Electromyography and nerve conduction studies.

Electromyography and nerve-conduction studies are very useful tools in the evaluation of disease of peripheral nerve and muscle. They should be thought of as extensions of the physical examination. The tests should be used to answer specific questions and to help arbitrate diagnostic dilemmas. The tests, however, have very definite limitations. There are significant false-negative rates, and unexpected positive results can be misleading. The tests rely heavily on careful clinical-electrophysiological correlation.