Visual Evoked Response Latency Research Articles

Prospective study to evaluate incidence and indicators for early detection of ethambutol toxicity

AimsTo evaluate incidence of toxic optic neuropathy in patients receiving ethambutol (EMB) for 6 months and to identify its early indicators.MethodsWe included 50 patients on anti-tubercular therapy (ATT) including EMB...

Tracking evoked responses to auditory and visual stimuli in fetuses exposed to maternal high-risk conditions.

Magnetoencephalography (MEG) has been successfully applied to record fetal auditory (auditory evoked response [AER]) and visual evoked responses (VER). In this study, we report the AER and VER development trajectory by tracking the evoked response detectability and latency from recordings starting at 27weeks of gestation in pregnancies classified as high risk. Fetal MEG and ultrasound recordings were performed on 158 pregnant women, and the total number of fetal auditory and visual tests conducted was 321 and 237, respectively. The overall evoked response analysis showed 237 AER (73.8%) and 164 VER detections (69.2%). The mean AER latency was 290.7 (SD 125.5) ms and the mean VER latency was 293.7 (SD 114.5) ms. The rate of decrease (95% confidence limits) in average AER and VER first-peak latency between 100-350ms was 1.97 (-1.86, +5.81) ms/week and 1.35 (-3.83, +6.53) ms/week, respectively. This trend in high-risk fetuses conforms to the general trajectory of decrease in latency with gestational age progression, even though this decrease was non-significant, as reported in the case of normal growing fetuses. Although there was a significant difference in detection rates between male and female fetuses, this was not reflected in either latency values or the sensory modality applied. Furthermore, the main factors that had the most significant effect on response detectability included the presence of intervening layers of adipose tissue between the fetal head and stimulus source and an increase in the maternal body mass index.

Visual-Evoked-Response-Supported Outcome of Intravitreal Erythropoietin in Management of Indirect Traumatic Optic Neuropathy.

Purpose Investigating the efficacy of intravitreal injection of erythropoietin (EPO) in managing indirect traumatic optic neuropathy (ITON) of different durations. Methods A case series that included two groups of ITON patients: recent ITON group (<3 months trauma duration; 7 eyes) and old duration ITON group (3–36 months; 7 eyes). Diagnostic computerized tomography (CT) and baseline flash visual evoked response (VER) were performed at the presentation time. At the initial visit and each follow-up, all patients had undergone assessment of best-corrected visual acuity (BCVA), pupil reaction, and anterior and posterior segments. VER was repeated 1 and 3 months after injection. All patients received an intravitreal injection of 2000 IU EPO in 0.2 ml of commercially available sterile EPREX 4000 solution, Jansen Cilag, Zug, Switzerland. Five patients had received a second injection 3 months later. Results Significant improvement was found in BCVA, VER amplitude, and latency (P < 0.0001, 0.0154, and 0.0291, respectively). Initial values of BCVA, VER amplitude, and latency correlated significantly to the final values. Differences between recent and old trauma groups were insignificant in the three parameters. In patients who received second injection, further clinical but statistically insignificant improvement was noted in BCVA in 60% of patients, VER amplitude in 50% of patients, and in VER latency in 100% of patients. No complications were recorded. Conclusion Intravitreal injection of EPO may be effective and safe in treatment of recent and old indirect traumatic optic neuropathy.

Steroids versus No Steroids in Nonarteritic Anterior Ischemic Optic Neuropathy: A Randomized Controlled Trial

To examine the role of oral steroid therapy in the treatment of nondiabetic cases of acute nonarteritic anterior ischemic optic neuropathy (NAAION). Randomized double-blind clinical trial. Thirty-eight patients with acute nondiabetic NAAION divided into 2 arms of 19 patients each. One arm constituted the cases and the other constituted the controls. Cases received oral steroid therapy and were designated the steroid group, whereas controls received placebo and were designated the nonsteroid group. Best-corrected visual acuity (BCVA), visual evoked response (VER), and OCT were performed at baseline, 1 month, 3 months, and 6 months after recruitment into thetrial. Best-corrected visual acuity, VER, and retinal nerve fiber layer changes on OCT. Both groups showed significant improvement in BCVA, VER latency, and resolution of disc edema on OCT parameters over 6 months. Final outcome showed no statistically significant difference with regard to visual acuity, although VER was better in the steroid group (P= 0.011). Best-corrected visual acuity, VER amplitude, and VER latency (P= 0.02, P= 0.02, and P= 0.04, respectively) showed a greater percentage improvement in the steroid group, which also saw a faster resolution of disc edema on OCT (1-month follow-up). Oral steroids in acute NAAION did not improve the visual acuity significantly at 6 months. However, they improved resolution of disc edema significantly and enabled a greater improvement in VER parameters. This subtle benefit of oral steroids in NAAION is clinically unimportant and does not provide support for its use.

