A 58-year-old man with progressive stiffness Teaching NeuroImages Neurology Resident and Fellow Section © 2017American Academy of Neurology

Vignette A 58-year-old man presented with difficulty in walking due to progressive muscular rigidity in his lower limbs and trunk with muscle spasms for more than five years. The rigidity begins insidiously at the truncal muscles and spreads to the legs. Physical examination revealed neck stiffness combined with board-like rigidity of anterior abdomen. He had slow and stiff gait. It was difficult for him to get up and he could neither dress nor undress by himself due to the muscle spasms of his trunk. Electromyography in the right rectus abdominis demonstrated a large quantity of continuous motor unit potentials at rest and can be abolished rapaidly by administration of diazepam. He showed a remarkable and sustained improvement to treatment with diazepam and muscle relaxant medications, regaining independent ambulation. Jing et al © 2017American Academy of Neurology

Video Jing et al © 2017 American Academy of Neurology Video Legend This video shows he has neck stiffness combined with board-like rigidity of anterior abdomen. It is difficult for him to get up due to the muscle spasms of his trunk, his gait is stiffness, he can neither dress nor undress by himself. Jing et al © 2017 American Academy of Neurology

Video Jing et al © 2017 American Academy of Neurology Video Legend This video demonstrates a change of the electromyographic findings in the right rectus abdominis of this patient before and after the administration of diazepam for 1 minute, 3 minutes, 5 minutes and ten minutes, which is continuous motor activity can be abolished rapidly by the administration of diazepam, but it is a short duration. Jing et al © 2017 American Academy of Neurology

Electromyographic variation in stiff person syndrome Typical electromyographic findings of Stiff person syndrome is continuous motor activity abolished by the intravenous administration of diazepam or a positive response to a therapeutic trial of orally administered diazepam. This case gives us a better understanding of the clinical manifestation of this rare disease and shows us a more intuitive transformation of the electrophysiological hallmarks in the patient with stiff person syndrome after administration of diazepam. Duddy ME, Baker MR. Stiff person syndrome. Frontiers of neurology and neuroscience 2009; 26:147-165. Jing et al © 2017American Academy of Neurology