The visual evoked potential (VEP) is primarily a relatively large, positive polarity wave generated in the occipital cortex in response to visual stimulation. It measures the conduction time of neuronal activity from the retina to the occipital cortex and is used clinically as a measure of the integrity and function of that pathway. The optic nerve is the primary structure examined. The standard VEP averages many responses, time-locked to a photic stimulus. Of primary interest is the latency of the positive wave at a midline occipital EEG electrode, usually at approx 100 ms after stimulation, called the P100. This chapter summarizes the methodology for recording the VEP, provides an approach to its interpretation, and discusses its role in clinical practice.
Key WordsEvoked potential visual optic nerve demyelination latency multiple sclerosis P100 optic chiasm occipital blindness
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