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The aim of this neurophysiological study was to monitor changes in the visual and cognitive function of HIV-infected patients treated with combination antiretroviral therapy. Eleven adult Czech HIV+ patients, with a mean age of 35 years and CD4 cell count ≥ 230 × 106 cells/L of blood at the time of enrollment, underwent four to six examinations over the course of 2.5 years to evaluate pattern-reversal and motion-onset visual evoked potentials (P-VEPs and M-VEPs), visually driven oddball event-related potentials (ERPs) and Montreal Cognitive Assessments. In addition to evaluating the intraindividual change in the observed parameters, we also compared patient data to data from eleven age- and gender-matched controls. We did not find any significant differences in P-VEPs between the patients and controls or in the paired comparison of the first and last visit. The only significant finding for P-VEPs was a linear trend in prolongation of the 20′ P-VEP P100 peak time. In M-VEPs, we found a significant intergroup difference in the N160 peak time recorded during the first visit for peripheral M-VEPs only. During the last visit, all N160 peak times for patients differed significantly from those of the control group. The only intervisit difference close to the level of significance was for peripheral M-VEPs, which confirmed the trend analysis. No significant differences between patients and controls were found in the ERPs, but the P300 peak time showed a significant difference between the first and last visits, as confirmed by the trend. Patient reaction time was not significantly delayed at the first visit; however, it was prolonged with time, as confirmed by the trend. Our aim was to evaluate whether antiretroviral treatment in HIV+ patients is sufficient to preserve brain visual function. The optic nerve and primary visual cortex function tested by the P-VEPs seem to be preserved. The prolongation of the M-VEPs suggests an individually detectable decline in CNS function, but these changes did not show a progression during the follow-up. From a longitudinal perspective, the trends in peak time prolongation of the 20′ P-VEP, peripheral M-VEP, ERP and reaction time suggest a faster decline than that caused by aging in healthy populations, as previously described in a cross-sectional study.

In adults, motion-onset visual evoked potentials (M-VEPs) with a dominant N2 peak represent a useful diagnostic tool. However, it is difficult to use this type of VEP in children because of the long maturation (up to 18 years) of M-VEPs, which is characterised by a gradual decrease in N2 peak latency and shape development. Moreover, in some children, M-VEPs are difficult to identify with standard stimuli. We tested features of M-VEPs in 30 children (7–12 years) with the following set of standard stimuli used in our lab for examining adults ( https://web.lfhk.cuni.cz/elf ): low-contrast translation motion (TM) and expansion/contraction motion (ExCoM) in full field and in periphery (with central 20° masked). In 16 children, a high-contrast TM was also tested. With standard (low-contrast) stimuli, a common M-VEP to TM and to ExCoM was detected in 77 and 83 % of children, respectively. The M-VEPs to ExCoM in the periphery were detected in only 43 % of children. An abnormal dominant P1 peak was found in 9 % of VEPs to TM, 12 % of VEPs to full-field ExCoM and 14 % of VEPs to peripheral ExCoM. The M-VEPs to all low-contrast stimuli displayed large inter-individual latency variability (N2 peak latency differed for more than 100 ms). High contrast (more suitable for the non-mature magnocellular pathway) shortened M-VEP latencies and improved amplitudes. Our findings show that the maturation of motion perception in children is inter-individually variable, which limits the diagnostic use of M-VEPs.

Gender is presumed to be one of the factors causing interindividual variability in the brain’s electrophysiological parameters. Our aim was to characterize the role of gender in visual evoked potentials (VEPs), event-related potentials (ERPs), visual mismatch negativity (vMMN) and the spectral characteristics of the EEG. We examined 42 healthy volunteers (21 women and 21 men, aged 20-29 years). We measured VEPs in response to pattern-reversal and motion-onset stimulation, ERPs in an oddball paradigm and vMMN in response to a combination of motion directions presented in the visual periphery. P100 peak latency for 40’ reversal VEPs was significantly shorter in women than in men as determined using a non-parametric Wilcoxon signed-rank test. In addition, women showed higher relative EEG spectral power in the alpha band (p=0.023) and lower power in the theta band (p=0.004). Our results in this small but homogeneous group of subjects confirm previously reported gender influences on pattern-reversal VEPs and the EEG frequency spectrum. Gender should be taken into consideration in establishing norms on these measures. We found no statistically significant differences between women and men for any of the other stimuli presented.

