Electrophysiological study of neuromuscular system involvement in mitochondrial cytopathy

P. Girlanda, A. Toscano, C. Nicolosi, S. Sinicropi, G. Picciolo, V. Macaione, A. Quartarone, C. Messina

Research output: Contribution to journalArticlepeer-review


Objectives: To define the neuromuscular involvement in 'mitochondrial' patients with clinical evidence of a neuromuscular disorder, and to evaluate if the proposed electrophysiological protocol was suitable to reveal a subclinical neuropathy or myopathy in 'mitochondrial' patients with no clinical sign of a neuromuscular disturbance. Methods: Quantitative concentric needle electromyography (CNEMG), single fiber electromyography (SFEMG) and nerve conduction studies (NCS) were performed in 33 patients with mitochondrial cytopathies. Lastly, we studied 9 clinically unaffected relatives. Results: NCS were abnormal in 18% of patients, with CNEMG and SFEMG in 58% of cases, but there was not a complete overlapping of the positivity of the different techniques. No asymptomatic relatives showed abnormalities of the electrophysiological studies. Conclusions: Electrophysiological findings did not correlate with any specific biochemical or genetic defect, but were consistent with clinical diagnosis in almost all of the patients with clinical signs of myopathy and/or neuropathy. Increase of both SFEMG jitter and fiber density was significantly tied of a neuropathic process. CNEMG and SFEMG were altered in about 30% of subjects without clinical signs of myopathy or neuropathy and were therefore able to reveal a subclinical involvement of neuromuscular system in some patients who had external ophthalmoplegia or retinitis only.

Original languageEnglish
Pages (from-to)1284-1289
Number of pages6
JournalClinical Neurophysiology
Issue number7
Publication statusPublished - Jul 1 1999


  • Concentric needle electromyography
  • Mitochondrial cytopathies
  • Nerve conduction studies
  • Single fiber electromyography

ASJC Scopus subject areas

  • Clinical Neurology
  • Physiology (medical)
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Sensory Systems


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