Nerve conduction studies: essentials and pitfalls in practice

A neurologist has sent a patient for nerve conduction studies (NCS) and has received the report, but what does it mean? We hope to remove some of the mysteries that may surround NCS. The techniques and how they are affected by disease are described in general terms. These principles can be applied to specific conditions discussed elsewhere. We also discuss the numerous pitfalls that may be encountered with NCS. Understanding these basic concepts will allow you to get the most from your clinical neurophysiology department. NCS are only part of a complete peripheral neurophysiological examination (PNE) and are frequently accompanied by a needle electromyogram (EMG). The combination of both techniques and those detailed in other articles in this issue are often required for a complete diagnostic study. The process of choosing the appropriate tests is the responsibility of the clinical neurophysiologist (CN) and not the referring doctor and is planned as a dynamic series of steps designed to answer specific questions about nervous system function raised by the clinical picture. Clinical neurophysiologists can employ a confusing number of terms and abbreviations. Box 1 lists the ones we use frequently. ### Box 1: List of abbreviations and terminology used