An electrophysiological study on the effect of aging on the visual pathway and various levels of visual information processing (primary cortex, associate visual motion processing cortex and cognitive cortical areas) was performed. We examined visual evoked potentials (VEPs) to pattern-reversal, motion-onset (translation and radial motion) and visual stimuli with a cognitive task (cognitive VEPs - P300 wave) at luminance of 17 cd/m(2). The most significant age-related change in a group of 150 healthy volunteers (15-85 years of age) was the increase in the P300 wave latency (2 ms per 1 year of age). Delays of the motion-onset VEPs (0.47 ms/year in translation and 0.46 ms/year in radial motion) and the pattern-reversal VEPs (0.26 ms/year) and the reductions of their amplitudes with increasing subject age (primarily in P300) were also found to be significant. The amplitude of the motion-onset VEPs to radial motion remained the most constant parameter with increasing age. Age-related changes were stronger in males. Our results indicate that cognitive VEPs, despite larger variability of their parameters, could be a useful criterion for an objective evaluation of the aging processes within the CNS. Possible differences in aging between the motion-processing system and the form-processing system within the visual pathway might be indicated by the more pronounced delay in the motion-onset VEPs and by their preserved size for radial motion (a biologically significant variant of motion) compared to the changes in pattern-reversal VEPs.

Visual-evoked potentials (VEPs) were used for objective testing of visual functions during treatment courses of Lyme neuroborreliosis (LNB) in adult patients in the Czech Republic. In 30 LNB patients with originally delayed VEP latencies, pattern-reversal (R-VEP) and motion onset (M-VEP) VEPs were repeatedly examined within 1 to 8 years. Six patients had Lyme optic neuritis (ON), five of them displayed prolonged latencies in both R-VEPs and M-VEPs, and one had only abnormal R-VEPs. The VEP recovery to normal latency values was in three of them. In the group of 24 LNB patients without ON, 14 patients displayed prolonged latencies only to motion stimuli, and 10 patients had abnormal latencies in both R-VEPs and M-VEPs. During the follow-up period, 7 patients displayed shortening to normal latencies. In 5 patients, VEPs latencies improved only partially, and in the remaining 12 patients, VEPs did not improve at all. This study provides objective evidence that in LNB, most of the patients without clinically manifesting ON display optic pathway involvement-predominantly magnocellular system/dorsal stream function changes. In patients with ON, however, mainly the parvocellular system is affected. About half of the patients without ON improved with a relatively long-time course of latency shortening.

Visual evoked potentials to motion-onset stimulation (M-VEPs) gradually attenuate in amplitude during examination. The observed decline in averaged responses can be caused by decreases in single response magnitudes and/or increased variability in a response delays, that is, latency jittering. To illuminate the origins of the suppression of M-VEPs during stimuli repetition, we used correlation technique to estimate an upper bound of possible latency jittering of single sweeps and we evaluated the effect of its correction on the amplitudes of three M-VEP dominant peaks P1, N2 and P3. During prolonged visual motion stimulation, the variability of corrective latency shifts in the occipital region increased (r = 0.35: 0.44) and the number of single responses corresponding to the average curve declined in occipital and parietal derivations (r = −0.48: −0.62). While the P1 peak amplitude did not exhibit any time-specific behaviour, the N2 amplitude exhibited a significant decay of 29.4 % that was partially reduced to 16.6 % in the central occipital derivation by the latency jitter and non-correspondence corrections. The strongest attenuation (32.7 %) was observed in the P3 amplitude and was less sensitive to the corrections, dropping only to 27.9 %. The main part of the response suppression to repeated motion stimulation was caused by amplitude drop and represents non-stationary process that likely correspond to a fatigue model. The rise of variability in latency jitter correction and the reduction in single responses correlated with the M-VEP were significant factors associated with prolonged motion stimulation. The relation of these parameters to a hypothetical veridical response is ambiguous and can be caused by a time shift of the response or by a change of signal-to-noise ratio. Using selective averaging and latency jitter correction, the effect of response suppression was partially removed.