Autologous mesenchymal stem cells for the treatment of secondary progressive multiple sclerosis: an open-label phase 2a proof-of-concept study

SummaryBackgroundMore than half of patients with multiple sclerosis have progressive disease characterised by accumulating disability. The absence of treatments for progressive multiple sclerosis represents a major unmet clinical need. On the basis of evidence that mesenchymal stem cells have a beneficial effect in acute and chronic animal models of multiple sclerosis, we aimed to assess the safety and efficacy of these cells as a potential neuroprotective treatment for secondary progressive multiple sclerosis.MethodsPatients with secondary progressive multiple sclerosis involving the visual pathways (expanded disability status score 5·5–6·5) were recruited from the East Anglia and north London regions of the UK. Participants received intravenous infusion of autologous bone-marrow-derived mesenchymal stem cells in this open-label study. Our primary objective was to assess feasibility and safety; we compared adverse events from up to 20 months before treatment until up to 10 months after the infusion. As a secondary objective, we chose efficacy outcomes to assess the anterior visual pathway as a model of wider disease. Masked endpoint analyses was used for electrophysiological and selected imaging outcomes. We used piecewise linear mixed models to assess the change in gradients over time at the point of intervention. This trial is registered with ClinicalTrials.gov, number NCT00395200.FindingsWe isolated, expanded, characterised, and administered mesenchymal stem cells in ten patients. The mean dose was 1·6×106 cells per kg bodyweight (range 1·1–2·0). One patient developed a transient rash shortly after treatment; two patients had self-limiting bacterial infections 3–4 weeks after treatment. We did not identify any serious adverse events. We noted improvement after treatment in visual acuity (difference in monthly rates of change −0·02 logMAR units, 95% CI −0·03 to −0·01; p=0·003) and visual evoked response latency (−1·33 ms, −2·44 to −0·21; p=0·020), with an increase in optic nerve area (difference in monthly rates of change 0·13 mm2, 0·04 to 0·22; p=0·006). We did not identify any significant effects on colour vision, visual fields, macular volume, retinal nerve fibre layer thickness, or optic nerve magnetisation transfer ratio.InterpretationAutologous mesenchymal stem cells were safely given to patients with secondary progressive multiple sclerosis in our study. The evidence of structural, functional, and physiological improvement after treatment in some visual endpoints is suggestive of neuroprotection.FundingMedical Research Council, Multiple Sclerosis Society of Great Britain and Northern Ireland, Evelyn Trust, NHS National Institute for Health Research, Cambridge and UCLH Biomedical Research Centres, Wellcome Trust, Raymond and Beverly Sackler Foundation, and Sir David and Isobel Walker Trust.

Visual function alterations in orbital tumors and factors predicting visual outcome after surgery

To study the effect of orbital tumors on visual functions and highlight the factors predictive of visual outcome after surgery. A prospective interventional study compared visual function parameters and fundus changes, before and after surgery, in eyes having well-defined orbital tumors with the normal fellow eye. These included visual acuity (VA), refractive error, keratometry changes, color vision, Goldmann visual field (GVF), and visual evoked response (VER). In total 28 cases (age range 7-56 years), of which the majority of tumors were vascular (46%) and lacrimal (18%) in origin, had a mean VA of 0.54±0.33 in the affected eye, which improved postoperatively to 0.66±0.31 (P=0.002). The affected eye had a median refractive error of +0.00 DS (-2.00 to 5.13), which was significantly more hyperopic than the normal eye (median +0.00 DS; range -1.25 to +1.63 DS) and normalized postoperatively. Keratometry showed higher astigmatism in the involved eye (P=0.004). The fundus showed disc pallor, edema, and/or choroidal folds, of which disc edema resolved in all cases after surgery. In all, 40% of the affected eyes had a deficient color vision and this partially improved postoperatively (P=0.25). GVF had abnormalities in 10 cases, half of which normalized postoperatively (P=0.04). The VER of affected eyes had a mean amplitude of 8.91±4.59 μv and latency of 116.3±14.7 ms, with improvement after surgery (P=0.005 and 0.001, respectively). Orbital tumors adversely affected visual functions. The presenting acuity depended on disc changes, color vision abnormalities, and prolonged VER latency. The postoperative VA depended on VA at presentation, amount of proptosis, degree of hyperopia, and clinically significant VER abnormalities.

