Repetitive nerve stimulation (RNS) study in myasthenia gravis

Successive compound motor action potentials (CMAPs) from the abductor pollicis brevis muscle are displayed after six stimuli at 3 Hertz. A decremental response (ie, a decline in the response amplitude) is seen. It is maximal at 38 percent by the fourth response in this example. Sensitivity: 5 mV/div; Sweep speed: 5 msec/div.