Title 



A new measuring and identification approach for timevarying bioimpedance using multisine electrical impedance spectroscopy
 
Author 



 
Abstract 



The bioimpedance measurement/identification of timevarying biological systems Z(omega, t) by means of electrical impedance spectroscopy (EIS) is still a challenge today. This paper presents a novel measurement and identification approach, the socalled parametricintime approach, valid for timevarying (bio) impedance systems with a (quasi) periodic character. The technique is based on multisine EIS. Contrary to the widely used nonparametricintime strategy, the (bio) impedance Z(omega, t) is assumed to be timevariant during the measurement interval. Therefore, timevarying spectral analysis tools are required. This new parametricintime measuring/identification technique has experimentally been validated through three independent sets of in situ measurements of in vivo myocardial impedance. We show that the timevarying myocardial impedance Z(omega, t) is dominantly periodically time varying (PTV), denoted as Z(PTV)(omega, t). From the temporal analysis of Z(PTV)(omega, t), we demonstrate that it is possible to decompose Z(PTV)(omega, t) into a(n) (in) finite sum of fundamental (bio) impedance spectra, the socalled harmonic impedance spectra (HIS) Z(k)(omega)s with k is an element of Z. This is similar to the wellknown Fourier series of a periodic signal, but now understood at the level of a periodic system's frequency response. The HIS Z(k)(omega) s for k is an element of Z \{0} actually summarize in the bifrequency (omega, k) domain all the temporal incycle information about the periodic changes of Z(omega, t). For the particular case k = 0 (i.e. on the omegaaxis), Z(0)(omega) reflects the mean incycle behavior of the timevarying bioimpedance. Finally, the HIS Z(k)(omega)s are directly identified from noisy current and voltage myocardium measurements at the multisine measurement frequencies ( i.e. nonparametricinfrequency).   
Language 



English
 
Source (journal) 



Physiological measurement / Institute of Physical Sciences in Medicine.  Bristol, 1980, currens  
Publication 



Bristol : IOP, 2013
 
ISSN 



09673334
 
Volume/pages 



34:3(2013), p. 339357
 
ISI 



000315441100009
 
Full text (Publisher's DOI) 


  
