Serial visual evoked potentials in 90 untreated patients with acute optic neuritis

Optic nerve topography in multiple sclerosis diagnostic criteria: Existing knowledge and future directions

Current diagnostic criteria for multiple sclerosis (MS) do not consider the optic nerve as a typical topography for establishing the diagnosis. Recent studies have proved the utility of optic nerve magnetic resonance imaging, optical coherence tomography and visual evoked potentials in detecting optic nerve lesions during the early stages of MS. In addition, emerging evidence supports the inclusion of optic nerve topography as a fifth region to fulfil the dissemination in space criteria. Anticipating a modification in the McDonald criteria, it is crucial for neurologists to familiarize with the diagnostic properties of each test in detecting optic nerve lesions and understand how to incorporate them into the MS diagnostic process. Therefore, the objective of this article is to review the existing evidence supporting the use of these tests in the diagnostic process of MS and provide a practical algorithm that can serve as a valuable guide for clinical practice.

Adding the Optic Nerve in Multiple Sclerosis Diagnostic Criteria: A Longitudinal, Prospective, Multicenter Study

BACKGROUND AND OBJECTIVES

The optic nerve is not one of the areas of the CNS that can be used to demonstrate dissemination in space (DIS) within the 2017 McDonald criteria for the diagnosis of multiple sclerosis (MS). Objectives were (1) to assess whether optic nerve-MRI (ON-MRI), optical coherence tomography (OCT), and visual evoked potentials (VEP) detect optic nerve involvement in clinically isolated syndrome (CIS) and (2) to evaluate the contribution of the optic nerve topography to the current diagnostic criteria in a prospective, multicenter cohort.

METHODS

MAGNIMS centers were invited to provide prospective data on patients with CIS who underwent a visual assessment with at least 2 of 3 investigations (ON-MRI, OCT, or VEP) within 6 months of onset. Modified DIS criteria were constructed by adding the optic nerve topography, defined by each investigation separately and any combination of them, as the fifth area of the CNS. A risk assessment analysis and the performance of the different DIS criteria were analyzed using the diagnosis of MS according to the 2017 McDonald criteria as the primary outcome and new T2 lesions and/or a second relapse as the secondary outcome.

RESULTS

We included 157 patients with CIS from 5 MAGNIMS centers; 60/157 (38.2%) patients presented with optic neuritis. Optic nerve involvement on ON-MRI was found in 40.2% patients at study entry and in 72.5% of those with optic neuritis.At follow-up (mean 27.9 months, SD 14.5), 111/157 patients (70.7%) were diagnosed with MS according to the 2017 McDonald criteria. Fulfilling either 2017 DIS or any modified DIS criteria conferred a similar high risk for reaching primary and secondary outcomes. The modified DIS criteria had higher sensitivity (92.5% [with ON-MRI] vs 88.2%), but slightly lower specificity (80.0% [with GCIPL IEA ≥4 μm] vs 82.2%), with overall similar accuracy (86.6% [with ON-MRI] vs 86.5%) than 2017 DIS criteria. Consistent results were found for secondary outcomes.

DISCUSSION

In patients with CIS, the presence of an optic nerve lesion defined by MRI, OCT, or VEP is frequently detected, especially when presenting with optic neuritis. Our study supports the addition of the optic nerve as a fifth topography to fulfill DIS criteria.

Visual Evoked Potentials for the Detection of Diabetic Retinal Neuropathy

Visual evoked potentials (VEP) are visually evoked signals that extract electroencephalographic activity in the visual cortex that can detect retinal ganglion cells, optic nerves, chiasmal and retrochiasmal dysfunction, including optic radiations, and the occipital cortex. Because diabetes causes diabetic retinopathy due to microangiopathy and neuropathy due to metabolic abnormalities and intraneural blood flow disorders, assessment of diabetic visual pathway impairment using VEP has been attempted. In this review, evidence on the attempts to assess the visual pathway dysfunction due to abnormal blood glucose levels using VEP is presented. Previous studies have provided significant evidence that VEP can functionally detect antecedent neuropathy before fundus examination. The detailed correlations between VEP waveforms and disease duration, HbA1c, glycemic control, and short-term increases and decreases in blood glucose levels are evaluated. VEP may be useful for predicting postoperative prognosis and evaluating visual function before surgery for diabetic retinopathy. Further controlled studies with larger cohorts are needed to establish a more detailed relationship between diabetes mellitus and VEP.

New, diagnostic flicker test for optic neuritis shows specific stages following disease onset

BACKGROUND

Previously, results of the digital flicker test (DFT) have shown distinct patterns in acute optic neuritis (ON) and healthy eyes. We aimed to examine the diagnostic potential of the DFT in acute ON and to investigate the temporal development of the DFT response following ON while comparing with visual evoked potentials (VEP).

METHODS

The DFT examines the subjective brightness of a flickering field, varied in 11 different frequencies from 0 to 60 Hz, compared to a steady field. Previous studies have indicated a pronounced darkness enhancement at medial frequencies in acute ON eyes. Darkness enhancement at medial frequencies was expressed as a quantitative covariate (DFT_DE). Results were compared with healthy controls and follow-up measurements were compared with VEP.

RESULTS

112 patients were examined <31 days of onset (median 14.0 days (IQR:12.25)). 104 of 112 patients showed an abnormal flicker test (sensitivity 93%). DFT was abnormal in 2 of 55 healthy controls. The DFT showed normalization in 34% at 3 months, 36.4% at 6 months and 71.4% at >8 months from ON onset compared to 13.3%, 22.4% and 28.6% for VEP. Changes to the pattern of the DFT results were shown at specific stages during and following ON.

CONCLUSIONS

The DFT is an easy-to-use and sensitive diagnostic test for acute ON. The flicker test shows a more pronounced temporal evolution following ON than VEP and may be of use monitoring the course of ON.

Different visual evoked potentials in neuromyelitis optica spectrum disorder-related optic neuritis and idiopathic demyelinating optic neuritis: a prospective longitudinal analysis

Background

To investigate different visual evoked potential (VEP) patterns in neuromyelitis optica spectrum disorder-related optic neuritis (NMOSD-ON) and idiopathic demyelinating optic neuritis (IDON).

Methods

This was a longitudinal, prospective, case-control study. Eighty-four Chinese patients with acute optic neuritis were enrolled, including 26 NMOSD-ON patients and 58 IDON patients. All the patients underwent best-corrected visual acuity (BCVA) and full-field pattern reversal VEP recordings at the onset, 1 month, 3 months, and 6 months.

