Conventional TENS usage is based on which gate theory?

• A. All or none
• B. Open gate
• C. Close gate
• D. No gate

Answer: (C)

Gate control theory explains how non-painful input can dampen painful signals at the spinal cord level. Conventional TENS delivers high-frequency electrical pulses that primarily stimulate large-diameter A-beta fibers. This input activates inhibitory interneurons in the dorsal horn, which suppress the transmission of pain signals carried by C and A-delta fibers to the brain. The result is a closed gate on the pain pathway, producing immediate analgesia while the stimulation is on. That’s why the best answer describes closing the gate.

If the gate were open, pain signals would pass more freely; if there were no gate, there would be no modulation of pain transmission. The “all or none” option doesn’t fit this mechanism.