Exercise testing in Lambert-Eaton myasthenic syndrome

Exercise testing in Lambert-Eaton myasthenic syndrome, 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 (postexercise facilitation). Preexercise and postexercise testing, looking for an increment, always is better tolerated by patients than is 50-Hz repetitive nerve stimulation.