Results

Within 15′ checks, the NMOSD-ON patients had more severe VEP amplitude reduction at 6 months (2.39 ± 4.63 μV vs. 6.96 ± 8.88 μV, P = 0.034). However, the IDON patients showed more frequently normal VEP response at 3 months (24.0% vs. 4.5%, P = 0.017), and only prolonged P100 peak latency with normal amplitude (L) at 6 months (30.0% vs. 57.8%, P = 0.048). Within 60′ checks, no significant difference in VEP parameters between the two groups was found at each follow-up (P > 0.05).

Conclusions

The NMOSD-ON patients showed more severe axonal damage and worse axonal recovery than the IDON patients. VEP elicited by smaller check size was more sensitive to visual pathway abnormality in NMOSD-ON.

Comparison of Visual Evoked Potentials in Patients Affected by Optic Neuritis From Multiple Sclerosis or Neuromyelitis Optica Spectrum Disorder

PURPOSE

To compare the visual evoked potentials (VEPs) of optic neuritis (ON) patients with multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and controls. To evaluate correlations between VEP and optical coherence tomography (OCT), contrast sensitivity (CS), and automated perimetry.

METHODS

Fifty-five eyes with ON from 29 patients (MS = 14 and NMOSD = 15) and 57 eyes from 29 controls were evaluated using VEP, automated perimetry, CS, and optical coherence tomography. Three groups were analyzed: 1) MS eyes with history of ON (ON-MS), 2) NMOSD eyes with ON (ON-NMOSD), and 3) healthy controls. Groups were compared and associations between the parameters were tested.

RESULTS

Compared to controls, ON-MS eyes showed significantly delayed N75 and P100 latencies when using a medium-sized stimulus (30'), and delayed P100 latency when using a large stimulus (1.5°), but similar amplitudes. Compared to controls, ON-NMOSD eyes showed significantly lower N75/P100 amplitudes (both stimulus sizes) and P100/N135 amplitudes (with the 30' stimulus), but latencies did not differ, except for a delayed P100 latency with the 30' stimulus. When comparing the 2 ON groups using the 1.5° stimulus, there was significant delay in P100 latency in ON-MS eyes and a reduction in N75/P100 amplitude in ON-NMOSD eyes. Peripapillary retinal nerve fiber layer, macular inner retinal layers, and CS measurements were significantly smaller in ON patients than in controls. A strong correlation was found between VEP parameters and inner retinal layer thickness in ON-NMOSD eyes.

CONCLUSIONS

ON-MS eyes had normal amplitude and delayed VEP latency, whereas ON-NMOSD eyes displayed reduced amplitude and preserved latency when elicited by checkerboard stimulus with large 1.5° checks. Under such conditions, VEP may help distinguish resolved MS-related ON from resolved NMOSD-related ON.

Visual Evoked Potentials in Neuromyelitis Optica Spectrum Disorders

Background

Neuromyelitis optica spectrum disorders (NMOSDs) are rare antibody-mediated disorders of the central nervous system, with a predilection for the spinal cord and optic nerves. The clinical utility of evoked potential recordings (EPs) has already been established for multiple sclerosis, in particular, that of the abnormal visual evoked potentials (VEP), a key criterion in the McDonald diagnostic criteria for MS. However, there have been few reports on EPs in patients with NMOSD.

AIM

The aim of our study was to assess the possible involvement of the optical pathway through VEP responses in patients with NMOSD.

Methods

VEPs were prospectively performed in 13 patients with NMOSD. All the patients were recruited from the outpatient clinic of a demyelinating diseases center. The recording was done as recommended by the International Federation of Clinical Neurophysiology.

Results

We evaluated the eyes of 12 women with a mean age of 42 years and of one man who was 25 years old. In 6 of the examined eye samples, a response was not obtained, while in the remaining 20 eye samples, we found a significant increase in P100 latency without amplitude change.

Conclusion

VEPs showed a significant increase in P100 latency. VEP assessment is a non-invasive, painless, fast, and low-cost exam that provides neurophysiological data for diagnosis of NMOSD.

Multifocal Visual Evoked Potentials (mfVEP) for the Detection of Visual Field Defects in Glaucoma: Systematic Review and Meta-Analysis

Some discrepancies have been observed in the diagnostic efficacy of multifocal visual evoked potential (mfVEP) when evaluating visual field defects in glaucoma patients. Therefore, we evaluated the diagnostic precision of the mfVEP in glaucoma to find its best diagnostic indicator. A systematic review and meta-analysis of quantitative studies published up to 1 April 2021 was performed. The methodological quality of the included articles was assessed. Publication bias analysis and heterogeneity tests were performed. The sensitivity, specificity and diagnostic odds ratio were calculated. The area under the curve (AUC) was calculated using the summary of receiver operating characteristics curve. Six studies with a total of 241 patients were included according to the inclusion and exclusion criteria. The AUC was 0.98. There was no evidence of publication bias or threshold effect. The pooled sensitivity and pooled specificity of the mfVEP amplitude for detection of visual field defects in all studies was 0.93 and 0.89, respectively. The positive and negative likelihood ratios of mfVEP amplitude were 6.56 and 0.08, respectively. The amplitude of mfVEP showed a good diagnostic precision in the prediction of visual field defects. Interocular mfVEP amplitude analysis can be a good diagnostic indicator for visual field study.

Clinical electrophysiology of the optic nerve and retinal ganglion cells

Clinical electrophysiological assessment of optic nerve and retinal ganglion cell function can be performed using the Pattern Electroretinogram (PERG), Visual Evoked Potential (VEP) and the Photopic Negative Response (PhNR) amongst other more specialised techniques. In this review, we describe these electrophysiological techniques and their application in diseases affecting the optic nerve and retinal ganglion cells with the exception of glaucoma. The disease groups discussed include hereditary, compressive, toxic/nutritional, traumatic, vascular, inflammatory and intracranial causes for optic nerve or retinal ganglion cell dysfunction. The benefits of objective, electrophysiological measurement of the retinal ganglion cells and optic nerve are discussed, as are their applications in clinical diagnosis of disease, determining prognosis, monitoring progression and response to novel therapies.