Prospective evaluation of visual function for early detection of ethambutol toxicity

Aim:The aim of the study was to evaluate various visual parameters for early detection of ethambutol toxicity.Method:This was a prospective study of 104 eyes of 52 patients being treated with...

Nerve conduction, visual evoked responses and electroretinography in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents

The study examines possible persisting effects on the peripheral nervous system and visual system in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. We compared neurophysiological function in 44 tunnel workers previously exposed during grouting operations (2–10 years post exposure), with 49 tunnel workers with no history of exposure to acrylamide. Nerve conduction velocities (NCV), distal delay, F-response and amplitude in median and ulnar nerves of the right arm, peroneal, sural and tibial nerves of the right leg, visual evoked response (VER) and electroretinography (ERG) were measured. VER and ERG were also performed in 24 subjects more recently exposed to acrylamide grout (16 months post exposure). Exposure to acrylamide containing grouts was assessed by questionnaires. A statistically significant reduction in the mean sensory NCV of the sural nerve (p=0.005), as well as a non-significant reduction of sural amplitude was found in the previously exposed group compared to the control group. VER latencies to the onset of the occipital potential (N75) were prolonged in both exposed groups compared to the control group (p<0.05). ERG 30 Hz flicker amplitude was reduced in the recently exposed group compared to the referents (p<0.05). The results indicate slight subclinical, but persistent toxic effects in the sural nerve and the visual system in tunnel workers exposed to N-methylolacrylamide and acrylamide during grouting operations.

Iron in the Brain

After completing this article, readers should be able to: 1. Describe the role of iron in proteins involved in neuronal and glial energy metabolism, myelin production, and monoamine neurotransmitter metabolism. 2. Indicate the neonates who are at risk for iron deficiency. 3. Explain how iron deficiency affects the biochemistry, structure, signaling molecules, and electrophysiology of the hippocampus. 4. Describe the primary causes of iron overload in the neonate. 5. Explain why the preterm infant is at particular risk for iron deficiency. This article is designed to acquaint readers with the role of iron in early brain development. Several important principles that govern the effects of nutrients on the immature brain are discussed, followed by an explanation of the roles of iron during development. Because the developing brain is sensitive to iron overload as well as iron deficiency, both are discussed in the context of human studies and in model systems. The first guiding principle of nutrient-brain interactions during development is the concept of timing, dose, and duration. (1) The positive or negative effects of any nutrient depend on which brain regions or processes are developing at the time that nutrient status is altered and the requirements of those regions for the nutrient during that time of development. Generally, the more rapidly an area is developing, the more vulnerable it is. Dependence on specific nutrients during phases of rapid proliferation or differentiation results in the second principle, a regionalization of brain effects during periods of nutrient deficiency. In the case of iron deficiency, certain brain areas that are dependent on iron for proper development are more vulnerable than areas that are less dependent on iron. Additionally, these same brain areas are likely to be more vulnerable at certain time points than at others. To exert a maximal effect on regional brain development, the timing of iron …

Timing in the visual hierarchy

Vision scientists assume a hierarchy of visual areas in which `earlier' or `lower' areas respond faster than `later' or `higher' ones. A recent physiological study by Schmolesky et al. provides an extensive analysis of neural response latencies and their variability[ 1 Schmolesky M.T et al. Signal timing across the macaque visual system. J. Neurophysiol. 1998; 79: 3272-3278 PubMed Google Scholar ]. They presented four anesthetized macaque monkeys with visual stimuli and recorded visual-evoked response latencies in nine different areas of the visual system. By including a wide range of visual areas tested under identical procedures, their method enables comparisons of timing between various areas. The data revealed a cascade of activity, beginning in the magnocellular (M), then parvocellular (P), layers of the lateral geniculate nucleus (LGN), followed by cortical area V1. Next, activation was observed concurrently in areas V3, MT, MST, and the frontal eye fields (FEF). The latest activation was observed in V2 and V4. Response latencies ranged between 33 ms in the magnocellular LGN to 104 ms in V4. Strikingly, regions that fall in the ventral or `P' stream showed much slower and more variable responses than those in the dorsal or `M' stream, suggesting that M-stream cells might modulate the responses of P-stream cells. This demonstrates that visual hierarchies can be examined using timing properties in addition to the more established methods of neural connectivity.

