Comparison of multifocal visual evoked potential, standard automated perimetry and optical coherence tomography in assessing visual pathway in multiple sclerosis patients

Background: Multifocal visual evoked potentials (mfVEP) measure local response amplitude and latency in the field of vision. Objective: To compare the sensitivity of mfVEP, Humphrey visual field (HVF) and optical coherence tomography (OCT) in detecting visual abnormality in multiple sclerosis (MS) patients. Methods: mfVEP, HVF, and OCT (retinal nerve fiber layer [RNFL]) were performed in 47 MS-ON eyes (last optic neuritis [ON] attack >= 6 months prior) and 65 MS-no-ON eyes without ON history. Criteria to define an eye as abnormal were: (1) mfVEP amplitude/latency - either amplitude or latency probability plots meeting cluster criteria with 95% specificity; (2) mfVEP amplitude or latency alone (specificity: 97% and 98%, respectively); and (3) HVF and OCT, mean deviation and RNFL thickness meeting p < 0.05, respectively. Results: MfVEP (amplitude/latency) identified more abnormality in MS-ON eyes (89%) than HVF (72%), OCT (62%), mfVEP amplitude (66%) or latency (67%) alone. Eighteen percent of MS-no-ON eyes were abnormal for both mfVEP (amplitude/latency) and HVF compared with 8% with OCT. Agreement between tests ranged from 60% to 79%. mfVEP (amplitude/latency) categorized an additional 15% of MS-ON eyes as abnormal compared with HVF and OCT combined. Conclusions: mfVEP, which detects both demyelination (increased latency) and neural degeneration (reduced amplitude), revealed more abnormality than HVF or OCT in MS patients.