Visual Evoked Potentials as a Biomarker in Multiple Sclerosis and Associated Optic Neuritis

: ABSTRACT:: Multiple sclerosis (MS) is an inflammatory, degenerative disease of the central nervous system (CNS) characterized by progressive neurological decline over time. The need for better "biomarkers" to more precisely capture and track the effects of demyelination, remyelination, and associated neuroaxonal injury is a well-recognized challenge in the field of MS. To this end, visual evoked potentials (VEPs) have a role in assessing the extent of demyelination along the optic nerve, as a functionally eloquent CNS region. Moreover, VEPs testing can be used to predict the extent of recovery after optic neuritis (ON) and capture disabling effects of clinical and subclinical demyelination events in the afferent visual pathway. In this review, the evolving role of VEPs in the diagnosis of patients with ON and MS and the utility of VEPs testing in determining therapeutic benefits of emerging MS treatments is discussed.

Fingolimod after a first unilateral episode of acute optic neuritis (MOVING) - preliminary results from a randomized, rater-blind, active-controlled, phase 2 trial

Background

Neuroprotection and promotion of remyelination represent important therapeutic gaps in multiple sclerosis (MS). Acute optic neuritis (ON) is a frequent MS manifestation. Based on the presence and properties of sphingosine-1-phosphate receptors (S1PR) on astrocytes and oligodendrocytes, we hypothesized that remyelination can be enhanced by treatment with fingolimod, a S1PR modulator currently licensed for relapsing-remitting MS.

Methods

MOVING was an investigator-driven, rater-blind, randomized clinical trial. Patients with acute unilateral ON, occurring as a clinically isolated syndrome or MS relapse, were randomized to 6 months of treatment with 0.5 mg oral fingolimod or subcutaneous IFN-β 1b 250 μg every other day. The change in multifocal visual evoked potential (mfVEP) latency of the qualifying eye was examined as the primary (month 6 vs. baseline) and secondary (months 3, 6 and 12 vs. baseline) outcome. In addition, full field visual evoked potentials, visual acuity, optical coherence tomography as well as clinical relapses and measures of disability, cerebral MRI, and self-reported visual quality of life were obtained for follow-up. The study was halted due to insufficient recruitment (n = 15), and available results are reported.

Results

Per protocol analysis of the primary endpoint revealed a significantly larger reduction of mfVEP latency at 6 months compared to baseline with fingolimod treatment (n = 5; median decrease, 15.7 ms) than with IFN-β 1b treatment (n = 4; median increase, 8.15 ms) (p <  0.001 for interaction). Statistical significance was maintained in the secondary endpoint analysis. Descriptive results are reported for other endpoints.

Conclusion

Preliminary results of the MOVING trial argue in support of a beneficial effect of fingolimod on optic nerve remyelination when compared to IFN-β treatment. Interpretation is limited by the small number of complete observations, an unexpected deterioration of the control group and a difference in baseline mfVEP latencies. The findings need to be confirmed in larger studies.

Trial registration

The trial was registered as EUDRA-CT 2011–004787-30 on October 26, 2012 and as NCT01647880 on July 24, 2012.

Longitudinal optic neuritis-unrelated visual evoked potential changes in NMO spectrum disorders

OBJECTIVE

To investigate if patients with neuromyelitis optica spectrum disorder (NMOSD) develop subclinical visual pathway impairment independent of acute attacks.

METHODS

A total of 548 longitudinally assessed full-field visual evoked potentials (VEP) of 167 patients with NMOSD from 16 centers were retrospectively evaluated for changes of P100 latencies and P100-N140 amplitudes. Rates of change in latencies (RCL) and amplitudes (RCA) over time were analyzed for each individual eye using linear regression and compared using generalized estimating equation models.

RESULTS

The rates of change in the absence of optic neuritis (ON) for minimal VEP intervals of ≥3 months between baseline and last follow-up were +1.951 ms/y (n = 101 eyes; SD = 6.274; p = 0.012) for the P100 latencies and -2.149 µV/y (n = 64 eyes; SD = 5.013; p = 0.005) for the P100-N140 amplitudes. For minimal VEP intervals of ≥12 months, the RCL was +1.768 ms/y (n = 59 eyes; SD = 4.558; p = 0.024) and the RCA was -0.527 µV/y (n = 44 eyes; SD = 2.123; p = 0.111). The history of a previous ON >6 months before baseline VEP had no influence on RCL and RCA. ONs during the observational period led to mean RCL and RCA of +11.689 ms/y (n = 16 eyes; SD = 17.593; p = 0.003) and -1.238 µV/y (n = 11 eyes; SD = 3.708; p = 0.308), respectively.

CONCLUSION

This first longitudinal VEP study of patients with NMOSD provides evidence of progressive VEP latency delay occurring independently of acute ON. Prospective longitudinal studies are needed to corroborate these findings and help to interpret the clinical relevance.

Sensitive Assessment of Acute Optic Neuritis by a New, Digital Flicker Test

BACKGROUND

The Aulhorn flicker test (AFT) previously showed promise in diagnosing acute optic neuritis (ON) albeit with suboptimal sensitivity. A new, digitalized version of the AFT (the DFT) has not previously been examined in acute ON.

OBJECTIVES

To examine the sensitivity, specificity and reproducibility of the DFT in acute ON.

METHOD

The DFT assesses the subjective brightness of a flickering field (1-60 Hz). In normal subjects, brightness enhancement occurs at intermediate frequencies, whereas in acute ON darkness enhancement (DE) is hypothesized. AFT and DFT measurements were obtained in acute ON patients (≤31 days from first symptom) with DE as a quantitative covariate. Reproducibility of the DFT end point was assessed in the form of an intraclass correlation.

RESULTS

30 untreated first-time acute ON patients and 55 healthy controls were examined. AFT and DFT were performed 12.7 days (range: 4-30) following ON onset. The DFT showed a sensitivity of 0.93 (95% CI = 0.78-0.99) to a specificity of 0.96 (95% CI = 0.87-1.00). The AFT showed a sensitivity of 0.76 (95% CI = 0.56-0.90) to a specificity of 1.00 (95% CI = 0.93-1.00). No significant correlation was shown between DFT and visual acuity. The intraclass correlation of the DFT end point in healthy subjects was 0.84.

CONCLUSIONS

We present a new DFT in acute ON displaying a high specificity of 0.96 and a sensitivity of 0.93. Our study indicates the DFT to be an accurate and easy-to-use tool in diagnosing acute ON, which may be especially helpful in atypical cases.