Treatment with ac pulsed electromagnetic fields normalizes the latency of the visual evoked response in a multiple sclerosis patient with optic atrophy

Visual evoked response (VER) studies have been utilized as supportive information for the diagnosis of multiple sclerosis (MS) and may be useful in objectively monitoring the effects of various therapeutic modalities. Delayed latency of the VER, which reflects slowed impulse transmission in the optic pathways, is the most characteristic abnormality associated with the disease. Brief transcranial applications of AC pulsed electromagnetic fields (EMFs) in the picotesla flux density are efficacious in the symptomatic treatment of MS and may also reestablish impulse transmission in the optic pathways. A 36 year old man developed an attack of right sided optic neuritis at the age of 30. On presentation he had blurring of vision with reduced acuity on the right and fundoscopic examination revealed pallor of the optic disc. A checkerboard pattern reversal VER showed a delayed latency to right eye stimulation (P100 = 132 ms; normal range: 95-115 ms). After he received two successive applications of AC pulsed EMFs of 7.5 picotesla flux density each of 20 minutes duration administered transcra-nially, there was a dramatic improvement in vision and the VER latency reverted to normal (P100 = 107 ms). The rapid improvement in vision coupled with the normalization of the VER latency despite the presence of optic atrophy, which reflects chronic demyelination of the optic nerve, cannot be explained on the basis of partial or full reformation of myelin. It is proposed that in MS synaptic neurotransmitter deficiency is associated with the visual impairment and delayed VER latency following optic neuritis and that the recovery of the VER latency by treatment with pulsed EMFs is related to enhancement of synaptic neurotransmitter functions in the retina and central optic pathways. Recovery of the VER latency in MS patients may have important implications with respect to the treatment of visual impairment and prevention of visual loss. Specifically, repeated pulsed applications of EMFs may maintain impulse transmission in the optic nerve and thus potentially sustain its viability.

Effect of dietary linoleic/alpha-linolenic acid ratio on growth and visual function of term infants

Objectives: To determine the effect of α-linolenic acid (ALA) intake (or the dietary linoleic acid [LA]/ALA ratio) on the growth and visual function of term infants. Study design: Normal term infants were assigned randomly and in masked fashion at birth to receive formulas with approximately 16% of total fatty acids as LA and 0.4%, 1.0%, 1.7%, or 3.2% of fatty acids as ALA (LA/ALA ratios of 44, 18.2, 9.7, and 4.8) for the first 4 months of life. The fatty acid pattern of plasma phospholipids was determined shortly after birth and at approximately 21, 60, and 120 days of age. Anthropometric data were obtained at the same times and also at approximately 240 days of age. Transient visual evoked responses (VERs) were measured at approximately 120 and 240 days of age. For comparisons, anthropometric and VER data also were obtained in infants who were exclusively breast-fed for the first 4 months of life. Results: Infants who received the formula with 3.2% ALA (LA/ALA ratio, 4.8) had higher plasma concentrations of phospholipid docosahexaenoic acid (DHA) but lower concentrations of arachidonic acid at 21, 60, and 120 days of age. Mean weight of this group at 120 days of age was 760 gm less ( p < 0.05) than the mean weight of the group that received the formula with 0.4% ALA (LA/ALA ratio, 44). Despite differences in plasma phospholipid DHA contents among groups, neither VER latency nor amplitude differed significantly among formula groups or between any formula group and age-matched, breast-fed infants. Conclusions: The highest versus the lowest ALA intake (or the lowest vs the highest LA/ALA ratio) resulted in higher plasma phospholipid DHA content from 21 to 120 days of age but was not associated with improved visual function as assessed by transient VER. Moreover, mean body weight of infants who received the highest versus lowest ALA intake was less at 120 days ( p < 0.05). These data suggest that the lower LA/ALA ratios currently recommended for infant formulas should not be adopted until the effect of such ratios on growth are evaluated more completely. (J Pediatr 1997;131:200-9)

