The difficulty in confirming clinical diagnosis of myasthenia gravis in a seronegative patient: A possible neurophysiological approach

P. Caliandro, A. Evoli, E. Stålberg, G. Granata, P. Tonali, L. Padua

Research output: Contribution to journalArticle


In seronegative myasthenia gravis repetitive nerve stimulation and single-fibre EMG have a crucial diagnostic value but they may be negative, particularly in repetitive nerve stimulation studies. We report the case of a 43-year-old patient with generalized seronegative myasthenia gravis with negative 3 Hz repetitive nerve stimulation at Erb's point and voluntary single-fibre EMG in the orbicularis oculi. We also performed 6 and 12 Hz repetitive nerve stimulation at Erb and stimulated single-fibre EMG in the extensor digitorum communis and our findings were pathological. Our data suggest that, for individual patients with an atypical picture characterised by dissociation between a severe clinical pattern and no definite neurophysiological findings on conventional tests, repetitive nerve stimulation with a stimulation rate higher than 3 Hz and/or stimulated single-fibre EMG with an increasing stimulation rate may be helpful.

Original languageEnglish
Pages (from-to)825-827
Number of pages3
JournalNeuromuscular Disorders
Issue number12
Publication statusPublished - Dec 2009



  • Myasthenia gravis
  • Repetitive nerve stimulation
  • Single fibre

ASJC Scopus subject areas

  • Clinical Neurology
  • Pediatrics, Perinatology, and Child Health
  • Genetics(clinical)
  • Neurology

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