In electrotherapy, the order in which a stimulus is felt from first to last is:

In electrotherapy, the order in which a stimulus is felt from first to last is:

• A. Motor, Sensory, Pain
• B. Sensory, Motor, Pain
• C. Pain, Sensory, Motor
• D. Sensory, Pain, Motor

Answer: (B)

When electrical stimulation is applied, fibers with the largest diameter and myelination are recruited first because they have the lowest threshold. That means the initial percept is a sensory sensation (tingling or buzzing) carried by A-beta fibers. As the current increases, motor fibers (A-alpha) are activated, producing a muscle contraction. Only with even higher intensities do nociceptive fibers (pain pathways, A-delta and C) reach threshold and the person feels pain or a sharp discomfort. So the familiar sequence during electrotherapy is sensory, then motor, then pain. The other sequences would require pain or motor to occur before sensory, which doesn’t match the typical recruitment thresholds of these fiber types.

When electrical stimulation is applied, fibers with the largest diameter and myelination are recruited first because they have the lowest threshold. That means the initial percept is a sensory sensation (tingling or buzzing) carried by A-beta fibers. As the current increases, motor fibers (A-alpha) are activated, producing a muscle contraction. Only with even higher intensities do nociceptive fibers (pain pathways, A-delta and C) reach threshold and the person feels pain or a sharp discomfort. So the familiar sequence during electrotherapy is sensory, then motor, then pain. The other sequences would require pain or motor to occur before sensory, which doesn’t match the typical recruitment thresholds of these fiber types.