A nerve conduction study (NCS) is a medical diagnostic test commonly used to evaluate the function, especially the ability of electrical conduction, of the motor and sensory nerves of the human body. These tests are performed by medical specialists such as specialists in clinical neurophysiology, physiatrists (physical medicine and rehabilitation [PMR] physicians), and neurologists who subspecialize in electrodiagnostic medicine. In the United States, neurologists receive training in electrodiagnostic medicine (performing needle electromyography and NCSs) as part of residency training and in some cases acquire additional expertise during a fellowship in clinical neurophysiology, electrodiagnostic medicine, or neuromuscular medicine. PMR physicians receive this training during their residency and can get further training in a neuromuscular fellowship. Outside the US, clinical neurophysiologists learn needle EMG and NCS testing.