What is an EMG test?

AANEMElectromyogram (EMG) measures the response of muscles and nerves to electrical activity. It’s used to help determine muscle conditions that might be causing muscle weakness, including spine pain and problematic nerve disorders.

Who needs an EMG test? 
Individuals with general nerve and muscle problems – including pain, weakness, numbness, and stinging – often seek electrodiagnostic laboratories such as the one in the Spine and Pain Center at Northern Arizona Orthopaedics, to perform and read these specialized nerve conduction tests.

How Is an EMG Done?
Muscles are stimulated by signals from nerve cells called motor neurons. This stimulation causes electrical activity in the muscle, which in turn causes the muscle to contract or tighten. The muscle contraction itself produces electrical signals.

For the purpose of EMG, a needle electrode is inserted into the muscle (the insertion of the needle might feel similar to an injection). The signal from the muscle is then transmitted from the needle electrode through a wire (or more recently, wirelessly) to a receiver/amplifier, which is connected to a device that displays a readout. The results are either printed on a paper strip or, more commonly, on a computer screen.

What Can an EMG Diagnose?
EMGs help diagnose three kinds of diseases that interfere with normal muscle contraction:

  • Diseases of the muscle itself
  • Diseases of the neuromuscular junction, which is the connection between a nerve fiber and the muscle it supplies
  • Diseases “upstream” in nerves and nerve roots (which can be due to either nerve damage or ongoing nerve injury)

When Are Results Ready?
Results are available immediately but a trained medical specialist, such as a physiatrist/PM&R physician, is needed to analyze and interpret them. EMG tests are common and performed daily in the Spine and Pain Center at NAO.

Does it matter that I go to an Accredited Lab to have my EMG done?
Yes, if you want the best care. NAO’s EMG Lab was recently approved for Lab Accreditation, with an added level of Exemplary Status by the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM). This is the highest level of AANEM accreditation for any lab in the region. Statewide, there are only five other accredited labs in Phoenix and Tucson. This means patients needing an EMG have the highest-quality facility available to them in central and northern Arizona at Northern Arizona Orthopaedics.

Call 928-774-7757 to learn more or schedule a visit.