Objective: The aim of this pilot study was to evaluate the efficacy of visual evoked potentials (VEPs) in the monitoring of visual function during a high-dose intravenous steroid pulse therapy and apheresis treatment of severe Graves' ophthalmopathy (GO). Patients and Research Design: Nine patients with severe and active GO were treated with high-dose methylprednisolone (1 g day−1 three times within 1 week, then 0.5 g day−1 seven times for 2 weeks) combined with plasma filtration (twice a week in weeks 1, 2, 4, 7, and 10). Pattern-reversal and motion-onset VEPs were examined three times, pretreatment, after steroid pulses, and after the last apheresis. Results: After 10 steroid pulses, the visual acuity was significantly better and the pattern-reversal VEP amplitudes (element size of only 20') had a similar trend for improvement. However, this effect disappeared after 7 weeks when only apheresis treatment was performed. No significant changes in the latencies of any of the tested VEP variants were found in relationship to the treatment. Conclusion: Only the observed large intraindividual variability of the VEP parameters between repeated examinations of patients with the shortest duration of GO might be recognized as a marker for functional changes of the visual pathway due to GO. Although this pilot study cannot provide a definite view on the usefulness of the extended set of VEPs in objective monitoring of GO, it seems that the steroid pulse therapy effect is detectable in contrast to the lack of influence by apheresis on the electrophysiological parameters tested. J. Clin. Apheresis 2012. © 2012 Wiley Periodicals, Inc.

Five children with a history of preterm birth (mean gestational age of 27 weeks; birth weight 870-1,380 g) and perinatal post-hemorrhagic hydrocephalus were examined ophthalmologically at ages ranging from 4-11 years. An extended visual evoked potentials (VEPs) examination was simultaneously performed, using pattern-reversal, motion-onset, and cognitive visual stimuli. Although 3 of the 10 eyes displayed about normal visual acuity (> or =0.9), all of the examined eyes were abnormal for at least one variant of the tested VEPs. Pathological changes in VEPs (missing responses, shape abnormalities due to delayed VEPs maturation, prolonged peak latencies, and reduced amplitudes) were roughly proportional to both gestational age and reduction in visual acuity. A more severe pathology was found in the motion-onset VEPs (in all five subjects - nine eyes) when compared to the pattern-reversal VEPs (in four subjects - eight eyes). These observations suggest that the magnocellular system/dorsal stream of the visual pathway (which is particularly activated in response to motion stimuli) may be more frequently affected in preterm children than the parvocellular system/ventral stream (tested mostly by the standard pattern-reversal VEPs). This pilot study may encourage further testing of the combined pattern and motion-related VEPs examinations in preterm children as a way of detecting hidden cortical/cerebral visual impairment (CVI).

We explored the effect of repeated visual stimulation on motion-onset visual evoked potentials (M-VEPs) during 25 min recording sessions in 10 subjects. The aim of the experiment was to determine influence of global motion adaptation (without motion-aftereffect) on intra-individual variability of M-VEPs and to suggest an optimal recording design for clinical examination. In addition to well described middle-time sensory adaptation, we also observed a long-time effect on motion specific N2 peak (155 ms). The N2 peak exhibited a strong relationship between its latency and inter-peak amplitude to the duration of recording in occipito-parietal derivations. In addition to the middle-term adaptation, N2 peak latency was prolonged by 10 ms and amplitude was attenuated by 30% with respect to the start of the experiment. An exponential model was employed to describe the dependency. The model can be used to reduce intra-individual variability during examination. Observed resemblance between the measured electrophysiological values and already published metabolic changes (glucose and oxygen utilization) during brain processing of visual information is discussed.

This review article summarises the research on the motion-onset visual evoked potentials (VEPs) and important motion stimulus parameters which have been clarified. For activation of the visual motion processing system and evocation of the motion-onset specific N2 peak (with latency of 160–200ms) from the extra-striate temporo-occipital and/or parietal cortex, the following stimulus parameters can be recently recommended: low luminance (

Pattern-reversal and motion-onset visual evoked potentials (VEPs) were simultaneously tested in a group of 70 healthy subjects between the ages of 6–60 years to verify suspected differences in maturation and aging dynamics of the pattern and motion processing subsystems of the visual pathway. The motion-onset VEPs displayed dramatic configuration development and shortening of latencies up to 18 years of age (correl. coeff. −0.85; p

