Pattern reversal VEPs in optic neuritis:Advantages of central and peripheral half-field stimulation

Abstract

Patients who had had attacks of optic neuritis and whose VEPs showed ‘scotoma-tous’ waveforms in routine 0-16° r half-field testing, were examined in more detail with central (0-4° r) and peripheral (4-16° r) half-field stimulation in order to more reliably identify macularly (P100) and paramacularly (P135) derived components. It was found that this more elaborate testing was helpful in the interpretation of ‘scotomatous’ features, as it clarifies the nature of the predominant positive component. In those 0-16°r half-field records where only a single positivity could be discerned, central and peripheral stimulation revealed that this positivity was either the paramacular P135 component or had joint contributions from both macular P100 and paramacular P13S components. In other 0-16°r half-field records, where two positivities (P100 and P135) were distinguished, P100 was commonly reduced and component P135 was enhanced. Stimulation of the central field confirmed that the PI00 component was attenuated in these cases.

Key Words:

• pattern reversal VEP
• half-field stimulation
• central and peripheral stimulation
• identification of VEP components
• multiple sclerosis and optic neuritis