This Clinical UM guideline addresses the use of electromyography and nerve conduction studies (EMG/NCS) in the outpatient setting.  Needle EMG and NCS typically comprise the electrodiagnostic evaluation of function of the motor neurons, nerve roots, peripheral nerves, neuromuscular junction and skeletal muscles.

Note: For information related to the use of automated nerve conduction testing with portable devices, such as the NC-stat^® System, see:

• MED.00092 Automated Nerve Conduction Testing.

 Medically Necessary:

Needle EMG when performed with NCS at the same time as testing are considered medically necessary for diagnosing neuropathy with sensory loss, weakness and/or muscle atrophy for any of the following indications:

• Unexplained peripheral neuropathy with pain of a neuropathic pattern, demonstrated sensory loss, or motor loss on physical examination; OR
• Neuropathy suspected to be due to trauma; OR
• When test results are expected to guide the management of conditions known to cause neuropathy, including but not limited to:
  • HIV-positive individuals with symptoms of neuropathy; or
  • Mononeuropathies, such as Bell's palsy of the facial nerve; or
  • Diabetics with persistent or progressive symptoms refractory to conventional treatments; or
  • Those on dialysis or those considering dialysis; OR
• Suspected neural impingement or entrapment where symptoms are persistent or unresponsive to initial conservative treatments, as indicated by any of the following:
  • Carpal tunnel syndrome (when clinical documentation shows impingement symptoms refractory to activity modification and at least 4 weeks of wrist splint use); or
  • Ulnar neuropathy at the elbow or wrist (when clinical documentation shows impingement symptoms refractory to activity modification and at least 4 weeks of elbow pad use); or
  • Cervical/lumbar radiculopathy (when clinical documentation shows 4-6 weeks of failed conservative therapy, including physical therapy AND where the etiology of the radicular symptoms is not explained by MRI or other diagnostic studies); or
  • Tarsal tunnel syndrome (when clinical documentation shows pain and numbness isolated to the foot); or
  • Peroneal palsy with foot drop; or
  • Suspected brachial or lumbosacral plexus impingement; or
  • Other peripheral nerve entrapment syndromes; OR
• Significant clinical suspicion for any of the following conditions:
  • Amyotrophic lateral sclerosis; or
  • Guillain-Barre syndrome; or
  • Hereditary myopathies, (e.g., muscular dystrophy); or
  • Hereditary neuropathies, (e.g., Charcot-Marie-Tooth disease); or
  • Inflammatory myopathies, (e.g., polymyositis, chronic inflammatory demyelinating polyneuropathy [CIDP]); or
  • Inflammatory/idiopathic brachial or lumbosacral plexopathy; or
  • Neuromuscular junction disease, (e.g., myasthenia gravis, Eaton Lambert syndrome); or
  • Post-polio syndrome.

Note:

In cases of carpal tunnel syndrome or ulnar neuropathy, the requirement for a period of conservative treatment may be waived if the physical exam demonstrates significant atrophy and/or weakness or sensory loss.

NCS performed without needle EMG at the same time are considered medically necessary in the following clinical situations:

• Evaluation of suspected carpal or tarsal tunnel syndrome;
• Evaluation of suspected acute nerve injury (that is within 3 weeks of occurrence);
• In individuals on anticoagulant therapy (not merely anti-platelet treatments);
• In individuals with significant lymphedema;
• Evaluation of suspected peroneal palsy;
• Evaluation of thoracic outlet syndrome;
• For facial nerve monitoring in Bells palsy. 

Needle EMG performed without NCS at the same time is considered medically necessary for the evaluation of suspected radiculopathy. 

Not Medically Necessary: 

Needle EMG performed with NCS are considered not medically necessary when the criteria listed above are not met, including as a screening tool for the general population, in the absence of related symptoms.

NCS performed without needle EMG at the same time is considered not medically necessary except the limited clinical situations listed above.

Needle EMG performed without NCS at the same time is considered not medically necessary when the criteria listed above are not met.

