Nerve Conduction Studies
DESCRIPTION
Nerve conduction studies (NCS) are performed to diagnose diseases of, and the integrity of, the peripheral nervous system. Results may indicate that sensory symptoms are due to an impairment of peripheral nerve function or, when normal, to a lesion proximal to the dorsal root ganglia. Nerve conduction studies assess the speed (conduction velocity, and/or latency), size (amplitude), and shape of the response. Pathological findings include conduction slowing, conduction block, no response, and/or low amplitude response. Nerve conduction study results can assess the degree of demyelination and axon loss in the segments of the nerve studied.
POLICY
Nerve conduction studies for the diagnosis of motor neuron diseases, myopathies, radiculopathies, plexopathies, neuropathies and neuromuscular junction (NMJ) disorders (e.g., myasthenia gravis, myasthenic syndrome) are considered medically necessary.
Because valuable diagnostic data is obtained with needle electromyography, nerve conduction velocity studies performed without needle electromyography studies, unless contraindicated (e.g. an individual is receiving anticoagulant therapy), are considered investigational.
Automated, hand-held, non-invasive nerve conduction testing (e.g., NC-statŪ) is considered investigational.
Any device utilized for this procedure must have FDA approval specific to the indication, otherwise it will be considered investigational.
See also:
ADDITIONAL INFORMATION
Nerve conduction studies are to be performed by the physician alone or by a technologist under direct supervision of the electrodiagnostic (EDX) consultant. The consultant must be trained or certified in the application, performance and interpretation of electrodiagnostic testing and licensed by the state in which the studies are performed. The technician performing the studies must be trained in electrodiagnostic testing and licensed or certified by the state (or by one of the state's health related boards if licensure or certification as a technician does not exist in a given state) in which the studies are performed. Electrodiagnostic testing is not performed in a standard fashion, but must be specifically designed for each individual patient. It is often necessary to modify or add to the procedure during the examination, depending on the findings as they unfold. For this reason, collection of the clinical and electrophysiologic data must be entirely under the supervision of an EDX consultant who is physically present in the facility in which the studies are performed and actively involved in the examination of the findings as they unfold. (Refer to BCBST's Staff Supervision Requirements for Delegated Services policy.)
The decision to perform an NCS must be based upon a history and physical examination findings obtained prior to the performance of the procedure and evident in the individual's record.
In order to perform and interpret electrodiagnostic tests, it is the position of the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) that, the EDX consultant be a physician who has had special training in the diagnosis and treatment of neurological and neuromuscular diseases and in the application of particular neurophysiologic techniques to the study of these disorders. This type of training is generally included in the residency or fellowship programs of physicians who specialize in physical medicine and rehabilitation (physiatrists) or neurology (neurologists). Current interpretation of the Committee on Electrodiagnosis of the American Chiropractic Association Council on Neurology is that electrodiagnostic evaluation/interpretation in the assessment of neurological disorders should be performed by a board eligible or board certified Chiropractic Neurologist.
A typical NCS examination includes the following:
Development of a differential diagnosis by the EDX consultant based upon appropriate history and physical examination.
NCS of a number of nerves by recording and studying the electrical responses from peripheral nerves or the muscles they innervate, following electrical stimulation of the nerve. Usually surface electrodes are used for both stimulation and recording, though needle electrodes may be required in special cases.
Completion of indicated needle EMG studies to evaluate the differential diagnosis and to complement the nerve conduction studies. The use of invasive needle electrodes requires the skill of a trained EDX consultant who is a MD or a DO.
Motor, sensory and mixed nerve conduction studies and late responses (F-waves and H-reflex studies) are frequently complementary and performed during the same evaluation.
Automated, non-invasive nerve conduction equipment does not meet the following technology evaluation criteria:
The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes.
The technology must improve the net health outcome.
The technology must be as beneficial as any established alternatives.
The improvement must be attainable outside the investigational settings.
SOURCES
American Association of Neuromuscular & Electrodiagnostic Medicine. (2004, June). Recommended policy for electrodiagnostic medicine. (Endorsed by the American Academy of Neurology and American Academy of Physical Medicine and Rehabilitation.) Retrieved October 30, 2006 from http://www.aanem.org/documents/recpolicy.pdf.
American Association of Neuromuscular & Electrodiagnostic Medicine. (1999, May). Who is qualified to practice electrodiagnostic medicine? Position Statement. Retrieved December 16, 2003 from http://www.aanem.org/practiceissues/positionstatements/Who%27s_Qualified.cfm.
American Association of Neuromuscular & Electrodiagnostic Medicine. (1998, February). Responsibilities of an electrodiagnostic technologist. Position Statement. (Endorsed by the American Association of Electrodiagnostic Technologists August 1998.) Retrieved December 16, 2003 from http://www.aaem.net/aaem/PracticeIssues/PositionStatements/responsibilities_of_an_EDXTech.cfm.
American Association of Neuromuscular & Electrodiagnostic Medicine. (2000, February). Job description of electrodiagnostic technologists. Position Statement. (Endorsed by the American Society of Electroneurodiagnostic Technologists April 2000.) Retrieved October 30, 2006 from http://www.aanem.org/documents/job_descriptions_edxtech.pdf.
American Association of Neuromuscular & Electrodiagnostic Medicine. (2006, March). Proper performance and interpretation of electrodiagnostic studies. Position Statement. Retrieved November 3, 2006 from http://www.aanem.org/documents/ProperPerformance.pdf.
American Association of Neuromuscular & Electrodiagnostic Medicine. (1999, May). Technologists conducting nerve conduction studies and somatosensory evoked potential studies independently to be reviewed by a physician at a later time. Position Statement. Retrieved December 16, 2003 from http://www.aanem.org/documents/techs_conducting_ncs_sep.pdf.
CIGNA HealthCare Medicare Administration. Medicare Part B Carrier - Tennessee Local Medical Review Policy. (2006, October). LMRP for nerve conduction studies (NCS) electromyography (EMG) (L5789). Retrieved October 30, 2006 from http://www.cms.hhs.gov/mcd/viewlcd.asp?lcd_id=5789&lcd_version=29&show=all.
Goetz, C. G., (Ed.). (2003). Textbook of Clinical Neurology (2nd ed., pp. 481-482). St. Louis: W. B. Saunders Company.
Katz, R. T. (2006). Nc-stat as a screening tool for carpal tunnel syndrome in industrial workers. Journal of Occupational and Environmental Medicine, 48 (4), 414-418. Abstract retrieved October 30, 2006 from http://www.joem.org/pt/re/joem/abstract.00043764-200604000-00011.htm;jsessionid=FLZVG23hlDVJGzQh1tDdYpWhWN6RYy1SGB2hHkFSTsvdlzxByS68!-1434154485!-949856145!8091!-1
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EFFECTIVE DATE |
4/12/2007 |
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