Effects of Carrier Frequency of Interferential Current on Pressure Pain Threshold and Sensory Comfort in Humans

ObjectiveTo assess the effect of carrier frequency of interferential current (IFC) on pressure pain threshold (PPT) and sensory comfort in healthy subjects.DesignA double-blind randomized trial.SettingUniversity research laboratory.ParticipantsHealthy subjects (N=150).InterventionsApplication of the IFC for 20 minutes and measures of PPT collected in the regions of the nondominant hand and forearm.Main Outcomes MeasuresWe measured PPT and comfort at frequencies of 1kHz, 2kHz, 4kHz, 8kHz, and 10kHz.ResultsThere was a significant increase in PPT in the 1-kHz group when compared with the 8-kHz and 10-kHz groups. There was a greater discomfort in the 1-kHz and 2-kHz groups.ConclusionsIFC with a carrier frequency of 1kHz promotes a higher hypoalgesic response during and after stimulation than IFC with carrier frequencies of 8kHz and 10kHz. Carrier frequencies of 1kHz and 2kHz are perceived as more uncomfortable than carrier frequencies of 4kHz, 8kHz, and 10kHz.