Multifocal visual evoked potential analysis of inflammatory or demyelinating optic neuritis.
OBJECTIVE
To determine the sensitivity of multifocal visual evoked potentials (mVEP) in optic neuritis of an inflammatory or demyelinating nature.


METHODS
Cross-sectional study.


METHODS
Sixty-four patients participated who had a confirmed diagnosis of optic neuritis (ON) (past and acute). Based on the McDonald multiple sclerosis (MS) criteria, 25 patients (27 eyes with ON) were deemed to have isolated optic neuritis and thus not have MS (i.e., the not-MS group), and 19 patients (24 eyes with ON) had a diagnosis of MS (i.e., the MS group). The remaining 20 patients (25 eyes with ON) were at a high risk of MS, but diagnostic evaluation was equivocal, and thus were classified as the possible MS group. A control group of 20 normal patients was enrolled.


METHODS
The mVEP test was performed using the Accumap. All ON patients had recent magnetic resonance imaging scans of the brain and spinal cord.


METHODS
Multifocal visual evoked potentials amplitude and latency values were analyzed within each group and were compared with the normal controls.


RESULTS
No abnormality was recorded on mVEP in the control group. Of all the ON eyes, 74 (97.3%) were abnormal on mVEP testing. Amplitude values were abnormal in 92.6% of not-MS eyes, 92.0% of possible MS eyes, and 100% of those with MS, and latency was abnormal in 33.3%, 76.0%, and 100%, respectively. There was a significant difference in the mVEP latency z-scores among all ON groups (P<0.01; Kruskal-Wallis test). Although distribution graphs of latency z-scores in the not-MS and MS groups had single peaks and were clearly separate from each other, the latency z-score distribution within the possible MS group in postacute patients was bimodal, with each peak corresponding to the distribution of the not-MS and MS group, respectively. The mVEP latency z-scores had a sensitivity and specificity of 100% in detecting patients with ON due to MS when compared with normal patients.


CONCLUSIONS
The mVEP test is a sensitive and specific tool for detecting optic neuritis. There was a significant difference in latency analysis findings between patient groups as classified according to the McDonald MS criteria. Latency results suggest a role in identifying a patient's risk for future MS.
Fraser
Clare L
CL
Department of Electrophysiology, Save Sight Institute, University of Sydney, Sydney, NSW, Australia. clare@eye.usyd.edu.au
Klistorner
Alexander
A
Graham
Stuart L
SL
Garrick
Raymond
R
Billson
Francis A
FA
Grigg
John R
JR
D000208:Acute Disease; D000328:Adult; D003430:Cross-Sectional Studies; D005074:Evoked Potentials, Visual; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage; D009103:Multiple Sclerosis / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D009902:Optic Neuritis / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D020551:Pulse Therapy, Drug; D012372:ROC Curve; D012680:Sensitivity and Specificity
D005938:Glucocorticoids; D008775:Methylprednisolone