Optical coherence tomography and multiple sclerosis: Update on clinical application and role in clinical trials

Optical coherence tomography (OCT) has emerged as a fast, non-invasive, inexpensive, high-resolution imaging technique in multiple sclerosis (MS). Retinal layer quantification by OCT facilitates a 'window' into not only local retinal pathology but also global neurodegenerative processes, recognised to be the principal substrates of disability accumulation in MS. While OCT measures in MS have been demonstrated to reflect visual function, inflammatory activity outside of the visual pathways, disability measures including the prediction of disability progression, whole brain atrophy, and the differential neuroprotective effects of disease-modifying therapies, debate continues regarding the clinical utility of OCT in everyday practice. This review presents an overview of the evidence supporting OCT, with particular focus on its application in the MS clinic. We will also discuss the role of OCT in MS clinical trials to develop novel neuroprotective and potential remyelinating therapies.

The electrophysiological assessment of visual function in Multiple Sclerosis

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VEPs have largely been replaced by MRI in modern MS diagnosis and management.

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Multifocal VEPs are superior to traditional VEPs in evaluating the integrity of the visual system.

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Physiological asymmetry limits interpretation of small VEP differences.

The assessment of vision is integral to the diagnosis and monitoring of patients with multiple sclerosis (MS). Visual electrophysiology, previously a critical investigation in patients with suspected MS, has in large part been supplanted by magnetic resonance imaging in clinical routine. However, the development of multi-focal visual evoked potentials and the advent of putative re-myelinating therapies that can be monitored with these techniques has led to a resurgence of interest in the field. Here, we review the clinical applications, technical considerations and limitations of visual evoked potentials in the management of patients with MS.

Optical Coherence Tomography versus Visual Evoked Potentials for Detecting Visual Pathway Abnormalities in Patients with Neuromyelitis Optica Spectrum Disorder

Background and Purpose

Optical coherence tomography (OCT) and visual evoked potentials (VEPs) can be used to detect optic neuritis (ON). However, the comparative sensitivities of OCT and VEPs for detecting ON in neuromyelitis optica spectrum disorder (NMOSD) are unclear, and so we assessed these sensitivities.

Methods

This cross-sectional study included 73 patients with aquaporin-4 antibody-seropositive NMOSD, and 101 eyes with ON. The clinical characteristics, visual acuity (VA), Expanded Disability Status Scale (EDSS) scores, OCT peripapillary retinal nerve fiber layer (RNFL) thickness, and VEPs of the patients were evaluated.

Results

OCT and VEPs were abnormal in 68% and 73% of eyes with a history of ON, respectively, and in 2% and 9% of eyes without ON. Test sensitivities were influenced by the number of ON episodes: the OCT RNFL thickness and VEPs were abnormal in 50% and 67% of the eyes with first-ever ON episode, respectively (p=0.041), with the combination of both tests detecting abnormalities in up to 75% of the eyes. The sensitivities of the OCT RNFL thickness and VEPs increased to 95% and 83%, respectively, after the second or subsequent ON episode (p=0.06), with the combination of both tests detecting abnormalities in 95% of cases. The OCT RNFL thickness and VEP latency/amplitude were correlated with EDSS scores and VA.

Conclusions

VEPs were superior for detecting subclinical or first-ever ON, while OCT was better for detecting eyes with multiple ON episodes. The correlations of OCT and VEPs with clinical disability measures indicate that these tests are potential markers of the disease burden in NMOSD.

Safety and efficacy of opicinumab in acute optic neuritis (RENEW): a randomised, placebo-controlled, phase 2 trial

BACKGROUND

The human monoclonal antibody opicinumab (BIIB033, anti-LINGO-1) has shown remyelinating activity in preclinical studies. We therefore assessed the safety and tolerability, and efficacy of opicinumab given soon after a first acute optic neuritis episode.

METHODS

This randomised, double-blind, placebo-controlled, phase 2 study (RENEW) was done at 33 sites in Australia, Canada, and Europe in participants (aged 18-55 years) with a first unilateral acute optic neuritis episode within 28 days from study baseline. After treatment with high-dose methylprednisolone (1 g/day, intravenously, for 3-5 days), participants were assigned with a computer-generated sequence with permuted block randomisation (1:1) using a centralised interactive voice and web response system to receive 100 mg/kg opicinumab intravenously or placebo once every 4 weeks (six doses) and followed up to week 32. All study participants and all study staff, including the central readers, were masked to treatment assignment apart from the pharmacist responsible for preparing the study treatments and the pharmacy monitor at each site. The primary endpoint was remyelination at 24 weeks, measured as recovery of affected optic nerve conduction latency using full-field visual evoked potential (FF-VEP) versus the unaffected fellow eye at baseline. Analysis was by intention-to-treat (ITT); prespecified per-protocol (PP) analyses were also done. This study is registered with ClinicalTrials.gov, number NCT01721161.

FINDINGS

The study was done between Dec 21, 2012, and Oct 21, 2014. 82 participants were enrolled, and 41 in each group comprised the ITT population; 33 participants received opicinumab and 36 received placebo in the PP population. Adjusted mean treatment difference of opicinumab versus placebo was -3·5 ms (17·3 vs 20·8 [95% CI -10·6 to 3·7]; 17%; p=0·33) in the ITT population, and -7·6 ms in the PP population (14·7 vs 22·2 [-15·1 to 0·0]; 34%; p=0·050) at week 24 and -6·1 ms (15·1 vs 21·2 [-12·7 to 0·5]; 29%; p=0·071) in the ITT population and -9·1 ms (13·2 vs 22·4 [-16·1 to -2·1]; 41%; p=0·011) in the PP population at week 32. The overall incidence (34 [83%] of 41 in each group) and severity of adverse events (two [5%] of 41 severe adverse events with placebo vs three [7%] of 41 with opicinumab) were similar between groups and no significant effects on brain MRI measures were noted in either group (mean T2 lesion volume change, 0·05 mL [SD 0·21] for placebo vs 0·20 mL [0·52] with opicinumab; 27 [77%] of 35 participants with no change in gadolinium-enhancing [Gd+] lesion number with opicinumab vs 27 [79%] of 34 with placebo; mean 0·4 [SD 0·79 for the placebo group and 0·85 for the opicinumab group] new Gd+ lesions per participant in both groups). Treatment-related serious adverse events were reported in three (7%) of 41 participants in the opicinumab group (hypersensitivity [n=2], asymptomatic increase in transaminase concentrations [n=1]) and none of the participants in the placebo group.

INTERPRETATION

Remyelination did not differ significantly between the opicinumab and placebo groups in the ITT population at week 24. However, results from the prespecified PP population suggest that enhancing remyelination in the human CNS with opicinumab might be possible and warrant further clinical investigation.

