Factors Affecting and Adjustments for Sex Differences in Current Perception Threshold With Transcutaneous Electrical Stimulation in Healthy Subjects

OBJECTIVE: Current perception threshold (CPT) measurement is a noninvasive, easy, and semi‐objective method for determining sensory function using transcutaneous electrical stimulation. Previous studies have shown that CPT is determined by physical characteristics, such as sex, age, physical sites, and presence of neuropathy. Although the CPT reported in males is clearly higher than that in females, the reason for this difference remains unclear. This study investigates the cause of sex‐based differences in CPT and suggests an adjustment method, which may suppress the sex difference in CPT. MATERIALS AND METHODS: Electrical stimulation was applied with PainVision® via five sizes of circular surface electrodes. Seventy healthy participants were examined thrice under each electrode. The relationship among body water percentage, body fat percentage, and CPT was then analyzed. RESULTS: CPT values are higher in males than that in females, with statistically significant sex differences with each electrode pairs (EL 1: p < 0.001; EL 2: p = 0.006; EL 3: p < 0.001; EL 4: p < 0.001; EL 5: p < 0.001). By adjusting for body fat percentage or body water percentage, the log‐transformation values (CPT values) no longer exhibit sex differences with any electrode pairs (body fat: p = 0.09; body water: p = 0.08). CONCLUSION: We conclude that sensitivity for perceiving electrical stimulation can be influenced by the subjects' characteristics, such as body fat or body water percentages.