Neurology
Clinical Services - Electromyography and Nerve Conduction (EMG)
Lab
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Services > Electromyography and Nerve Conduction (EMG) Lab
Electromyography Test
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Nerve Conduction Studies:
Left panel - normal
Center panel - ulnar neuropathy at the wrist
Right panel - severe ulnar neuropathy at the elbow |
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Electromyography is one of the major diagnostic tests for diseases
of nerve and muscle. This test actually consists of 3 parts:
The history and neurologic examination are performed first to
learn the nature of the problem, whether it is likely neurologic
or neuromuscular, to determine which nerves or muscles are most
affected, and to help focus the NCS and EMG. It generally takes
10 - 15 minutes.
Nerve Conduction Studies (NCS)
NCS are performed next and take about 30-45 minutes. While
lying down, surface electrodes are taped over several cutaneous
zones
and muscles. The nerves which supply those zones or muscles
are then stimulated with a surface probe and the resulting
electrical
responses are recorded by the surface electrodes which
are in turn attached to an EMG machine. The electrical responses
provide
detailed information about nerve function. These stimuli
feel like a small shock (as when touching a metal object
after walking
on a rug) and are almost always well tolerated.
Electromyography (EMG)
EMG is performed last and takes about 5 - 15 minutes. During
this test, a very small needle electrode (smaller than the needle
employed during a blood draw) is placed in one or more muscles
in the arm, leg or back. The electrical activity of the muscle
is fed back through the electrode to the EMG machine when the
muscle is at rest and then when it is voluntarily activated by
the patient. The electrical information obtained from EMG provides
precise information about muscle function. EMG may be slightly
painful, but only lasts several seconds per muscle. There is
no electrical stimulation during this part of the test.
Test Results
At the end of the study, the results of the neurologic examination,
the NCS and EMG are combined to reach a precise diagnosis.
A detailed report is produced and sent to the referring physician
within 48 hrs.
If you would like more information, call 585-275-4568.
Last updated 9/11/2006 JDF