FUNDING

Biogen.

Baseline magnetic resonance imaging of the optic nerve provides limited predictive information on short-term recovery after acute optic neuritis

Background

In acute optic neuritis, magnetic resonance imaging (MRI) may help to confirm the diagnosis as well as to exclude alternative diagnoses. Yet, little is known on the value of optic nerve imaging for predicting clinical symptoms or therapeutic outcome.

Purpose

To evaluate the benefit of optic nerve MRI for predicting response to appropriate therapy and recovery of visual acuity.

Methods

Clinical data as well as visual evoked potentials (VEP) and MRI results of 104 patients, who were treated at the Department of Neurology with clinically definite optic neuritis between December 2010 and September 2012 were retrospectively reviewed including a follow up within 14 days.

Results

Both length of the Gd enhancing lesion (r = -0.38; p = 0.001) and the T2 lesion (r = -0.25; p = 0.03) of the optic nerve in acute optic neuritis showed a medium correlation with visual acuity after treatment. Although visual acuity pre-treatment was little but nonsignificantly lower if Gd enhancement of the optic nerve was detected via orbital MRI, improvement of visual acuity after adequate therapy was significantly better (0.40 vs. 0.24; p = 0.04). Intraorbitally located Gd enhancing lesions were associated with worse visual improvement compared to canalicular, intracranial and chiasmal lesions (0.35 vs. 0.54; p = 0.02).

Conclusion

Orbital MRI is a broadly available, valuable tool for predicting the improvement of visual function. While the accurate individual prediction of long-term outcomes after appropriate therapy still remains difficult, lesion length of Gd enhancement and T2 lesion contribute to its prediction and a better short-term visual outcome may be associated with detection and localization of Gd enhancement along the optic nerve.

Multifocal VEP assessment of optic neuritis evolution

OBJECTIVE

To evaluate multifocal visual evoked potentials (mfVEP) changes in optic neuritis (ON) and fellow eyes during first year after the attack.

METHODS

Eighty-seven patients and twenty-five controls were examined. Patients were classified as multiple sclerosis (MS) group, high risk (HR) or low risk (LR) groups for conversion to MS. mfVEP recordings and retinal nerve fiber layer (RNFL) thickness were analyzed.

RESULTS

Recovery of amplitude and shortening of latency was fastest within the first 3months. The largest amplitude reduction and longest latency delay of the ON eye were recorded in the MS group. This was accompanied by deterioration of both parameters in fellow eyes (p<0.03). mfVEP remained stable in fellow eyes of the LR group. Inter-eye asymmetry showed similar amount of amplitude reduction and latency delay in all three groups. RNFL thickness strongly correlated with mfVEP amplitude as early as 3 months after ON (R(2)=0.6, p=0.001).

CONCLUSION

mfVEP amplitude is an early predictor of post-ON axonal loss. The apparent more severe involvement of ON eyes in the MS subgroup may be due to subclinical inflammation along the visual pathway.

SIGNIFICANCE

Severity of amplitude reduction and latency delay after episode of ON is not MS-related. Retro-chiasmal demyelination is a possible factor contributing to amplitude and latency differences between MS and non-MS patients.

The value of clinical electrophysiology in the assessment of the eye and visual system in the era of advanced imaging

Electrophysiological techniques allow clinical investigations to include a 'dissection' of the visual system. Using suitable electrophysiological techniques, the 'dissection' allows function to be ascribed to the different photoreceptors (rod and cone photoreceptors), retinal layers, retinal location or the visual pathway up to the visual cortex. Combined with advances in genetics, retinal biochemistry, visual fields and ocular imaging, it is now possible to obtain a better understanding of diseases affecting the retina and visual pathways. This paper reviews core electrophysiological principles that can complement other examination techniques, including advanced ocular imaging, and help the interpretation of other clinical data and thus, refine and guide clinical diagnosis.

Clinical neurophysiology of multiple sclerosis

The availability of new treatments able to modify the natural course of multiple sclerosis (MS) has generated interest in paraclinical measures to monitor disease evolution. Among these, neurophysiologic measures, mainly evoked potentials (EPs), are used in the functional assessment of central sensorimotor and cognitive networks affected by MS. EP abnormalities may reveal subclinical lesions, objectivate the involvement of sensory and motor pathways in the presence of vague disturbances, and provide indications of the demyelinating nature of the disease process. However, their diagnostic value is much lower than that of magnetic resonance imaging, and is more sensitive to brain and cervical spinal cord lesions. The application of EPs in assessing disease severity and monitoring the evolution of nervous damage is more promising, thanks to their good correlation with disability in cross-sectional and longitudinal studies, and potential use as paraclinical endpoints in clinical trials. Recent evidence indicates that EPs performed early in the disease may help to predict a worse future progression in the long term. If confirmed, these data suggest the possible usefulness of EPs in the early identification of patients who are more likely to develop future disability, thus requiring more frequent monitoring or being potential candidates for more aggressive disease-modifying treatments.

Simvastatin improves final visual outcome in acute optic neuritis: a randomized study

Background: In recent years, small-scale clinical trials have indicated that statins or 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors exert pleiotropic immunomodulatory effects, with potential therapeutic implications in multiple sclerosis (MS).

Objective: To investigate whether simvastatin treatment (80 mg daily for 6 months) in patients with optic neuritis (ON) had a beneficial effect on visual outcome and on brain MRI.

Methods: Sixty-four patients with acute ON were randomized to simvastatin treatment ( n = 32) or placebo ( n = 32) for 6 months. None of the patients had been on immunosuppressive therapy for 6 months prior to inclusion or treated with steroids from symptom onset. Contrast sensitivity (Arden plates), visual acuity, colour perception, visual evoked potentials (VEP) – latency and amplitude, Visual Analogue Scale (VAS) score, and gadolinium enhancing and T2 lesions on brain MRI were evaluated at screening visit, day 14 (except brain MRI), day 90 and day 180.

Results: Simvastatin had a beneficial effect on VEP in both latency ( p = 0.01) and amplitude ( p = 0.01), a borderline effect on the Arden score ( p = 0.06) and VAS ( p = 0.04), and no effect on brain MRI or on relapse rate between the groups.

Conclusion: This study provides Class I evidence that simvastatin 80 mg daily is well tolerated and possibly effective in patients with acute ON.

