Electrodiagnostic testing, more commonly known as the EMG test, to many is a “black box.” It is a commonly ordered test that can provide very definitive information that is often not well understood. A large amount of information is usually provided, yet most clinicians rely primarily on the concluding statements, which may or may not be well substantiated. Added insight into this test demands understanding some basic facts about the “EMG” test and dispelling some of the myths.
The timing for ordering an EMG study
One of the most common myths about EMG tests is that one must wait 2–3 weeks following a nerve injury before reliable information can be obtained. It is true that the degree of muscle denervation that occurs after nerve injury can not be determined until Wallerian degeneration is complete and this can take as short as 1 week or as long as 4 weeks . This is a length-dependent process so that the longer the length of the injured axon, the longer Wallerian degeneration will...
KeywordsMotor Unit Nerve Conduction Study Axonal Regeneration Neurological Recovery Motor Unit Recruitment
- 1.Dumitru, D, Zwarts, MJ 2005Needle electromyographyDumitru, DAmato, AAZwarts MJ, MJ eds. Electrodiagnostic medicineHanley and BelfusPhiladelphia257292Google Scholar
- 2.Herbison, GJ 1984Neuropathic Needle Examination. AAEM Course A: Fundamentals of EMGAmerican Association of Electrodiagnostic MedicineRochester, MN2125Google Scholar
- 9.Buchthal, F 1982Fibrillations: clinical electrophysiologyCulp, WJOchoa, J eds. Abnormal nerves and muscle generatorsOxford University PressNew York632662Google Scholar
- 10.Campbell WW (2002) Electrophysiological approaches to the diagnosis and assessment of ulnar neuropathy. 2002 AAEM Plenary Session Toronto, Ontario, American Association of Electrodiagnostic Medicine, pp. 13–22Google Scholar
- 11.Dumitru, D, Zwarts, MJ 2002Focal peripheral neuropathiesDumitru, DAmato, AAZwarts, MJ eds. Electrodiagnostic medicineHanley and BelfusPhiladelphia10431126Google Scholar