A nerve conduction study (NCS) is an important test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. It involves the process of applying small electrical impulses to a nerve and recording a response using an electrode. It is a slightly uncomfortable study but in no way harmful to the patient.
Mainly used in the evaluation of pareesthesias (sensory symptoms) and/or weakness of the peripheral nerves of the body. The studies conducted are dependent on the presentation of the symptoms.
Common referrals for nerve conduction studies include:
Motor NCS are performed by electrical stimulation of a peripheral nerve and recording from a muscle supplied by this nerve. The response is then recorded and different aspects of the response are analyzed, namely
Sensory NCS are performed by electrical stimulation of a peripheral nerve and recording from a purely-sensory portion of the nerve, such as on a finger. Like motor nerve conduction studies the latency, amplitude, and conduction velocity of the response are analyzed.
Is a supramaximal stimulation of a nerve. The study calculates the time it takes from point of stimulation to the anterior horn call and back to recording electrode.
Studies are interpreted by a neurologist. Responses are compared to normal values for specific nerves, and deviations in these values and compared to hallmarks of specific pathological processes.