Eye disorders in patients with multiple sclerosis: natural history and management

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system and leading cause of disability in young adults. Vision impairment is a common component of disability for this population of patients. Injury to the optic nerve, brainstem, and cerebellum leads to characteristic syndromes affecting both the afferent and efferent visual pathways. The objective of this review is to summarize the spectrum of eye disorders in patients with MS, their natural history, and current strategies for diagnosis and management. We emphasize the most common disorders including optic neuritis and internuclear ophthalmoparesis and include new techniques, such as optical coherence tomography, which promise to better our understanding of MS and its effects on the visual system.

Assessing visual pathway function in multiple sclerosis patients with multifocal visual evoked potentials

Multifocal visual evoked potentials provide a topographic measure of visual response amplitude and latency. The objective of this study was to evaluate the sensitivity and specificity of the multifocal visual evoked potential technique in detecting visual abnormalities in patients with multiple sclerosis. Multifocal visual evoked potentials were recorded from 74 patients with multiple sclerosis with history of optic neuritis (MS-ON, n = 74 eyes) or without (MS-no-ON, n = 71 eyes), and 50 normal subjects (controls, n = 100 eyes) using a 60-sector pattern reversal dartboard stimulus (VERIS). Amplitude and latency for each sector were compared with normative data and assigned probabilities. Size and location of clusters of adjacent abnormal sectors (p < 0.05) were examined. Mean response amplitudes were (+/- SE) 0.39 +/- 0.02, 0.53 +/- 0.02, and 0.60 +/- 0.01 for MS-ON, MS-no-ON, and control groups, respectively, with significant differences between all groups (p < 0.0001). Mean latencies (ms; +/-SE relative to normative data) were 12.7 +/- 1.3 (MS-ON), 4.3 +/- 1.1 (MS-no-ON), and 0.3 +/- 0.4 (controls); group differences again significant (p < 0.0001). Half the MS-ON eyes had clusters larger than five sectors compared with 13% in MS-no-ON and 2% in controls. Abnormal sectors were distributed diffusely, although the largest cluster was smaller than 15 sectors in two-thirds of MS-ON eyes. Cluster criteria combining amplitude and latency showed an area of 0.96 under the receiver operating characteristic curve, yielding a criterion with 91% sensitivity and 95% specificity. We conclude that the multifocal visual evoked potential provides high sensitivity and specificity in detecting abnormalities in visual function in multiple sclerosis patients.

Optical coherence tomography is less sensitive than visual evoked potentials in optic neuritis

OBJECTIVES

Determine the utility of optical coherence tomography (OCT) to detect clinical and subclinical remote optic neuritis (ON), its relationship to clinical characteristics of ON and visual function, and whether the retinal nerve fiber layer (RNFL) thickness functions as a surrogate marker of global disease severity.

METHODS

Cross-sectional study of 65 subjects with at least 1 clinical ON episode at least 6 months prior. Measures included clinical characteristics, visual acuity (VA), contrast sensitivity (CS), OCT, and visual evoked potentials (VEP).

RESULTS

Ninety-six clinically affected optic nerves were studied. The sensitivity of OCT RNFL after ON was 60%, decreasing further with mild onset and good recovery. VEP sensitivity was superior at 81% (p = 0.002). Subclinical ON in the unaffected eye was present in 32%. VEP identified 75% of all subclinically affected eyes, and OCT identified <20%. RNFL thickness demonstrated linear correlations with VA (r = 0.65) and CS (r = 0.72) but was unable to distinguish visual categories <20/50. RNFL was thinner with severe onset and disease recurrence but was unaffected by IV glucocorticoids. OCT measurements were not related to overall disability, ethnicity, sex, or age at onset. The greatest predictor for RNFL in the unaffected eye was the RNFL in the fellow affected eye.

CONCLUSIONS

Visual evoked potentials (VEP) remains the preferred test for detecting clinical and subclinical optic neuritis. Optical coherence tomography (OCT) measures were unrelated to disability and demographic features predicting a worse prognosis in multiple sclerosis. OCT may provide complementary information to VEP in select cases, and remains a valuable research tool for studying optic nerve disease in populations.

Outcome measures for trials of remyelinating agents in multiple sclerosis: retrospective longitudinal analysis of visual evoked potential latency

Objective

Visual evoked potentials (VEP) may be suitable surrogate outcome measures in multiple sclerosis (MS) remyelination trials. The extent of spontaneous changes of subclinically delayed VEP is unknown, whereas VEP improve after acute optic neuritis (ON).

Methods

In all, 124 patients with three VEP recordings at least 3 months apart: 71 patients with MS who had never suffered clinical ON; 53 patients with ON (isolated ON or ON as an attack of MS at first recording). Latencies of P100 were analyzed by multivariate analysis of variance.

Results

Eyes of patients with MS had a mean P100 latency of 110.2 ms, worsening mildly over time ( n = 104 eyes, P = 0.022). MS patients' eyes with subclinical demyelination (delayed P100 latency at first recording >116 ms) showed no significant evidence of remyelination ( n = 24 eyes, P = 0.27). By contrast, in ON patients' affected eyes, mean P100 latency decreased ( P = 0.001), whereas unaffected eyes remained stable ( P = 0.26). Clinically non-affected eyes from both diagnostic groups with subclinically prolonged latencies remained stable ( n = 32: mean P100 at 124.8 ± 10.7, 123.5 ± 13.6, and 122.8 ± 13.1 ms; P = 0.57), whereas non-affected eyes with normal latency at baseline deteriorated slightly ( P = 0.001). A subgroup with more homogeneously defined follow-up periods confirmed this observation. Non-affected eyes selected for stability (difference <5 ms) between first and second recording deteriorated (normal baseline, n = 66 eyes, P = 0.013) or remained stable (prolonged baseline, n = 18 eyes, 95% confidence interval of change –5.42 to +6.89 ms, P = 0.805).

Conclusion

Prolonged P100 latencies in eyes never affected by clinical ON remain stable and thus can be used as surrogate outcome measure for remyelination trials.

Neurophysiological markers

After the advent of immunomodulatory treatment in Multiple Sclerosis and after several options for early treatment have become available, the early identification of patients non responder has become a very important issue. Therefore, methods are needed for the detection of disease activity and, particularly in more advanced phases of the disease, of disease progression. Neurophysiological methods, mainly evoked potentials (EPs), are widely used in the functional assessment of sensory and motor pathways. Their usefulness in the assessment of disease activity is limited by the fact that, although they can also reveal clinically silent lesions, EPs abnormalities are present only if their corresponding pathway is involved. With this respect, EPs have been extensively replaced by magnetic resonance imaging (MRI), with the exception of optic nerve in which the sensitivity of EPs and MRI is similar. Nevertheless, EPs can be useful for the assessment of disease progression, since their abnormalities have been demonstrated to be more strictly related to disability than MRI lesion burden. With this perspective, EPs can still be useful in the identification of non responder by providing the clinician with objective functional assessment of eloquent pathways in patients with ambiguous new symptoms, for the confirmation of a dubious relapse, and by providing a method for detecting worsening of nervous conduction for the confirmation of disease progression.

