Purpose of Review: This article provides core information on the clinical neurophysiology techniques available for the investigation of disorders of the peripheral nervous system.

Recent Findings: The role of small fiber dysfunction in some types of polyneuropathy is being increasingly appreciated, and neurophysiologic techniques for evaluating the autonomic components of peripheral axons have enhanced our understanding of small fiber dysfunction.

Summary: The principles of nerve conduction studies and needle EMG are presented in this article, along with the patterns of abnormality encountered in patients with polyneuropathy due to large and small fiber involvement.

Address correspondence to Dr John C. Kincaid, Department of Neurology, Indiana University School of Medicine, 355 W 16th St, Ste 4700, Indianapolis IN 46202, [email protected].

Relationship Disclosure: Dr Kincaid has provided expert medical testimony in neurologic legal cases for Social Security administrative law judges and has received research/grant support from Ionis Pharmaceuticals, Inc. Dr Kincaid receives publishing royalties from Wolters Kluwer and Demos Medical Publishing.

Unlabeled Use of Products/Investigational Use Disclosure: Dr Kincaid reports no disclosure.