Standard pattern-reversal visual evoked potentials (VEPs) and motion-onset VEPs (M-VEPs) were tested in 19 dyslexics and 19 normal readers aged 7–13 years in order to evaluate the feasibility of M-VEPs for the objective diagnostics of a visual subtype of dyslexia, in which a dysfunction of the magnocellular subsystem/dorsal stream of the visual pathway is suspected. The set of VEPs consisted of the pattern-reversal VEPs with check sizes of 20’, two types of translational motion (with low and high contrast) and two types of radial motion (in the full field or the periphery). While the P100 peak parameters in pattern-reversal VEPs did not differ between the group of dyslexics and controls, the group of dyslexics displayed significantly longer N2 latencies in all types of M-VEPs. Abnormal N2 latencies were found in 35–56% of dyslexics in different types of M-VEPs, with translational motion with high contrast being the most sensitive stimulation. A receiver operating characteristic analysis showed that the latencies of M-VEPs displayed higher discrimination potential than M-VEPs amplitudes. The study confirms a “magnocellular pathway/dorsal stream deficit” in approximately half of dyslexics.

Purpose Despite quite a long history of visual evoked potentials (VEPs), their use has been limited so far almost exclusively to flash or pattern related responses of the primary visual cortex (mediated mainly via activation of the parvocellular system of the visual pathway. It is surprising that efforts to extend it to more complex testing including an examination of the motion processing system (magnocellular system and dorsal stream) are quite rare (e.g. Kuba and Kubova, Doc Ophthalmol, 1992, 80, 83-89; Kubova et al., 1995, Vision Res, 35, 197-205. Methods Early or selective involvement of the motion processing system is suspected in many CNS disorders and we suggest that motion-onset VEPs may recognize functional problems of this kind better than imagine techniques (Kuba et al., Vision Res, 2007, 47, 189-202. Results Motion-onset VEPs display latency shortening up to the age of about 18 years representing very slow individually different maturation of the motion processing system (Langrova et al., Vision Res., 2006, 46, 536-544. In early adulthood they start accelerated latency prolongation when compared to pattern-reversal, which might be a good indicator of individual biological ageing (Kuba et al., Vision Res, 2012, 62, 9-16. Conclusion Since about 30% of pathological findings in our parallel pattern-reversal and motion-onset VEPs examinations in neuro-ophthalmological patients display exclusively the motion-onset VEPs pathology, we strongly recommend using them both in the theoretical vision research and ophthalmological diagnostics. Acknowledgement: Supported by the project PRVOUK - P37/07.

The manipulation of attention can produce mismatch negativity-like components that are not necessarily connected to the unintentional sensory registration of the violation of probability-based regularity. For clinical purposes, attentional bias should be quantified because it can vary substantially among subjects and can decrease the specificity of the examination. This experiment targets the role of attention in the generation of visual mismatch negativity (vMMN). The visual regularity was generated by a sequence of two radial motions while subjects focused on visual tasks in the central part of the display. Attentional load was systematically varied and had three levels, no-load, easy, and difficult. Rare, deviant, and frequent standard motions were presented with a 10/60 ratio in oddball sequences. Data from 12 subjects was recorded from 64 channels and processed. vMMN was identified within the interval of 142-198 ms. The mean amplitude was evaluated during the aforementioned interval in the parietal and fronto-central regions. A general linear model for repeated measures was applied to the mean amplitude with a three-factor design and showed a significant difference [F (1, 11) = 17.40, p = 0.002] between standard and deviant stimuli and between regions [F (1, 11) = 8.40, p = 0.01]; however, no significant effect of the task [F (2, 22) = 1.26, p = 0.30] was observed. The unintentional detection of irregularity during the processing of the visual motion was independent of the attentional load associated with handling the central visual task. The experiment did not demonstrate an effect of attentional load manipulation on mismatch negativity (MMN) induced by the motion-sequence, which supports the clinical utility of this examination. However, used stimulation paradigm should be further optimized to generate mismatch negativity that is stable enough to be usable not only for group comparisons but also for a single subject assessment.

