Clinical neurophysiology is a medical specialty that studies the central and peripheral nervous systems through the recording of bioelectrical activity, whether spontaneous or stimulated. It encompasses both research regarding the pathophysiology along with clinical methods used to diagnose diseases involving both central and peripheral nervous systems. Examinations in the clinical neurophysiology field are not limited to tests conducted in a laboratory. It is thought of as an extension of a neurologic consultation. Tests that are conducted are concerned with measuring the electrical functions of the brain, spinal cord, and nerves in the limbs and muscles. It can give the precise definition of site, the type and degree of the lesion, along with revealing the abnormalities that are in question. Due to these abilities, clinical neurophysiology is used to mainly help diagnose diseases rather than treat them.

In some countries it is a part of neurology or psychiatry, for example the United States and Germany. In other countries it is an autonomous specialty, such as Spain, Portugal, Italy, the United Kingdom, Finland, Sweden and Norway.

Hospitals that have neurologists and neurosurgeons tend to house clinical neurophysiology departments. Usually these tend to be larger hospitals that are able to employ more specialized staff units. In hospitals that possess clinical neurophysiology facilities, the major diagnostic modalities employed include:

• Electromyography and nerve conduction studies: These diagnostic tests of the peripheral nervous system, especially useful in evaluating diseases of the muscles, nerves, and nerve roots. Records electrical activity of the muscles and the passage of them along nerves in the limbs. Most nerve-muscle disorders that occur fall into one of two types of categories, morphologic or physiologic, which can be seen within the motor unit. These disorders can either be acute, or have a slow developing nature. An online tool that allows the interactive exploration of these neurophysiological methods and of symptoms to which they are related can be found here.
• Electroencephalography: Diagnostic test of thalamocortical rhythms (brain waves), useful in evaluating seizures and various abnormalities of the central nervous system. This is done by hooking up electrodes on the surface of the scalp to record currents from the cerebral cortex.
• Evoked potentials: Diagnostic test evaluating specific tracts of the central and peripheral nervous system. May include visual, auditory, or somatosensory evoked potentials. These record the electrical responses of the brain and spinal cord to the stimulation of the senses.
• Polysomnography: A type of sleep study employed to diagnose disorders associated with abnormal sleep behavior
• Intraoperative monitoring, Intraoperative neurophysiologic monitoring: