Evoked potentials are used to measure the electrical activity in certain areas of the brain and spinal cord. Electrical activity is produced by stimulation of specific sensory nerve pathways. These tests are used in combination with other diagnostic tests to assist in the diagnosis of neurological disorders

VISUAL EVOKED POTENTIALS: WHAT ARE THEY?
VEPs provide a sensitive indication of abnormal conduction in the visual pathway. Increases in retino-striate conduction time caused by processes such as demyelination can be detected by measuring the latency of this cortical response. Abnormalities in the amplitude and waveform of the VEPs may also be caused by the loss of axons in the pathway. VEPs are therefore widely used in the investigation of demyelinating disease, optic neuritis, and other optic neuropathies.

Brainstem auditory evoked potentials (BAEPs)
Brainstem auditory evoked potentials (BAEPs) are electrical field potentials generated by stimulation of the auditory pathways. With repetitive auditory stimulation, reproducible electrical potentials can be elicited and recorded from scalp electrodes. These waves are generated by specific brain regions and occur at predictable intervals. Clinically, this neurophysiological property is useful to evaluate the integrity of auditory pathways (plus, by extension, neighboring CNS structures) and to localize defective transmission. This chapter summarizes the methodology and clinical application of BAEPs in the investigation of disorders affecting auditory pathways and the surrounding brainstem

Somatosensory evoked response (SSER) test.
This test can detect problems with the spinal cord that cause numbness of the arms and legs. For this test, a healthcare professional attaches electrodes to your wrist, the back of your knee, or other locations. He or she will apply a mild electrical stimulus through the electrodes. Electrodes on your scalp then determine the amount of time it takes for the current to travel along the nerves to the brain.