A geometrical method for modeling bioelectrical impedance measurements and remove the hook effect deviations

Objective: to describe a simple and straightforward method to calculate the circle parameters that can be used to fit Electrical Bioimpedance Spectroscopy (EBIS) raw data to the complex plane and remove the hook effect, a deviation of that model especially seen at higher frequencies and considered as an artifact due to instrumental limitations. Approach: under the assumption that raw EBIS data in the middle frequencies best represent the beta dispersion, the authors of this article propose a geometrical procedure to calculate parameters for this dispersion and remove the hook effect. For this purpose, data obtained with two different devices were used with apparently very good results. Main results: the results of this study suggest that circle parameters for the beta dispersion can be obtained, but, also, that the residuals of the hook effect correction seem to adjust to a circle and, therefore, they could also be parameterized using the same approach. Significance: the method proposed in this article is very easy to perform and could help end EBIS users not familiar with mathematical models and fitting processes, to better understand and interpret their data.