Overview of Electrodiagnostic Services (EDX)
Electrodiagnostic studies play a key role in the evaluation of patients with disorders of nerve and muscle. The need for specific medical and surgical intervention may be determined based on the results of the EDX examination. Generally a two-part study, the EDX includes nerve conduction studies and needle electromyography. It is important to understand that the EDX study is an extension of the clinical examination.
Patients are frequently referred for EDX testing with complaints of muscle pain, numbness and tingling, neck pain, back pain, muscle weakness and muscle cramps. Follow up electrodiagnostic studies are generally not required, but are occasionally performed to assess progression of disease or to monitor recovery. The EDX study may diagnose disorders of peripheral nerve including carpal tunnel syndrome and other mononeuropathies, peripheral polyneuropathy, radiculopathy, myopathies and motor neuron disease.
An electromyogram (EMG) measures electrical activity in muscles using electrodes and a recording instrument. A specially trained neurologist, physiatrist or certified clinician places a tiny needle electrode into the muscle, recording electrical activity while the muscle is still and while the muscle is moving. The information helps physicians identify injuries related to muscles and nerves.
Nerve Conduction Studies
Healthy nerves send electrical signals called impulses to move muscles, but when nerves are damaged, they can cause tingling, numbness, pain and problems with muscle movement. Conduction studies guage how well a nerve is doing its job by targeting the nerve with low-level electrical pulses and measuring the muscle's reaction. One electrode is placed on the skin above the nerve, and a second is placed above the muscle controlled by that nerve. Surface electrodes are small, round devices about the size of a nickel that sit on the skin.
EDX Conditions Screened
- Amyotrophic lateral sclerosis (ALS)
- Carpal tunnel syndrome
- Pinched spinal nerves
- Motor neuron disease
- Muscle diseases
- Myasthenia gravis
- Tingling, numbness, muscle pain, weakness or cramps
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