Compound muscle action potential postexercise facilitation

Exercise testing in LEMS, with the median nerve stimulated supramaximally at the wrist and the abductor pollicis brevis muscle recorded. Top: Baseline. Bottom: Immediately after 10 seconds of maximal voluntary exercise. Note marked increase in compound muscle action potential amplitude (post-exercise facilitation). Pre-exercise and post-exercise testing, looking for an increment, always is better tolerated by patients than is 50 Hz repetitive nerve stimulation.