New electrode system for rapid whole-body and segmental bioimpedance assessment

Skeletal muscle is a clinically important body composition component which at present is difficult to quantify in vivo. Previous studies suggest that measured appendicular resistance at 50 kHz can be used to predict extremity skeletal muscle mass, although accurate technician placement of multiple gel electrodes is required. In the present study we developed a new bioimpedance analysis (BIA) electrode stand designed for rapid whole-body and segmental resistance and reactance measurements. The new system incorporates stainless steel hand and foot contact electrodes in place of gel electrodes and employs a previously reported lead placement algorithm for deriving extremity resistances without the need for placing conventional proximal limb gel electrodes. This report describes the new electrode system's design and examines the relationships between contact and gel electrode-measured resistance and between appendicular resistance measured with the recently reported lead placement algorithm and conventionally placed segmental electrodes. Results in healthy adults demonstrate high correlations between contact and gel electrodes (e.g., hand-to-hand, N = 12, r = 0.994, P < 0.001) and between segmental resistance measured by the recently reported approach and conventionally-measured segmental resistance (e.g., right arm, N = 13; r = 0.997, P < 0.001). These results strongly support the validity of the new electrode system's resistance measurements and suggests the feasibility of developing a BIA system for rapidly measuring extremity skeletal muscle mass.