Evoked potential instrumentation, methodology and theory.

Evoked potentials are the electrical potentials of the nervous system which can be evoked by brief stimulations with lights, noises, or other means. Testing for these has become routine in certain settings in neurology. A wide variety of types of such tests are available. The technique usually involves stimulation of the patient with a standardized light, earphones or nerve stimulator. Recordings are taken from the scalp or other sites, and averaged over many separate stimulations. A good working knowledge of the equipment is needed for proper recording and interpretation of these tests. This article reviews the instrumentation, methods and theory behind clinical evoked potentials.