Repetitive Nerve Stimulation (RNS) is a specialized electrodiagnostic test used to assess the function of the neuromuscular junction—the point where nerves communicate with muscles. It is most commonly used to diagnose disorders like Myasthenia Gravis (MG) and other conditions that cause fatigable muscle weakness. During the procedure, small electrical pulses are delivered repeatedly to a motor nerve at a slow or rapid frequency. Surface electrodes placed on the skin record the muscle’s electrical response to each stimulus. In healthy individuals, muscle responses remain fairly consistent. However, in neuromuscular junction disorders, the muscle response gradually decreases, showing a characteristic “decrement pattern.” This helps doctors identify abnormalities in nerve-to-muscle signal transmission. The test is safe, non-invasive, and provides crucial information that cannot be obtained through routine neurological examinations. RNS also assists in monitoring disease progression and evaluating treatment effectiveness for conditions involving fatigable weakness.