Effect of interference current on forearm vascular resistance in asymptomatic humans

Physical Therapy Center of Rhinelander, WI 54501.

BACKGROUND AND PURPOSE. Several case reports suggest that transcutaneous application of interference current (IC) produces physical blockade of sympathetic vasoconstrictor fibers in peripheral nerves. To test this theory, we studied the effects of IC on forearm vascular resistance in asymptomatic humans. SUBJECTS. One man and four women, aged 21 to 44 years (mean = 33, SD = 12), served as subjects. METHODS. We measured forearm blood flow during IC applications over the left stellate ganglion. Forearm vascular resistance was calculated by dividing mean arterial pressure by forearm blood flow. RESULTS. Interference current did not alter flow (mean = 5.6 [SD = 1.0] versus 6.2 [SD = 1.1] mL/100 mL/min) or resistance (mean = 15.4 [SD = 3.1] versus 13.8 [SD = 2.4] units). When sympathetic outflow was augmented using lower-body suction, IC again failed to alter flow or resistance. CONCLUSION AND DISCUSSION. Interference current applied over the stellate ganglion does not alter forearm hemodynamics in asymptomatic individuals. These findings challenge the concept that IC can block sympathetic vasoconstrictor impulses in peripheral nerves.