[Adaptive estimation of contrast thresholds using the visual evoked potential (VEP)]

The visual evoked potential (VEP) can be used to objectively estimate sensory thresholds. Recently, we developed an adaptive procedure for this threshold estimation based on a Fourier analysis of steady-state responses during the recording. In this study we quantified the reduction in recording time of this adaptive procedure. Steady-state VEPs to pattern reversal (f = 8.3 Hz) of checkerboards with 8 contrast values between 0.64% and 82% were recorded monocularly. Adaptive and non-adaptive recordings were performed for full correction (fc) and for blurred stimulus patterns (+1.5 D and +3.0D). VEP contrast thresholds were defined by the lowest contrast condition that showed a significant response. An ANOVA of the VEP thresholds showed significant effects (p < 0.0001) of the factors "procedure" (psychophysics, adaptive VEP, non-adaptive VEP) and "correction" (fc, fc + 1.5D, fc + 3.0D). Compared to non-adaptive recordings, adaptive recordings showed thresholds that were significantly reduced and closer to psychophysical contrast thresholds. By applying the adaptive procedure the recording time can be reduced by a factor of about 2 when compared to the non-adaptive procedure. The new adaptive VEP procedure may help to improve the correlation of electrophysiological and psychophysical estimates of sensory thresholds and may accelerate functional testing in the clinical routine.

Optical coherence tomography versus automated perimetry for follow-up of optic neuritis

PURPOSE

To evaluate the usefulness of optical coherence tomography (OCT) for follow-up of optic neuritis (ON) compared with subjective visual function tests.

METHODS

Twelve patients with ON underwent a complete ophthalmological evaluation at initial diagnosis, including best corrected visual acuity (VA), visual fields testing and OCT examination. These examinations were repeated periodically over 6 months. Retinal nerve fibre layer (RNFL) thickness evolution was analysed and correlated with VA and visual field mean deviation.

RESULTS

Six months after ON, mean RNFL in the affected eye decreased significantly compared with that in the fellow eye (24.54%). A significant correlation was found between RNFL thinning and final VA (r = 0.807, p = 0.005), with a 1-line drop in VA for every 5.4-micro m decrease. All patients with an altered visual field had an abnormal RNFL value; of the seven patients with normal visual fields, 57% had an abnormal RNFL value (p < 5%).

CONCLUSIONS

Optical coherence tomography can detect axonal damage as early as the third month after an isolated initial episode of ON, even in the presence of normal visual fields. Mean RNFL thinning is correlated with final VA.

Contrast sensitivity, first-order motion and Initial ocular following in demyelinating optic neuropathy

The ocular following response (OFR) is a measure of motion vision elicited at ultra-short latencies by sudden movement of a large visual stimulus. We compared the OFR to vertical sinusoidal gratings (spatial frequency 0.153 cycles/ degrees or 0.458 cycles/ degrees) of each eye in a subject with evidence of left optic nerve demyelination due to multiple sclerosis (MS). The subject showed substantial differences in vision measured with stationary low-contrast Sloan letters (20/63 OD and 20/200 OS at 2.5% contrast) and the Lanthony Desaturated 15-hue color test (Color Confusion Index 1.11 OD and 2.14 OS). Compared with controls, all of the subject's OFR to increasing contrast showed a higher threshold. The OFR of each of the subject's eyes were similar for the 0.153 cycles/ degrees stimulus, and psychophysical measurements of his ability to detect these moving gratings were also similar for each eye. However, with the 0.458 cycles/ degrees stimulus, the subject's OFR was asymmetric and the affected eye showed decreased responses (smaller slope constant as estimated by the Naka-Rushton equation). These results suggest that, in this case, optic neuritis caused a selective deficit that affected parvocellular pathways mediating higher spatial frequencies, lower-contrast, and color vision, but spared the field-holding mechanism underlying the OFR to lower spatial frequencies. The OFR may provide a useful method to study motion vision in individuals with disorders affecting anterior visual pathways.

Low Conversion Rate to Multiple Sclerosis in Idiopathic Optic Neuritis Patients in Taiwan

PURPOSE

To investigate the clinical characteristics of patients with idiopathic optic neuritis (ON) in Taiwan and to assess the conversion rate to multiple sclerosis (MS) in these patients.

METHODS

We studied the medical records of a total of 109 patients with a clinical diagnosis of idiopathic ON treated in the Taipei Veterans General Hospital during the period from January 1986 to May 2003. Clinical characteristics, management, and disease courses were retrospectively reviewed. Our main focus was on the development of multiple sclerosis after an ON attack. Univariate and multivariate analyses were used to evaluate the risk indicators for MS conversion.

RESULTS

The patients (58 women, 51 men) had a mean age of 41.2 years at onset. ON was retrobulbar in 46.8% of the patients. Management with or without pulse therapy did not affect the final visual outcome. Female sex, retrobulbar type ON, recurrent cases, elevated cerebrospinal fluid (CSF) IgG index, and central nervous system (CNS) imaging abnormalities were identified as risk indicators for the development of MS (P < 0.05). The 2-year cumulative probability of developing MS was 5.92%, and the 5-year cumulative probability was 14.28%. The conversion rate to MS did not differ among treatment groups.

CONCLUSIONS

Idiopathic ON patients in Taiwan have an older age at onset and a higher percentage of optic disc edema than reported in previous literature. The characteristic features of ON patients associated with a high risk of developing MS are female sex, retrobulbar type ON, CNS imaging abnormalities, elevated CSF IgG index, and recurrence. Idiopathic ON patients in Taiwan display a significantly lower conversion rate to MS.

Automatic Discrimination of Abnormal Subjects Using the Visual Evoked Potential Spectral Components

Study of visual evoked potential (VEP) is one of the utilized methods in clinical diagnosis of ophthalmology and neurological disorders. The automatic detection of VEP spectral components is an important tool in the diagnosis of mental activity. This paper presents a novel computational approach using feedforward neural network to identify abnormal subjects from changes in spectral components. The output vector from the feedforward neural network is based on the VEP spectral components. The software was developed to identify mental state from the VEP spectral components using Matlab software package. Using this approach, it is possible to perform real-time abnormality identification accurately on personal computers.

