Effect of Electrode Size, Shape, and Placement During Electrical Stimulation

Objective: The effect of electrode size, shape, and placement during electrical stimulation of the biceps, quadriceps, and tibialis anterior muscles were studied to assess what current is required during current-controlled electrical stimulation (ESI) to reach a set muscle force, as well as to evaluate patient comfort. Methods: The electrodes used were round, square, and square with a serrated edge (with similar surface areas of 25.8 cm2); electrode sizes were 3.66 cm2, 4.39 cm2, and 5.08 cm2. Electrodes were placed at distances from the motor point of 2 cm and 4 cm proximal, distal, medial, and lateral, using a 3.66-cm2 pad. Associated subject comfort was recorded on a visual analogue pain scale (VAS) and assessed by heart rate, blood flow, galvanic skin resistance, and skin temperature. Results: Significant increases were found in ESI and VAS scores for placements away from the motor point, but there were no significant differences in ESI and VAS scores among the electrode size and shapes. Specifically, there was a statistically significant increase in ESI