What the study looks at
Surface electrodes record the nerve’s response to a brief electrical stimulus. A motor study records the muscle response after the nerve to that muscle is stimulated. A sensory study records the signal from a sensory nerve.
The recording is described by three main measurements: how long the signal takes to travel (latency), how large the response is (amplitude), and, when the nerve is stimulated at two sites, how fast it conducts between those sites (conduction velocity). Limb temperature affects these numbers, so a careful study accounts for it.
Nerves commonly included, depending on the question, are the median, ulnar, and radial nerves in the arm, and the peroneal, tibial, and sural nerves in the leg.
How the visit is performed
The patient is seated or lying down. Electrodes rest on the skin over the nerve and, for a motor study, over the muscle. Each stimulus is a short pulse. It feels like a tap or a brief buzz. The number of nerves depends on the referring question, so a focused study of one entrapment takes less time than a broader neuropathy survey.
Atlas brings the equipment and a technician to the physician’s office. The study does not require the patient to go to a hospital lab.
Why a practice orders it
Physicians request nerve conduction studies when they are evaluating a possible peripheral nerve problem. Common reasons include entrapment, such as carpal tunnel syndrome or ulnar neuropathy at the elbow, a more widespread neuropathy, or nerve injury after trauma.
Paired with EMG, the two studies help separate a problem in the nerve from a problem in the muscle, and they can help localize where along the nerve the change is. The numbers do not diagnose a patient on their own. The referring physician interprets them with the history and exam.