49-2).Īll the SNAPs were normal except for the median nerve which had prolonged latency, slow conduction velocity, and mildly decreased amplitude suggesting a mild median neuropathy at the wrist. He also had evidence of partial conduction blocks ( Fig. The nerve conduction velocity (NCV) test showed all the features of demyelinating neuropathy with velocity slowing, temporal dispersion of the CMAPs, prolonged distal latencies and F-responses, and no H-reflexes. Bertorini MD, in Neuromuscular Case Studies, 2008 WHAT WERE THE EMG FINDINGS? Serial strength-duration testing therefore allows the clinician to assess neuromuscular recovery. 52 A denervated or partially denervated muscle requires more time and current than a normally innervated muscle. Electrical stimulation of motor points assesses the strength-duration curves of the affected muscles. This is a late reaction that potentially results from the backfiring of antidromically activated anterior horn cells. 51Īnother type of electrodiagnostic testing is the F response, an outgrowth of the measurement of velocity of conduction. Because anterior horn cell diseases and intervertebral disk protrusions do not influence nerve conduction latency, the clinician can be certain that a proximal nerve conduction delay is the result of a brachial plexus lesion. Nerve conduction velocity tests help to distinguish muscular weakness in the affected upper extremity from cervical intervertebral disk protrusion, anterior horn cell disease, or a brachial plexus lesion. Greenfield, Kathleen Geist, in Physical Therapy of the Shoulder (Fifth Edition), 2012 Nerve Conduction Studies A complete report on your nerve conduction study will be sent to the consultant that ordered the test.Bruce H. The technician may be able to tell you the results of the test before you leave. Nerve conductions studies are usually performed as an outpatient meaning you can go home the day of the test. The nerves in the opposite side of your body may also be tested for a comparison.

Don’t worry, the shocks are very small and should only produce a slight tingling sensation. The time it takes for the muscle to contract (tighten) is recorded. The electrodes are connected to a machine that can send electric signals to the areas and record the activity.ĭuring the test several electric shocks are produced via the electrodes. They will also place electrodes on the muscles supplied by the nerve. What happens during a nerve conduction study?Ī technician will place small pads with metal discs called electrodes over the nerve being tested.

It is often performed before an electromyography (EMG) to diagnose and treat conditions such as carpal tunnel syndrome, nerve injury or sciatica.

Nerve conduction test on neck