Z.M. Yuldashev - Dr. Sc. (Eng.), Professor, Head of the Department of Biotechnical Systems, Saint-Petersburg Electrotechnical University «LETI» E-mail: yuld@mail.ru M.N. Solovev - Post-graduate Student, Department of Biotechnical Systems, Saint-Petersburg Electrotechnical University «LETI»; Engineer, Firm «Diamant» Ltd (St.-Petersburg) E-mail: zenimike@gmail.com

Bioimpedance analysis (BIA) is widely used in preventive and sports medicine, cosmetology and nutrition, diagnosis of metabolic dis-orders. However this method provides non-satisfactory results in cases of patients with non-average structure of body composition. Known integral dual-frequency BIA has been chosen as referent method for a group of patients with average body stricture. It uses tetrapolar electrode scheme and the current on frequencies of 30 and 115 kHz. Also is used segmental model with measuring of impedances of torso, both hands and legs. Special attention is focused on the preliminary stage of patient observation. Ten-minute interval of fluid redistribution process is proposed to be used for first evaluations of BIA parameters which could be used for expanding incoming data of proposed BIA algorithm. Particularly the type of body composition is determined by algorithm and verified by researcher. On the main stage of observation impedances of five segments and whole body are measured on two frequencies. If poor contact of one limb electrode is detected doctor is offered to continue calculations in "mirror mode" (impedance of limb with bad connection is replaced by impedance of mirrored by sagittal axis). Calculating algorithm of proposed method has loop structure. On each iteration calculations are completed implementing to each segment of five-segmental body model and to whole body. Estimated coefficients of segmental impedances and additional anthropometric measurements are used in evaluation of body composition parameters. Integral BIA iteration uses referent method to estimate whole body composition parameters. After the finish of last iteration three data samples (all impedances and anthropometric data; segmental-based BIA parameters; referent method-s results) are being compared and used physical model coefficients are being checked for validity. By the result of this validity check additional anth-ropometrical data could be inquired as a result of the factor analysis or coefficients could be corrected by statistical server-based group classification in n-dimension space of parameters. This approach allows to correct coefficients of human body model in dependence of its real structure and to reduce methodical error. Also the procedure of measurement could be optimized by the use of statistical data to skip the part of fluids redistribution process and by the new flexible scheme of electrodes placement.

 

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