Many physicians will recommend an EMG/NCS
(electromyogram and nerve conduction study) for their patients with
tingling/numbers, or weakness in an extremity or extremities. The physician
hopes the EMG/NCS
test will assist them in determining the cause of the problem and to
aid in determining the best course of treatment and/or the need for
other tests. How can you tell you are getting a quality study with information
that will help you make an informed decision regarding your patient’s
care?
1. The EMG/NCS exam should be customized for the patient’s specific
complaints. To do this, the EMG/NCS clinician should address the referring
physician’s concerns based on the referral. Further, the EMG/NCS
provider should take a brief history and perform a neuromuscular screening
exam to know where to direct the study.
2. The EMG/NCS provider should perform both the NCS and the needle EMG.
The inclusion of the EMG exam is the only way to confirm the presence
of a nerve root injury (radiculopathy), determine chronicity, axonal
degeneration vs. just a neuropraxia, and assist in ruling out more serious
disease.
3. The interpretation should be written in pathophysiologic terms. For
example, instead of just providing a diagnosis of “carpal tunnel
syndrome,” the EMG/NCS clinician should state if there is just
myelin injury (neuropraxia) versus axonal injury, motor fiber versus
sensory fiber involvement, the severity of the problem, and in some cases,
the chronicity of the problem. In most entrapment neuropathies (like
CTS), patients with myelin involvement of the sensory fibers is a mild
problem compared to those with motor involvement (moderate), or those
with axonal injury (severe CTS).
Greg Ernst, PT, PhD, ECS has been performing and interpreting quality
EMG/NCV studies for over 19 years. He is board certified by the American
Board of Physical Therapy Specialties and is now providing these services
at the Boerne Physical Therapy Institute. Call 249-7211 to set up an
appointment. |