrical impedance methods can be utilized for noninvasive tissue characterization. As the impedance responses of these tissue parameters vary with frequencies of the applied signal, the impedance analysis conducted over a wide frequency band provides more information about the tissue interiors which help us to better understand the biological tissues anatomy, physiology, and pathology. Over past few decades, a number of impedance based noninvasive tissue characterization techniques such as bioelectrical impedance analysis (BIA), electrical impedance spectroscopy (EIS), electrical impedance plethysmography (IPG), impedance cardiography (ICG), and electrical impedance tomography (EIT) have been proposed and a lot of research works have been conducted on these methods for noninvasive tissue characterization and disease diagnosis. In this paper BIA, EIS, IPG, ICG, and EIT techniques and their applications in different fields have been reviewed and technical perspective of these impedance methods has been presented. The working principles, applications, merits, and demerits of these methods has been discussed in detail along with their other technical issues followed by present status and future trends.
Citations
More filters
01 Jan 1997
TL;DR: This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems and discusses the main points in the application to electromagnetic design, including formulation and implementation.
Abstract: This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.
1,820 citations
TL;DR: A deeper understanding of the fundamental challenges faced for wearable sensors and of the state-of-the-art for wearable sensor technology, the roadmap becomes clearer for creating the next generation of innovations and breakthroughs.
Abstract: Wearable sensors have recently seen a large increase in both research and commercialization. However, success in wearable sensors has been a mix of both progress and setbacks. Most of commercial progress has been in smart adaptation of existing mechanical, electrical and optical methods of measuring the body. This adaptation has involved innovations in how to miniaturize sensing technologies, how to make them conformal and flexible, and in the development of companion software that increases the value of the measured data. However, chemical sensing modalities have experienced greater challenges in commercial adoption, especially for non-invasive chemical sensors. There have also been significant challenges in making significant fundamental improvements to existing mechanical, electrical, and optical sensing modalities, especially in improving their specificity of detection. Many of these challenges can be understood by appreciating the body's surface (skin) as more of an information barrier than as an information source. With a deeper understanding of the fundamental challenges faced for wearable sensors and of the state-of-the-art for wearable sensor technology, the roadmap becomes clearer for creating the next generation of innovations and breakthroughs.
680 citations
TL;DR: In this article, an updated review of EIS main implementations and applications is presented, as well as a broad range of applications as a quick and easily automated technique to characterize solid, liquid, semiliquid, organic as well and inorganic materials.
Abstract: . Electrical impedance spectroscopy (EIS), in which a sinusoidal test voltage or current is applied to the sample under test to measure its impedance over a suitable frequency range, is a powerful technique to investigate the electrical properties of a large variety of materials. In practice, the measured impedance spectra, usually fitted with an equivalent electrical model, represent an electrical fingerprint of the sample providing an insight into its properties and behavior. EIS is used in a broad range of applications as a quick and easily automated technique to characterize solid, liquid, semiliquid, organic as well as inorganic materials. This paper presents an updated review of EIS main implementations and applications.
234 citations
Cites background from "Bioelectrical Impedance Methods for..."
...Fat tissues are characterized by low electrical conductivity (i.e., high impedance values) while lean tissues present high electrical conductivity (i.e., low impedance values) due to the high content of electrolytes (Kanti Bera, 2014)....
[...]
TL;DR: The basis and fundamentals of bioimpedance measurements are described covering issues ranging from the hardware diagrams to the configurations and designs of the electrodes and from the mathematical models that describe the frequency behavior of the bioimpingance to the sources of noise and artifacts.
Abstract: This work develops a thorough review of bioimpedance systems for healthcare applications. The basis and fundamentals of bioimpedance measurements are described covering issues ranging from the hardware diagrams to the configurations and designs of the electrodes and from the mathematical models that describe the frequency behavior of the bioimpedance to the sources of noise and artifacts. Bioimpedance applications such as body composition assessment, impedance cardiography (ICG), transthoracic impedance pneumography, electrical impedance tomography (EIT), and skin conductance are described and analyzed. A breakdown of recent advances and future challenges of bioimpedance is also performed, addressing topics such as transducers for biosensors and Lab-on-Chip technology, measurements in implantable systems, characterization of new parameters and substances, and novel bioimpedance applications.
87 citations
References
More filters
TL;DR: Electrical impedance tomography is a noninvasive, radiation-free monitoring tool that allows real-time imaging of ventilation and is gaining acceptance as a valuable monitoring tool for the care of critical patients.
Abstract: Electrical impedance tomography (EIT) is a non-invasive, radiation-free monitoring tool that allows real-time imaging of ventilation [1, 2, 3]. EIT was first used to monitor respiratory function in 1983 and remains the only bedside method that allows repeated, non-invasive measurements of regional changes in lung volumes [4, 5]. For this reason, EIT has been used as a monitoring tool in a variety of applications in critical care medicine, including monitoring of ventilation distribution [3, 6], assessment of lung overdistension [7] and collapse [8, 9], and detection of pneumothorax [10, 11], among others. In this chapter, we will provide a brief overview of the fundamentals of the EIT technique and review the use of EIT in critical care patients in the light of recent literature.
161 citations
TL;DR: The present study assessed the relative contribution of each body segment to whole body fat-free mass (FFM) and impedance and explored the use of segmental bioelectrical impedance analysis to estimate segmental tissue composition and provides specific segmental body composition equations for use in normal and overweight women.
Abstract: Bracco, David, Daniel Thiebaud, Rene L. Chiolero, Michel Landry, Peter Burckhardt, and Yves Schutz.Segmental body composition assessed by bioelectrical impedance analysis and DEXA in humans. J. App...
154 citations
TL;DR: BIA is a central tool in the clinical examination of patients addressing hydration, functional body mass, energy stores and prognosis, and may also serve as a monitor of disease load; a low-phase angle is associated with poor prognosis.
Abstract: It is 50 years since Thomasett demonstrated the application of the measurement of the impedance of the human body to the estimation of total body water...
151 citations
01 Jan 2004
TL;DR: In this article, it was shown that the size and time-relationships of the voltage and current signals depend on the frequency of the alternating current and voltage signals, and that the voltage signal size and current signal size depend on both the frequency and the amplitude of the current signal.
Abstract: This seemingly basic equation actually hides some sophisticated assumptions and concepts. First, it applies only to the time varying, alternating, or ac, components of the current and voltage. Secondly, it is not sufficient to just tell how big the voltage and current signals are, we must also say how they are related in time, since they are both timevarying, ac quantities. Finally, the sizeand time-relationships nearly always depend on the frequency of the alternating current and voltage.
141 citations
TL;DR: In this article, the authors used electrical impedance tomography (EIT) to demonstrate the multifunctionality of carbon nanocomposite thin films under various types of environmental stimuli.
Abstract: This paper describes the application of electrical impedance tomography (EIT) to demonstrate the multifunctionality of carbon nanocomposite thin films under various types of environmental stimuli. Carbon nanotube (CNT) thin films are fabricated by a layer-by-layer (LbL) technique and mounted with electrodes along their boundaries. The response of the thin films to various stimuli is investigated by relying on electric current excitation and corresponding boundary potential measurements. The spatial conductivity variations are reconstructed based on a mathematical model for the EIT technique. Here, the ability of the EIT method to provide two-dimensional mapping of the conductivity of CNT thin films is validated by (1) electrically imaging intentional structural defects in the thin films and (2) mapping the film's response to various pH environments. The ability to spatially image the conductivity of CNT thin films holds many promises for developing multifunctional CNT-based sensing skins.
140 citations