The purpose of this study was to evaluate multifocal visual evoked potential (mfVEP) and pattern-reversal visual evoked potential (PVEP) changes in patients with pathology at various levels of the visual pathway determined by other methods. Six patients with different visual pathway disorders, including vascular ischaemic events and compressive optic neuropathy, were reviewed. All patients were tested with both mfVEP and full-field and half-field PVEPs. Results were assessed in relation to other diagnostic tests such as magnetic resonance imaging, Humphrey visual field test, and optical coherence topography. The cases in this study demonstrate a potential higher sensitivity of mfVEP compared with conventional PVEPs in detecting lesions affecting the peripheral field, horizontal hemifields, and lesions of the post-chiasmal pathway. The limitation of the PVEP in this setting is probably due to phase cancellation and overrepresentation of the macular region. mfVEP provides a more accurate assessment of visual defects when compared with conventional PVEP. The independent assessment of different areas of the visual field improves the detection and localization of lesions and provides an objective topographical map that can be used in clinical practice as an adjunct to other diagnostic tests and to assess disease progression.
Keywords: Multifocal VEP; visual evoked potential; visual pathway.