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

In EMG, electrical potentials are detected by a needle electrode inserted directly into a skeletal muscle. This test is useful in the outpatient evaluation of the motor neuron, nerve root, peripheral nerve, neuromuscular junction and the muscle itself. It is helpful in distinguishing between inflammatory and chronic, metabolic or inherited muscle diseases, and in differentiating between acute, recovering, and chronic denervation. While EMG may not necessarily provide a clinical diagnosis, patterns of EMG abnormalities may suggest specific pathologic entities.

NCS performed in the outpatient setting provide information regarding the presence, severity and location of a peripheral neuropathy, mononeuropathy, or disorders affecting the neuromuscular junction. Additional information suggested by NCS includes the functional modality most involved (sensory or motor) and the predominant pattern of pathology, (e.g., axonal, demyelinating, or both).

EMG/NCS tests require needle insertion and then repositioning at multiple sites and at anatomically critical areas, in order to assist in clinical diagnosis, prognosis, and clinical management decisions. In NCS, surface electrodes are usually used for both stimulation and recording of the electrical responses.  However, needle electrodes are sometimes needed to evaluate a deep nerve, such as the sciatic or the femoral nerve.

EMG/NCS is most effective when preliminary investigation (including history and neurologic examination) is suggestive of a significant probability of pathology. EMG/NCS should be performed and interpreted by individuals with appropriate training and expertise and should be evaluated in the context of the individual clinical scenario.

It is the position of the American Association of Neuromuscular and Electrodiagnostic Medicine, in its Recommended Policy for Electrodiagnostic Medicine (AANEM, 2004), that the selection of the number and type of specific EMG/NCS tests to be performed on an individual is best determined by the testing physician, based on multiple factors, including: the referral diagnosis, presenting symptoms, medical history, findings on prior clinical examination/diagnostic testing, and suspected etiology. The AANEM states further that, except in unique situations, needle EMG and NCS should be performed together in a study design determined by a trained physician, in order that healthcare decisions are based on complete diagnostic information.  Some excerpted comments follow:

Nerve conduction studies performed independent of needle EMG may only provide a portion of the information needed to diagnose muscle, nerve root, and most nerve disorders. When the NCS is used on its own without integrating needle EMG findings, or when an individual relies solely on a review of NCS data, the results can be misleading and important diagnoses may be missed.  Moreover, individuals who interpret NCS data without patient interaction or who rely on studies that have delayed interpretation, who have interpretation made off-site, and who interpret results without complementary information obtained from EMG studies are not meeting the standards outlined in the AANEM policy recommendations (AANEM, 2004).

These recommendations from the AANEM were reiterated in 2006 without any changes to the guidance statements.  Please see the Table of Maximum Number of Studies per diagnostic category recommended by the AANEM, as reasonably necessary for a physician to arrive at a diagnosis in 90% of individuals with that final diagnosis.

Peer Reviewed Publications:

1. Gooch CL, Weimer LH. The electrodiagnosis of neuropathy: basic principles and common pitfalls. Neurol Clin. 2007; 25(1):1-28.
2. Hilburn JW. General principles and use of electrodiagnostic studies in carpal and cubital tunnel syndrome. With special attention to pitfalls and interpretation. Hand Clin. 1996; 12(2):205-221.
3. Katz, J, Simon B. Carpal Tunnel Syndrome. N Engl J Med. 2002; 346:1807-1812.
4. Kaufman MA. Differential diagnosis and pitfalls in electrodiagnostic studies and special tests for diagnosing compressive neuropathies. Orthop Clin North Am. 1996; 27(2):245-252.
5. Marciniak C, Armon C, Wilson J, Miller R. Practice parameter: Utility of electrodiagnostic techniques in evaluating patients with suspected peroneal neuropathy. An evidence-based review. Muscle Nerve. 2005; 31(4):520-527.
6. Megerian JT, Kong X, Gozani SN. Utility of nerve conduction studies for carpal tunnel syndrome by family medicine, primary care, and internal medicine physicians. J Am Board Fam Med. 2007; 20(1):60-64.
7. Mendell JR, Sahenk Z. Painful sensory neuropathy. Southern Reg Med CTR. September 19th 2003. N Engl J Med. 2003; 348:1243-1255.
8. Tankisi H, Pugdahl K, Euglsang-Frederiksen A, et al. Pathophysiology inferred from electrodiagnostic nerve tests and classification of polyneuropathies. Suggested guidelines. Clin Neurophysiol. 2005; 116(7):1571-1580.