We examined the visual and cognitive functions of a 72-year-old subject, KP, who recovered his sight after 53years of visual deprivation. We used visual evoked potentials (VEPs) to pattern-reversal and motion-onset stimuli and cognitive responses (ERPs) during the oddball paradigm to assess the effect of long-term deprivation on a mature visual system. KP lost his sight at the age of 17years, and light projection onto his right retina was restored at 71years by a corneal implant. Nine months after sight recovery we recorded reproducible responses to all examined stimuli. The response to pattern reversal contained two P100-like peaks with the later peak being dominant and significantly delayed (260ms) when compared to the P100s of two control subjects, to whom the stimuli were adjusted in size and contrast to mimic KP’s vision. KP’s motion-onset VEPs to full-field and peripheral stimuli had a characteristic shape with a well-defined N2 peak; however, both peaks were significantly delayed (262 and 272ms) compared to control responses. Unlike the P100 and N2 peaks, which represent sensory detection, the P3b/P300 component of the ERP to a target event in the oddball paradigm was not further delayed. In spite of degraded vision and sensory deprivation lasting 53years, KP displayed reproducible responses to all reported stimuli. Long-term visual deprivation and retinal detachment degraded KP’s visual sensory processing, assessed by pattern-reversal and motion-onset VEPs, whereas the cognitive processing of appropriate visual stimuli was not compromised.

Introduction In our previous papers (for review see Kuba et al., Vision Res., 2007, 47, 189–202) we have shown that in adults the motion-onset visual evoked potentials (M-VEPs) represent a useful diagnostic tool in neuro-opthalmology because they enable to test quite selectively the magnocellular system/dorsal stream function. In adults robust M-VEPs with low variability and typical shape with dominant negative N160 peak can be acquired easily, however, it is difficult to record and evaluate this type of VEPs in children. The M-VEPs go through very long maturation (up to 18 years of age) accompanied by gradual shortening of main negative peak latencies and also by age dependent shape development (Langrova et al., Vision Res., 2006, 46, 536–544). Moreover, they are unidentifiable to standard moving stimuli in some children. To understand better this problem, we tested 30 normal children aged 7–12 years. Methods We performed the set of standard stimuli used in our lab (https://www.lfhk.cuni.cz/elf) for examination of adults – low contrast translation motion (TM) and expansion/contraction motion (EXCOM). Results Reliable VEPs were detected in 77% of children to TM and in 83% of children to EXCOM. The dominant peak of the VEPs was negative in all TM VEPs and in 80% of EXCOM VEPs (positive in 20%). In both VEP types there was large inter-individual latency variability (in the range of 176–268 ms in TM and 176–290 ms in EXCOM). When a high contrast TM stimulus (non-optimal “magno” stimulus) was used, the M-VEP latencies shortened and amplitudes increased in majority of subjects. In contrast to adults, M-VEPs to peripheral stimulation (outside central 20°) were detectable only in 43% of children. Conclusions Our findings show that maturation of motion perception in children is rather inter-individually variable, which makes a diagnostic use of M-VEPs in children quite complicated. Acknowledgement Supported by the project PRVOUK - P37/07.

Purpose Optical coherence tomography (OCT) and Visual evoked potentials (VEPs) represent non-invasive objective examination of the visual system. While the OCT measures a morphological property of the retina (thickness of the retinal nerve fibre layer – RNFL), the VEP allows assessment a function of the visual system. There are numerous studies describing a mutual involvement of both mentioned aspects in diseases like multiple sclerosis, optic neuritis or glaucoma, however, normative studies of these relationship are missing. In our study we address this issue with an expectation to translate the findings into interpretation of pathological findings. Methods We examined a group of 20 healthy volunteers (14 females, 6 males) aged 19–23 years. For VEPs were used the following stimuli: standard checkerboard reversal stimulation with 60’ and 15’ check size and radial expansion/contraction motion of concentric rings. RNFL thickness was measured for superior, temporal, inferior and nasal retinal sectors in peripapilar circular scan using FD-OCT (Spectralis Heidelberg Engineering, Germany). The RNFL in each sector was compared with latency and amplitude of VEP dominant peaks (MedelecSynergy, Viasys Healthcare, USA). Results We found highly significant positive correlation between inferior sector of the RNFL thickness with P100-N145 interpeak amplitude for reversal R15’ ( r = 0.728; p r = 0.424; p = 0.006) and negative relationship to N160 interpeak amplitude ( r =−0.498; p = 0.01). The only correlation for the RNFL within the papilo-macular bundle was demonstrated for reversal 60′ N75-P100 interpeak amplitude ( r = 0.496; p = 0.001). This correlation was also seen for RNFL in temporal sector ( r = 0.412; p = 0.006). Conclusion In our study we demonstrated the relationship of some anatomic and function factors of visual system in healthy subjects. However, the interpretation of the relationship between inferior RNFL sector and VEPs amplitudes is not straightforward, as for VEPs recorded above the sulcus calcarinus just the upper hemiretina is dominant and so this topic is opened for further research. This study was supported by Grant Agency of the Czech Republic 309/09/0869 and by the P37/07 (PRVOUK) program.

