Nerve conduction studies are most often used to assess distal nerve segments, with routine stimulation seldom done above the elbow or knee. Few studies can be easily performed to assess the more proximal nerve segments (plexus and roots). In the arm, surface stimulation can be performed proximally in the axilla and at Erb’s point, although technical factors limit these studies, especially at Erb’s point. Needle stimulation…

After the history is taken and a directed physical examination is performed, every study begins with nerve conduction studies (NCSs). The needle electromyography (EMG) examination is performed after the NCSs are completed because the findings on the NCSs are used in the planning and interpretation of the needle EMG examination that follows. Peripheral nerves usually can be easily stimulated and brought to action potential with a…

The electromyographer need not have detailed knowledge of all the electrical and chemical events that occur at a molecular level to perform an electrodiagnostic (EDX) study. However, one must have a basic understanding of anatomy and physiology to plan, perform, and properly interpret an EDX study. In the everyday evaluation of patients with neuromuscular disorders, nerve conduction studies (NCSs) and electromyography (EMG) serve primarily as extensions…

Electrodiagnostic (EDX) studies play a key role in the evaluation of patients with neuromuscular disorders. In selected cases, the additional use of neuromuscular ultrasound (U/S) can add key complementary anatomical and diagnostic information. EDX studies include nerve conduction studies (NCSs), repetitive nerve stimulation, late responses, blink reflexes, and needle electromyography (EMG), in addition to a variety of other specialized examinations. NCSs and needle EMG form the…