New Jersey Chiropractic Council on Neurology

Pain of localized origin is treated differently than pain of a radicular origin.  Differential diagnosis includes radiculopathy, plexopathy neuropraxia, axonal degeneration or peripheral nerve entrapment.  Failure to diagnose may lead to erroneous treatment, diagnosis, and unnecessary extended care or inappropriately delayed referral.

In 1973, Upton and McCombs found cervical nerve root lesions in 70% of 115 patients with carpal tunnel syndrome or lesions of the ulnar nerve above the elbow.  They thought that this association was not fortuitous, but rather the result of serial constraints of axoplasmic flow in nerve fibers. They termed this combination double crush syndrome.  Yu et al found 20% of 525 patients with carpal tunnel syndrome had other neurologic disorders.  The associated disorders consisted primarily of involvement of the cervical roots, (53%), the ulnar nerve at the elbow, (28%), or both, (9%).  Nakano further stated that this responds only if treatment is directed toward both processes, and that electrodiagnostic and X ray studies should be performed in patients with entrapment neuropathy with symptoms referable to the neck.

Where needle EMG testing tests for end organ atrophy/muscle wasting associated with denervation, NCV testing tests the actual nerve itself, for neuropraxis and various compartment syndromes, i.e.: Carpal Tunnel Syndrome, etc.  Although the tests throughout history have been combined, the tests are mutually exclusive and test different things.  There is no medical logic that they must be combined and have only been done so through routine.  EMG only serves to uncover motor loss, by detecting atrophy of the innervated muscle tested.  Should the loss be sensory only, and not have progressed to the point of motor loss, the test is non-informative.  NCV testing uncovers any lesions to the peripheral nerve, as well as localizes the site of the lesion as well as the severity of the lesion.  This cannot be detected trough needle EMG testing.

DSEP is a sensory test that is non-invasive, and non-painful, (unlike EMG), which is much more useful in demonstrating a sensory radiculopathy that has not manifested itself as a motor neuropathy.  DSEP would uncover this type of lesion easily, which would be missed with EMG.

There is no clinical literature to support the statement that nerve conduction studies performed without electromyography are of little or no value.  As they are two separate and distinct tests that have been done together out of routine rather than out of medical necessity or rationale, the statement is invalid and has no place in medical determination of necessity.

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