Teaching Video NeuroImages: Electromyographic variation in stiff-person syndrome.

A 58-year-old man diagnosed with stiff-person syndrome presented with increased axial muscle tone (video 1, links.lww.com/WNL/A42). A successional electromyographic video in the right rectus abdominis demonstrated a large quantity of continuous motor unit potentials at rest. One minute after administration of diazepam, motor unit potentials were extraordinarily attenuated. However, 10 minutes after diazepam administration, the motor unit potentials were gradually restored (video 2, links.lww.com/WNL/A43). This case gives us a better understanding of the clinical manifestation of stiff-person syndrome and shows more intuitive electrophysiologic hallmarks of this rare disease.