The Multifocal Visual Evoked Potential

With the multifocal technique, visual evoked potentials (VEPs) can be recorded simultaneously from many regions of the visual field. For the multifocal VEP (mfVEP), the patient views a display that typically contains 60 sectors, each with a checkerboard pattern. The display covers about the same retinal area as the 24-2 Humphrey visual field (HVF). However, due to the scaling of the sectors of the mfVEP display, the fields are sampled differently by the mfVEP and HVF. To assess local defects in the visual field, the mfVEP responses must be compared with normal controls. These comparisons require relatively sophisticated analyses and software. Whereas the mfVEP can be recorded relatively easily with the same equipment used to record multifocal electroretinograms (mfERGs), the software needed to perform the analysis is not yet widely available. The mfVEP is valuable for ruling out non-organic visual loss, diagnosing and following patients with optic neuritis/multiple sclerosis, evaluating patients with unreliable or questionable HVFs, and following disease progression. When combined with the mfERG, diseases of the outer retina (before the retinal ganglion cells) can be distinguished from diseases of the ganglion cells and/or optic nerve. The difficulties encountered in recording and analyzing mfVEP responses are greater than those involved in full-field VEP testing. Thus, in its current form, the mfVEP is best recorded and interpreted by ophthalmologists and electrophysiologists experienced with the technique. However, this technique is developing rapidly; advances in commercial hardware and software are expected in the near future.

Normalisation of visual evoked potentials after optic neuritis

Normalisation of the visual evoked potential (VEP) in patients with optic neuritis (ON) appears to be a rare phenomenon. However, although several workers have indicated that it can happen, they have not followed up with subsequent VEP tests to confirm how long the VEP latency of the affected eye remains in the normal range. To resolve this, 18 patients with a clinical diagnosis of acute unilateral ON were followed for 5 years with repeated VEP tests to determine if the latency of the P2 wave from affected eye could return to the normal range. Furthermore, in cases where the latency returned to normal, the length of time that it remained so was also assessed. The normal range for the latency of the P2 wave was determined by measuring VEPs from a group of 18 healthy control subjects with a similar age distribution to the patients. This established an upper limit of 115.9 ms. At presentation the mean P2 latency of the affected eyes of the patients was 140 ms with a standard deviation of 16 ms. In general, the VEP latencies remained constant over the period of the investigation. However two patients demonstrated a return to normal latencies but this was only temporary. Their latencies become prolonged again within 2 years. These results provide evidence that the delayed P2 latency observed in patients with ON can return to the normal range in a small percentage of cases. However, this improvement may spontaneously deteriorateonce more as a result of further episodes of subacute demyelination.

Optic neuritis: clinical analysis of 27 cases

We retrospectively reviewed 27 cases diagnosed as idiopathic optic neuritis between 1992 and 2001 at Kaohsiung Veterans General Hospital to assess the clinical features, visual prognosis, neuroimaging, laboratory studies, and development of multiple sclerosis in Chinese patients with optic neuritis. Patient age ranged from 13 to 54 years (mean, 35.8 +/- 11.3 years). Five cases presented as bilateral optic neuritis and 22 as unilateral. Visual function improved gradually from 2 weeks after treatment. Twelve (44.4%) cases showed disc swelling and ocular pain was also noted in 44.4% of patients. All cases that underwent visual field and visual evoked potential tests showed abnormality in lesion eyes. Of the 23 cases that underwent neuroimaging studies, including computerized tomography (17 patients) and magnetic resonance imaging (6 patients), 10 revealed optic nerve thickening. Four cases (14.8%) developed multiple sclerosis during follow-up (mean, 4.3 years). The incidence of disc swelling was higher than that reported by the Optic Neuritis Treatment Trial, but the incidence of initial ocular pain, the presence of periventricular plaques, and the development of multiple sclerosis were lower in our study. The unilateral group had significantly better visual outcome than the bilateral group.

Neurophysiological evidence for long-term repair of MS lesions: implications for axon protection

After recovery from the acute stage of optic neuritis, a marked prolongation in the latencies of visual evoked potentials (VEPs) is typically observed. We have conducted three studies (one cross-sectional, two prospective), aimed at elucidating the progressive shortening of VEP latency, which frequently ensues over the following months or years. This has been shown to be a progressive process and a prevalent tendency in the patient population, proceeding for more than 2 years in spite of the fact that very little functional improvement in vision occurs after the first few months. We argue that the underlying process of repair is most likely to involve remyelination of demyelinated optic nerve axons. Rather than restoration of visual function (which may be virtually complete after as short a period as 3 months), the main importance of the long-term myelin repair process may consist in protecting demyelinated axons from subsequent, permanent degeneration. In the VEPs of the acutely unaffected fellow eyes followed up over 3 years, we observed an asymptomatic deterioration, possibly due to insidious processes of demyelination and/or axonal degeneration. Even in the relapsing/remitting stage of MS, therefore, there is electrophysiological evidence for involvement of clinically asymptomatic axons, which, in the later stages, may be manifested as progressive functional deterioration.

Functional magnetic resonance imaging in acute unilateral optic neuritis

Despite good clinical criteria for diagnosing optic neuritis (ON), only a few techniques can precisely assess its impact on visual brain function. The authors studied whether functional magnetic resonance imaging (fMRI) of visual activation reliably reflects the cerebral consequences of acute unilateral ON, and how fMRI correlates with clinical function and visual evoked potentials (VEPs). Twenty ON patients, before and after steroid treatment, were compared to 20 controls. Each eye was stimulated separately with a checkerboard pattern reversing at 1, 2, 4, and 8 Hz. VEPs were recorded the same day. Initially, affected eye responses differed significantly from those of unaffected counterparts and controls in 12 patients. Post hoc classification by fMRI criteria was correct in approximately 85%. fMRI and VEP response parameters (as well as visual acuity) correlated significantly. The higher stimulation frequencies yielded greater fMRI responses from unaffected eyes, but not from affected eyes, in controls. The fMRI responses were quantifiable in every subject, whereas in 11 ON eyes, no VEPs were obtained during the acute stage. The authors conclude that fMRI is sensitive to the cerebral response alteration during ON and might therefore contribute to evaluating the temporal evolution of the visual functional deficit during recovery or therapy.