The Visual Evoked Potential

The visual evoked potential (VEP) is a cortical potential elicited to afferent visual pathway stimulation. This chapter starts with describing the technology used for the VEP, specifically in regard to stimulus and recording considerations. This is particuarly relevant for those troubleshooting the VEP or considering technical requirements of a laboratory. The technique is thereafter discussed, to describe patient and recording factors which yield the best quality data for interpretation. The main section on clinical applications and interpretation of the VEP highlight the major principles for interpreting the VEP waveform, limitations of the VEP, and how testing strategies may be expanded or complemented with other electrophysiological tests to aid diagnostic certainty or clinical diagnosis. These sections follow into the ‘pearls and pitfalls’ section, which delve into more specific recording, interpretation and other clinical considerations which can occur with VEP and may be common sources for uncertainty. Overall it is emphasised how the VEP is an exceptionally valuable test in assessment of the visual pathway, alongwith adequate awareness of its strengths and weaknesses.