What to Expect from the Electrodiagnostic Medicine Physician

The evaluation of patients with suspected polyneuropathy (subsequently referred to as “neuropathy”) is relatively straightforward, and consists of a combination of clinical, electrophysiologic, and laboratory studies. Evaluation of suspected neuropathy is among the most frequent investigations performed in the electromyography (EMG) laboratory. The electrodiagnostic (EDX) examination includes sensory and motor nerve conduction studies (NCSs), evaluation of late responses, and needle EMG (needle EMG). In clinically appropriate situations, autonomic testing should be performed to assess involvement of the parasympathetic and sympathetic fibers. Clinicians use the EDX evaluation as an extension of their neurologic examination to confirm clinical findings, localize abnormalities, and identify the underlying pathophysiology. A well-designed electrophysiological evaluation of a patient with neuropathy focuses the differential diagnosis, directs the subsequent laboratory evaluation, and often suggests a specific diagnosis or class of disorders.