Interferential current uses two high-frequency alternating waveforms that cross to produce what in the tissue?

• A. A low-frequency beat
• B. A high-frequency current
• C. Direct current
• D. No sensation change

Answer: (A)

Interferential current works by two high-frequency waves crossing in the tissue, creating an interference pattern. When the two frequencies differ by a small amount, their superposition produces a waveform whose amplitude modulates at that difference—the beat frequency. This low-frequency envelope is what stimulates nerves and muscles, while the high-frequency carriers help the current reach deeper tissues with less skin impedance. So the tissue experiences a low-frequency beat, not a steady high-frequency current or direct current, and you’ll typically feel a sensation that changes with the beat.