Latency of multifocal visual evoked potentials in nonoptic neuritis eyes of multiple sclerosis patients associated with optic radiation lesions.
OBJECTIVE
The aim of the study was to test the hypothesis that latency delay of multifocal visual evoked potentials (mfVEP) in nonoptic neuritis (NON) eyes of multiple sclerosis (MS) patients is related to retrochiasmal demyelinating lesions.


METHODS
A total of 57 MS patients with no history of optic neuritis at least in one eye, and 25 age- and sex-matched healthy controls was enrolled. Probabilistic tractography was used to reconstruct optic radiation (OR) fibers. The MS lesion volume within and outside of OR was calculated. Diffusion tensor imaging (DTI) indices were measured along OR fibers. The relationship of the mfVEP latency with OR lesions and DTI indices was examined.


RESULTS
Average mfVEP latency in the MS cohort was significantly delayed compared to controls (P < 0.0001). Of the patients, 77% demonstrated OR lesions. Axial, radial, and mean diffusivity were significantly abnormal in MS patients (P < 0.001). Partial correlation demonstrated significant association between mfVEP latency delay and OR lesion load. There was also significant correlation between MfVEP latency and OR DTI. Subgroup analysis revealed significantly higher correlations in patients without a history of ON in either eye compared to the fellow eye of patients with previous ON.


CONCLUSIONS
The findings of this study support our hypothesis that latency delay of the mfVEP in eyes of MS patients without previous ON is related to retrogenicular demyelinating lesions. Additionally, this study demonstrated that a previous episode of ON in the fellow eye may be a significant confounding factor, masking the relationship between the latency and OR lesions.
Department of Ophthalmology, University of Sydney, Sydney, Australia Department of Ophthalmology, King Saud University, Riyadh, Saudi Arabia.
Daniah
D
Alshowaeir
Concord Hospital, Sydney, Australia Department of Neurology, Royal North Shore Hospital, Sydney, Australia.
Con
C
Yiannikas
St. Vincent Hospital, Sydney, Australia.
Raymond
R
Garrick
Department of Neurology, Royal North Shore Hospital, Sydney, Australia.
John
J
Parratt
Brain and Mind Institute, University of Sydney, Sydney, Australia.
Michael H
MH
Barnett
Australian School of Advanced Medicine, Macquarie University, Sydney, Australia.
Stuart L
SL
Graham
Department of Ophthalmology, University of Sydney, Sydney, Australia Australian School of Advanced Medicine, Macquarie University, Sydney, Australia.
Alexander
A
Klistorner
D000328:Adult; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009103:Multiple Sclerosis / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D009443:Neuritis / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D009900:Optic Nerve / Q000473:pathology* / Q000528:radiation effects
latency delay; multifocal VEP; multiple sclerosis; optic radiation