Which of the following is a recognized stimulation type used for pain control?

• A. Conventional TENS
• B. Iontophoresis
• C. Electrical Muscle Stimulation
• D. Ultrasound Therapy

Answer: (A)

Conventional TENS is a recognized electrical stimulation method specifically used for pain relief. It works by delivering a high-frequency, low-intensity current that activates large-diameter sensory fibers, which helps inhibit pain signal transmission at the spinal cord level (the gate control effect). It can also promote the release of endogenous opioids with different settings, providing immediate, temporary analgesia.

Iontophoresis uses current to push medication through the skin, not primarily to modulate pain signals via nerve stimulation. Electrical Muscle Stimulation aims to elicit muscle contractions for strength and function, not primarily for pain control. Ultrasound therapy uses mechanical energy (sound waves) rather than electrical stimulation. So, the option that best fits a recognized stimulation type used for pain control is conventional TENS.