Stable quantitative EEG difference in post-LSD visual disorder by split-half analysis: evidence for disinhibition

Hallucinogen persisting perceptual disorder (HPPD) may follow the ingestion of LSD or other hallucinogens in a subset of users. It is characterized by chronic, intermittent or constant visual hallucinations of many sorts persisting beyond the period of acute drug effects. We studied 44 LSD-induced HPPD subjects and 88 matched controls to search for spectral and evoked potential differences using quantitative EEG (gEEG). HPPD subjects demonstrated faster alpha frequency and shorter VER (visual evoked response) latency, consistent with prior animal and human data on response to acute LSD administration which suggest LSD-induced cortical disinhibition. AER (auditory evoked response) latency was prolonged consistent with a differential LSD effect upon visual and auditory systems. The exploratory T-statistic significance probability mapping (T-SPM) technique demonstrated HPPD-control differences mostly involving temporal and left parietal scalp regions, confirmed by a split-half analysis. Significant variables were all derived from the long latency flash VER and click AER. None were derived from spectral analyzed EEG data. Canonical correlation between SPM-derived measures and variables reflecting disease severity was highly significant. A between-group stepwise discriminant analysis based upon a full set of gEEG measures demonstrated 87% prospective classification success by jackknifing and 88% success in a separate split-half analysis.

The prognostic value of visual evoked response latency in the treatment of amblyopia caused by strabismus.

Visual evoked response alterations and especially P100 latency were studied in 60 patents with amblyopia caused by strabismus. Patients were divided in two groups according to the mode of fixation of the strabismic eye. Group A included patients with eccentric fixation, and group B, patients with central fixation of the strabismic eye. In all cases visual evoked responses were recorded before and after a 6-month period during which the patients had full-time occlusion of the sound eye. In cases with eccentric fixation of the strabismic eye, P100 latency was more abnormal than in cases with central fixation. In cases where latencies are clearly abnormal before treatment, the prognosis is poor and the results after occlusion of the sound eye are unstable. In contrast, in the cases with normal or nearly normal visual evoked response latencies, the prognosis is better, and these eyes show satisfactory improvement of visual acuity.

The light-flash-evoked response as a possible indicator of increased intracranial pressure in hydrocephalus

Surgical treatment of infantile hydrocephalus by shunt implantation may result in suboptimal intracranial pressure. Major neurological impairments and death are usually prevented by shunt treatment, but minor sequelae may persist or develop. The introduction of adjustable shunts has improved the possibilities of optimizing shunt function and minimizing the risk of such impairments. However, it is still impossible to determine the intracranial pressure without invasive measurements. Clinical findings and procedures such as computed tomography (CT) are not always enough to allow a conclusion as to whether a child's signs and symptoms are the result of suboptimal intracranial pressure (shunt dysfunction) or are of another etiology. With the aim of reducing the number of invasive pressure measurements and CT scans, we investigated the effect of increased intracranial pressure on the visual evoked response (VER). Binocular light flash stimuli of supramaximal intensity were used and VER recordings were performed from Oz and Cz. The VER results from a group of 31 infants and children with hydrocephalus and 2 children with pseudotumor cerebri were compared with responses from a control group of 35 healthy children. The results show that a subpotential, P' (P-prime), usually just preceding P1 (P100), had an increased latency ( > 96 ms) in all hydrocephalic children before surgery. The P' latency in this group was usually even above 110 ms. The latencies of other VER potentials were also increased but not as consistently as P'. After surgical intervention the VER latencies decreased and usually normalized. The P' latency in four children in the control group was just above the borderline latency, but was less than 110 ms.(ABSTRACT TRUNCATED AT 250 WORDS)

Decreased visual evoked cortical response latency associated with cerebral ischaemia in the gerbil.

The observation of Xu et al. concerning reduction in latency of the visual evoked responses (VER) following cortical cryogenic injury, prompted us to ascertain whether similar VER changes could be demonstrable after ischaemic brain injury, especially, since both conditions have in common involvement of neuroexcitatory mechanisms. In our study, the Mongolian gerbils, which were subjected to 10 min bilateral carotid occlusion ischaemia, revealed decreased latency of the VER, with the peak of latency reduction between 4 and 7 h. An almost immediate decrease in VER latency was observed when glutamate was directly applied to the pial surface of the brain. These observations indicate that the reduction of VER latency may be related to neuroexcitation induced by release of excitatory amino acids, the latter constituting a widespread phenomenon, concomitant with brain injuries of various aetiologies.

