Development of a Segmental Bioelectrical Impedance Spectroscopy Device for Body Composition Measurement

Whole-body bioelectrical impedance analysis for measuring body composition is well explored but may not be sensitive enough to changes in the trunk compared to changes in the limbs. Measuring individual body segments can address this issue. A segmental bioelectrical impedance spectroscopy device, the SBISD, was designed for body composition measurement, and a prototype was implemented. Compensation was performed to adjust the measured values to correct for phase difference at high frequencies and to counteract the hook effect when measuring the human body. The SBISD was used to measure an RRC test cell to confirm it measured appropriately, and measurements were within 1% of the expected value. Then, the SBISD was used to measure three subjects and compared against three existing analyzers. SEE was used as a measure of how well the measured data points fit to the expected semicircular shape of the Cole-Cole plot. The arm had SEE of 1.6 Ω, 1.3 Ω, 0.6 Ω, 1.5 Ω, and 0.8 Ω for subjects 1 through 5, respectively. For the trunk segment, SEE was 0.4 Ω, 0.4 Ω, 0.2 Ω, 0.5 Ω, and 0.5 Ω. For the leg segment, SEE was 0.7 Ω, 1.6 Ω, 1.0 Ω, 1.0 Ω, and 0.9 Ω. For most segmental measurements, the SBISD was within 10% of the R0 and R∞ values determined with a Bodystat Multiscan 5000 and an Impedimed SFB7. The impedance values from the third reference device, a Seca 514, differed significantly due to its 8-electrode measuring technique, meaning impedance measurements could not be compared directly