For every electrodiagnostic (EDX) test performed, one needs to decide if the study is normal or abnormal. That determination often needs to be made in real time as the testing progresses, so that the study can be modified based on…
Understanding and recognizing artifacts and technical factors play a central role in every nerve conduction and electromyography (EMG) study ( Box 8.1 ). The value of the information gained during an electrodiagnostic (EDX) study relies on two important and complementary…
Although peripheral nerve anatomy is more or less similar among individuals, in a sizable minority, there are some significant anatomic variations. These are known as anomalous innervations. Several of these anomalous innervations of peripheral nerve are commonly seen in the…
The use of repetitive nerve stimulation (RNS) dates to the late 1800s, when Jolly made visual observations of muscle movement that occurred after nerve stimulation. Although his initial studies were done with submaximal stimuli and mechanical rather than electrical measurements…
Few routine electrophysiologic tests are available to evaluate the cranial nerves and their proximal segments other than visual and brainstem-evoked potentials. However, cranial nerves V (trigeminal) and VII (facial), along with their connections in the pons and medulla, can be…
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…
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…
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,…
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),…
List of Abbreviation SCI Spinal cord injury Acknowledgements (in alphabetical order) We would like to thank the following authors for contributing to the development of this resource. We apologize if some suggested material was not included in this chapter or…