Government Agency, Medical Society, and Other Authoritative Publications:Index

1. Agency for Healthcare Research and Quality (AHRQ). Chapell R, Bruening W, Mitchell MD, et al. Diagnosis and treatment of worker-related musculoskeletal disorders of the upper extremity. Health Technology Assessments. 2002. No. 62.
2. American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM, formerly AAEN). Recommended Policy for Electrodiagnostic Medicine. Rochester, MN. September 1997 and updated 2004.  Endorsed by the American Academy of Neurology, the American Academy of Physical Medicine and Rehabilitation, and the American Association of Neuromuscular and Electrodiagnostic Medicine. Available at:. http://www.aanem.org/getmedia/b0af02d9-943c-4f78-aa91-91da3f582b49/Recommended_Policy_EDX_Medicine_07152010.pdf.aspx.  Accessed on September 29, 2011.
3. American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM).  Proper performance and interpretation of electrodiagnostic studies.  Position statement.  Approved September 2005.  Muscle Nerve. 2006; 33:436-439.  Available at:  http://www.aanem.org/getmedia/9b4fa3d5-c127-4c3d-9296-b650e443b2cc/ProperPerformance.pdf.aspx. Accessed on September 29, 2011.
4. American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM). Technologists Conducting Nerve Conduction Studies and Somatosensory Evoked Potential Studies Independently to be Reviewed by a Physician at a Later Time. May 1999. Updated and approved June 2009. Available at: http://www.aanem.org/getmedia/0ecf23a8-1e4e-41a0-b244-b818e3af5333/TechsNCSSEP062509.pdf.aspx. Accessed on September 30, 2011.
5. American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM). Reporting the results of needle EMG and nerve conduction studies: An educational report. ^©2005 American Association of Neuromuscular & Electrodiagnostic Medicine. Available at: http://www.aanem.org/getmedia/670b50d3-bb67-4d22-85f5-517b7221ca25/RptResultsEMGNCS.pdf.aspx. Accessed on September 30, 2011.
6. American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM).  Model Policy for Needle Electromyography and Nerve Conduction Studies.  2010.  Available at:  http://www.aanem.org/getmedia/29c2a525-d8b5-4a59-8ac4-04bafafab972/Model_Policy_NCS_EMG_062810.pdf.aspx.  Accessed on September 29, 2011.
7. American Medical Association (AMA). Appendix J -- Electrodiagnostic medicine listing of sensory, motor, and mixed nerves. Current Procedural Terminology (CPT) 2007. Professional ed. Chicago, IL: AMA; 2007: 499.
8. Bolton C, Walker FO. Electromyography and nerve conduction study (EMG/NCS). Sensory nerve conduction study workshop. American Academy of Neurology, Annual Meeting, Workshop #250. Washington, DC: May 2, 1994; pp. 250-13 to 250-234.
9. England JD, Gronseth GS, Franklin G, et al. Distal symmetric polyneuropathy: A definition for clinical research.  Report of the American Academy of Neurology, the American Association of Neuromuscular and Electrodiagnostic Medicine (AAEN) and the American Academy of Physical Medicine and Rehabilitation. Neurology. 2005; 64:199-207.
10. Jablecki CK, Andary MT, Floeter MK, et al. American Academy of Neurology, America Association of Neuromuscular and Electrodiagnostic Medicine and the American Academy of Physical Medicine and Rehabilitation. Practice parameter: Electrodiagnostic studies in carpal tunnel syndrome. Neurology. 1993; 43(11):2404-2405.  Republished:  Neurology. 2002; 58(11):1589-1592.
11. Practice parameter: Electrodiagnostic studies in ulnar neuropathy at the elbow. Summary statement of the American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine and the American Academy of Physical Medicine and Rehabilitation. Neurology. 1999; 52:688-690.
12. Wilbourn AJ, Aminoff MJ. AAEE Minimonograph #32: The electrophysiologic examination in patients with radiculopathies. Muscle Nerve. 1998; 21(12):1621-1631.

Electromyography, Nerve Conduction Studies
Electrophysiological Studies
EMG/NCS
Nerve Conduction Studies, Electromyography
Nerve Conduction Velocity Studies

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