The cause of increased pupillary light reflex latencies in diabetic patients: the relationship between pupillary light reflex and visual evoked potential latencies

In 42 diabetic patients the relationship between the latency of the pupillary light reflex and the pattern reversal visual evoked potential (P100) was examined. Fifty-five percent of diabetic patients had pupillary light reflex latencies above the normal range. In 19% the visual evoked potentials were prolonged when compared to the normal range. Latencies of pupillary light reflexes and VEPs showed no correlation. There was a minimal correlation between the presence of retinopathy and prolongation of both the pupillary light reflex and the visual evoked response latency (kappa coefficients respectively: 0.31, P < 0.01 and 0.36, P < 0.02). The presence of an increased pupillary light reflex latency was positively correlated with a reduced respiratory sinus arrhythmia (kappa coefficient: 0.58, P < 0.0001). Increased VEP latencies showed no correlation with signs of cardiovascular autonomic neuropathy. We conclude that the afferent optic pathway can be affected in diabetic patients. However, prolongation of pupillary light reflex latency in diabetic patients is primarily due to an efferent pupillary defect and represents parasympathetic dysfunction.

Preliminary trial of 3,4‐diaminopyridine in patients with multiple sclerosis

Ten patients with multiple sclerosis (MS) were enrolled in a preliminary trial of the potassium channel blocker, 3,4-diaminopyridine, to evaluate drug toxicity and pharmacokinetics. The patients were treated with oral 3,4-diaminopyridine, first with increasing single doses up to 100 mg and then with divided dosage for up to 3 weeks. Paresthesias were reported by all patients and abdominal pain was dose limiting in 6 patients. 3,4-Diaminopyridine levels and half-life varied widely from patient to patient. Cerebrospinal fluid levels of 3,4-diaminopyridine were about 10% of those in serum. Neither seizures nor epileptiform changes on electroencephalographic examination occurred. Small reversible improvements in specific neurological deficits were seen on examination in all patients and reversible improvement in visual evoked response latencies were found in 2 patients. These results suggest that further study of 3,4-diaminopyridine in patients with MS is warranted.

Functional development of the visual system in normal and protein‐deprived rats. IX. Visual evoked response in young rats

Changes in latencies of the visual evoked response (VER) during early post-natal development were examined in protein-deprived (PD) rats. The evoked response to light-flash stimulation was recorded in the dorsal lateral geniculate nucleus (dLGN) and on the surface of the visual cortex. In control rats, latencies of the cortical VER decreased rapidly up to 20 days and slowly thereafter. In PD rats, the latencies of the cortical VER were increased by 10-15 ms at 17 days; the developmental decrease was delayed by approximately 3 days. After 20 days, PD rats also went into a phase with slow decrease of the latencies, and the onset latency of the cortical VER was still increased by some 10 ms at 26/27 days. At this age, PD rats showed an increase in the latencies of the VER in the dLGN which was of similar magnitude to that in the cortical VER, indicating that alterations were more marked in the peripheral parts of the visual system at this stage of development. The findings are in agreement with previous studies indicating that there is a delay of visual system development in PD rats before 20 days. A maturational event which turns rapid into slow development at approximately 20 days in both C and PD rats turns this delay into a distortion of development. The delays and distortions of visual system development may be one causative factor for the functional deficit present in the visual cortex of adult PD rats.

Visual function and pattern visual evoked response in optic neuritis.

The disparity between clinical visual function and pattern visual evoked response (VER) was studied in 53 patients who had suffered an attack of optic neuritis (ON) more than six months before. The visual functions tested included Snellen visual acuity, colour vision, visual field, and contrast sensitivity. The effect of pattern presentation, check size, and luminance was tested by recording VERs with several stimulus configurations. VER amplitudes were found to be associated with the outcome of all four clinical tests, independently of check size, luminance, or the presentation method used. On the other hand VER latencies were hardly ever related to the results of any of the four clinical visual tests. These findings support the idea that VER amplitude provides information about visual spatial perception, while VER latency is more related to the extent of demyelination.