Reports of visual functional impairment in spinocerebellar ataxia type 2 (SCA2) have been studied previously using pattern reversal visually evoked potentials (VEPs) with contradictory results. To provide additional evidence to this area, visual functions were studied using VEPs and event-related potentials (ERPs) in a group of ten patients with genetically verified SCA2. The electrophysiological examination included pattern reversal and motion-onset VEPs as well as visually driven oddball ERPs with an evaluation of a target and a pre-attentive response. In six patients, we found abnormal visual/cognitive processing that differed from normal values in latency, but not in the amplitude of the dominant VEP/ERP peaks. Among the VEPs/ERPs used, the motion-onset VEPs exhibited the highest sensitivity and showed a strong Spearman correlation to SCA2 duration (from r = 0.82 to r = 0.90, p < 0.001) and clinical state assessed by Brief Ataxia Rating Scale (from r = 0.71 (p = 0.022) to r = 0.80 (p < 0.001)). None of the VEP/ERP latencies showed a correlation to the triplet repeats of the SCA2 gene. In three patients, we did not find any visual/cognitive pathology, and one subject showed only a single subtle prolongation of the VEP peak. The observed visual/cognitive deficit was related to the subjects’ clinical state and the illness duration, but no relationship to the genetic marker of SCA2 was found. From the VEP/ERP types used, the motion-onset VEPs seems to be the most promising candidate for clinical state monitoring rather than a tool for early diagnostic use.

The authors tested visual-evoked potentials to pattern-reversal, motion-onset, and visual cognitive event-related potentials in 17 patients with mild-to-moderate Alzheimer's disease treated with Memantine (noncompetitive N-methyl-D-aspartic acid antagonist) to verify whether these objective methods can evaluate its therapeutic effect. The patients were examined before Memantine administration and after 3 and 6 months from the treatment onset. Besides electrophysiology, psychologic Alzheimer Disease Assessment Scale-cognitive part (ADAS-cog) test was also performed. Neither ADAS-cog nor any of the electrophysiological tests were able to prove a significant beneficial effect of Memantine therapy in our group of patients. The results of psychologic and electrophysiological tests did not correlate. An individual improvement of ADAS-cog score (decrease of score by 4 and more points) was present in only 29% of patients, improvement of event-related potentials (shortening of P300 peak latency by at least 20 milliseconds) occurred in 42% of patients. Conversely, in 52% of patients, Memantine therapy led to transitory decline of motion processing (delay of N2 peak latency of the motion-onset visual-evoked potentials by at least 10 milliseconds after the first 3 months of therapy, followed by return to pretherapy values in next 3 months).

The aim of our study was to verify reported visual dysfunctions of patients with Alzheimer disease with the use of several variants of VEPs and visual ERPs and to learn whether these methods can be useful in diagnostics of AD. We tested 15 patients (6 women and 9 men, aged from 58 to 87) with mild to moderate Alzheimer disease (12-23 points of Mini Mental State Examination) and 15 age, gender and education level matched controls. The examination consisted of VEPs to pattern-reversal and motion-onset stimulation (to translational and radial movement) and of visual ERPs recorded during an odd-ball test. The subjects were instructed to signalize target stimuli by pressing of a button, which enabled to evaluate also the reaction time. While pattern-reversal VEPs were comparable in patients and controls, there were significantly smaller N2 peak amplitudes of motion-onset VEPs in patients with AD (in particular in radial moving stimuli outside the central 20 deg of the visual field), which suggests a dysfunction of the motion-processing (magnocellular) system or the dorsal cortical stream. ERPs, having significantly longer latencies in patients than in controls, distinguished well both groups. However, the individual AD diagnostics based on ERPs seems to be limited by rather high inter-individual variability of the ERP latencies. The ERPs might, however, be useful in disease progress and therapy effect estimation. Electrophysiological parameters did not correlate with neuropsychological ADAS cog test (Alzheimer Disease Assessment Scale--cognitive part).

