Normal findings in electromyogaphy.

Facilitating understanding of clinical neurophysiologic findings and interpretation in different nerve and muscle disorders by reviewing basic electromyography is the object of this talk. While a broader knowledge of nerve & muscle anatomy, neurophysiology, technique, electricity, and neuromuscular disease is required for more complete comprehension of this type of electrodiagnostic evaluation emphasis in brief will be on essential components of EMG studies particularly focusing on findings in normal conditions and patients. Electromyography (EMG) is a common shorthand label for the entire diagnostic evaluation including Nerve Conduction Studies (NCS/NCV). In NCS action potential recordings are elicited by transcutaneotis stimulation of nerves. The amplitude and conduction velocity measures obtained from sensory and motor potentials yields information that may reflect disease. The needle EMG examination has three main divisions during which muscular electrical activity is recorded and analyzed, including insertional activity, spontaneous activity, and voluntary motor unit activity, with different normal and abnormal results expected in each section. It is hoped that a highlight review of the basics will serve as an aid to better appreciation by the physician delegates of succeeding topics covered in this meeting. (Author)