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Nerve conduction and electromyography studies

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Abstract

Nerve conduction studies (NCS) and electromyography (EMG), often shortened to ‘EMGs’, are a useful adjunct to clinical examination of the peripheral nervous system and striated skeletal muscle. NCS provide an efficient and rapid method of quantifying nerve conduction velocity (CV) and the amplitude of both sensory nerve action potentials (SNAPs) and compound motor action potentials (cMAPs). The CV reflects speed of propagation of action potentials, by saltatory conduction, along large myelinated axons in a peripheral nerve. The amplitude of SNAPs is in part determined by the number of axons in a sensory nerve, whilst amplitude of cMAPs reflects integrated function of the motor axons, neuromuscular junction and striated muscle. Repetitive nerve stimulation (RNS) can identify defects of neuromuscular junction (NMJ) transmission, pre- or post-synaptic. Needle EMG examination can detect myopathic changes in muscle and signs of denervation. Combinations of these procedures can establish if motor and/or sensory nerve cell bodies or peripheral nerves are damaged (e.g. motor neuronopathy, sensory ganglionopathy or neuropathy), and also indicate if the primary target is the axon or the myelin sheath (i.e. axonal or demyelinating neuropathies). The distribution of nerve damage can be determined as either generalised, multifocal (mononeuropathy multiplex) or focal. The latter often due to compression at the common entrapment sites (such as the carpal tunnel, Guyon’s canal, cubital tunnel, radial groove, fibular head and tarsal tunnel, to name but a few of the reported hundred or so ‘entrapment neuropathies’).

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References

  1. Al-Shekhlee A, Shapiro BE, Preston DC (2003) Iatrogenic complications and risks of nerve conduction studies and needle electromyography. Muscle Nerve 27:517–526

    Article  PubMed  Google Scholar 

  2. Bromberg MB, Albers JW (1993) Patterns of sensory nerve conduction abnormalities in demyelinating and axonal peripheral nerve disorders. Muscle Nerve 16:262–266

    Article  PubMed  CAS  Google Scholar 

  3. Campbell WW (2008) Evaluation and management of peripheral nerve injury. Clin Neurophysiol 119:1951–1965

    Article  PubMed  Google Scholar 

  4. Camdessanché JP, Jousserand G, Ferraud K, Vial C, Petiot P, Honnorat J, Antoine JC (2009) The pattern and diagnostic criteria of sensory neuronopathy: a case-control study. Brain 132(7):1723–1733

    Article  PubMed  Google Scholar 

  5. Dengler R (2012) El Escorial or Awaji criteria in ALS diagnosis, what should we take? Clin Neurophysiol 123:217–218

    Article  PubMed  Google Scholar 

  6. Falck B, Stalberg E (1995) Motor nerve conduction studies: measurement principles and interpretation of findings. J Clin Neurophysiol 12(3):254–279

    Article  PubMed  CAS  Google Scholar 

  7. Fisher MA (1998) The contemporary role of F-wave studies: clinical utility. Muscle Nerve 21:1098–1101

    Article  PubMed  CAS  Google Scholar 

  8. Kimura J (1989) Electrodiagnosis in diseases of nerve and muscle: principles and practice. FA Davis Company, Philadelphia

    Google Scholar 

  9. Le Quintrec JS, Le Quintrec JL (1991) Drug induced myopathies. Baillieres Clin Rheumatol 5(1):21–38

    Article  PubMed  Google Scholar 

  10. Lewis RA, Sumner AJ (1982) The electrodiagnostic distinctions between chronic familial and acquired demyelinative neuropathies. Neurology 32(6):592–596

    Article  PubMed  CAS  Google Scholar 

  11. Lewis RA, Sumner AJ, Shy ME (2000) Electrophysiological features of inherited demyelinating neuropathies: a reappraisal in the era of molecular diagnosis. Muscle Nerve 23:1472–1487

    Article  PubMed  CAS  Google Scholar 

  12. Rutkove SB (2001) Effects of temperature on neuromuscular electrophysiology. Muscle Nerve 24:867–882

    Article  PubMed  CAS  Google Scholar 

  13. Stålberg E, Falck B (1997) The role of electromyography in neurology. Electroenceph Clin Neurophysiol 103:579–598

    Article  PubMed  Google Scholar 

Download references

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Correspondence to N. M. Kane.

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Kane, N.M., Oware, A. Nerve conduction and electromyography studies. J Neurol 259, 1502–1508 (2012). https://doi.org/10.1007/s00415-012-6497-3

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  • DOI: https://doi.org/10.1007/s00415-012-6497-3

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