We explored morphological as well as functional and clinical markers of the vision processing in a cross-sectional study of subjects with Clinically Isolated Syndrome (CIS), often an early stage of the multiple sclerosis. Eighteen subjects (28 [19–47] years, 13 females) were examined within 3 years from the event. Recorded was RNFL thickness, pattern-reversal and motion-onset VEPs (P-VEPs and M-VEPs), low and high contrast Visual Acuity (VA). While the better eyes exhibited the only relevant correlation between age and latency of M-VEPs ( r = −0.59, p = 0.012), the worse eyes exhibited also correlation between the disease duration and latency of P-VEPs ( r = −0.66, p = 0.004) and M-VEPs ( r = −0.54, p = 0.021). Correlations of functional and clinical parameters to an average thickness of the RNFL or to the EDSS did not pass the significance level. In a pilot group of 18 CIS patients we did not find any relationship between clinical parameters and the RNFL, while the functional markers (P-VEP and M-VEP) correlated to the disease duration and seemingly paradoxically improved with the time. These findings confirm superior sensitivity of the functional examination.

Neuroborreliosis is a form of borreliosis that affects the central and/or peripheral nervous system. Although it can mimic neurologic and ophthalmologic disorders such as multiple sclerosis and optic neuritis, visual evoked potential (VEP) examination is usually not used in neuroborreliosis diagnostics. Combined VEP testing (pattern-reversal VEPs and VEPs produced in response to linear and radial motion) was performed in 81 patients with neuroborreliosis verified by laboratory results (positive polymerase chain reaction or intrathecal antibodies production). Thirty-four patients reported diplopia or blurred vision related to borreliosis. In 33 (40%) patients the VEPs were delayed: motion-onset VEPs were pathologic in 22 (27%) patients, reversal VEPs in 5 (6%) patients, and both VEP types in 6 (7%) patients. The findings suggest that VEP testing (especially the motion-onset VEP testing) can confirm CNS involvement. Much higher sensitivity of motion-onset VEPs in comparison with reversal VEPs can result from rather selective (earlier) involvement of the magnocellular system or the dorsal stream of the visual pathway.

The processing of visual motion was tested by means of event related potentials recording (ERP) using a paradigm designed to produce a visual mismatch negativity effect. The stimuli were unattended and presented in the peripheral visual field (outside the central 15 degrees). The standard stimulus consisted of an up/down motion sequence, whilst the deviant stimulus of a down/up motion sequence. Significant ERP differences between the standard and deviant conditions were found in 8 out of 10 adult subjects already in 80 ms and prevailingly in interval 145-260 ms from the initial stimulus presentation. The results demonstrate that the magnocellular information undergoes processing capable of detecting differences in the sequence of unattended peripheral motion stimuli.

Introduction The aim of our study was to verify the possibility of early identification of HIV-related neural injury using visual evoked potentials (VEPs) in neurologically asymptomatic HIV seropositives. In the CART (combination antiretroviral therapy) era, the prevalence of neurocognitive impairment remains high, up to 50%, and HIV-associated neurocognitive disorder (HAND) has shifted towards a milder clinical presentation. Such a mild clinical presentation can escape detection [1]. Methods The examination consisted of the Montreal Cognitive Assessment (MoCA) [2], and VEPs to pattern-reversal, motion-onset stimulation (radial movement), and of visual ERPs recorded during an odd-ball test (http://www.lfhk.cuni.cz/elf). Subjects: 9 homosexual men and 3 heterosexually infected women were examined in this study. All patients had ⩾350×106 CD4 cells/l blood at inclusion. The duration of the HIV infection was 0.5 – 7years, and mean age of the patients was 35 (24–50) years. Results P100 potential was recorded with no alteration in the VEP amplitude or latency. However, in 5 patients with CD4 counts 350–750×106cells/l, there was prolonged latency of the N160 peak compared to the reference values obtained in our laboratory, which suggests a dysfunction of the motion-processing (magnocellular system or the dorsal cortical stream) [3]. P300 latencies and MoCA results were within the normal range in all HIV patients. Conclusions Our data suggest that motion-onset VEPs may be a sensitive measure of subclinical visual pathway dysfunction in early HIV-1 infection, however, we did not reveal any cognitive decline in this pilot group. Subsequently, the patients will be investigated using VEPs and visual ERPs at six-month intervals to evaluate the long-term development of the visual pathway involvement in HIV patients.