Nerve Conduction Study (NCS) is a test that evaluates the function of the peripheral nerves, measuring the speed of impulses as they travel along nerve pathways. NCS is a non-invasive test, using surface electrodes to provide electrical stimulation to the tested nerves.
NCS measures the speed, amplitude, and latency of nerve impulse transmission. Both motor and sensory nerves are evaluated. F-wave and H-reflex studies are also commonly performed. These are observations of the effects of nerve transmission on muscle.
NCS is useful in diagnosing both localized nerve dysfunction (e.g. carpal tunnel syndrome) and generalized dysfunction (e.g. peripheral neuropathy).
EMG and NCS are commonly performed together.