PURPOSE: To describe the effect of dioptric blur on visual evoked potentials (VEPs) induced by motion onset (MO-VEPs). METHODS: The effect of dioptric blur up to 4 D on MO-VEPs was tested on 12 subjects using central, peripheral, and full-field stimulation with a low-contrast structure of concentric circles with spatial frequency <1 c/°. The results were compared to VEPs evoked by 15' and 60' checkerboard pattern-reversal (PR-VEPs). The relationship between peak time and interpeak amplitude of the dominant components was related to the level of dioptric blur using linear regression. RESULTS: The MO-VEPs did not show a significant peak prolongation (P > 0.28) or amplitude attenuation (P > 0.14) with the blur, whereas for the PR-VEPs we observed a significant decrease in amplitude (P < 0.001) and increase in peak time (P < 0.001) for both checkerboard sizes. CONCLUSIONS: For MO-VEPs induced by radial motion of low contrast and low spatial frequency pattern, the change in retinal blur does not affect the peak time or the interpeak amplitude of the dominant N2 component. TRANSLATIONAL RELEVANCE: The resistance to retinal blur that we demonstrated for MO-VEP provides a diagnostic opportunity to test the integrity of the visual system and reveal a retrobulbar impairment even in uncorrected refractive errors.

• MeSH
• lidé MeSH
• zrakové evokované potenciály * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

72 adult outpatients treated for epilepsy were examined by pattern reversal VEP method. 36 had generalized tonic-clonic seizures, 23 partial epilepsy with secondary tonic-clonic seizures and 13 had partial epilepsy with simple seizures. The patients were divided into three groups according to medical successfulness. The frequency of epileptic seizures per year was the criterion for dividing the group. Statistically significant relation was recorded in the occurrence of abnormal VEP findings to the frequency of epileptic seizures. Increased number of abnormal VEP findings occurred in the group of patients with greater frequency of epileptic seizures. The possible cause of the VEP abnormality in patients with frequent epileptic seizures is discussed.

• MeSH
• dospělí MeSH
• elektrická stimulace MeSH
• elektroencefalografie MeSH
• epilepsie komplexní parciální patofyziologie   MeSH
• epilepsie diagnóza   patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• počítačová rentgenová tomografie MeSH
• prognóza MeSH
• světelná stimulace MeSH
• zrakové evokované potenciály fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Motion-onset visual evoked potentials (MO VEPs) are robust to dioptric blur when low contrast and low spatial frequency patterns are used for stimulation. To reveal mechanisms of MO VEPs robustness, we studied whether the resistance to defocus persists even when using a high-contrast checkerboard using digital defocus in the emmetropic eyes of 13 subjects (males 20-60 years). We compared the dominant components of MO VEPs to pattern-reversal VEPs (PR VEP), which are sensitive to the blur. For stimulation, we used checkerboard patterns with 15´ and 60´ checks. To defocus the checkerboard, we rendered it with a second-order Zernike polynomial ( Z 2 0 ) with an equivalent defocus of 0, 2, or 4 D. For PR VEP, the checkerboards were reversed in terms of their contrast. To evoke MO VEP, the checkerboard of 60´ checks moved for 200 ms with a speed of 5 or 10 deg/s in the cardinal directions. The MO VEP did not change in peak time (P ≥ 0.0747) or interpeak amplitude (P > 0.0772) with digital blur. In contrast, for PR VEP, the results showed a decrease in interpeak amplitude (P ≤ 6.65ˑ10-4) and an increase in peak time (P ≤ 0.0385). Thus, we demonstrated that MO VEPs evoked by checkerboard, structure containing high spatial content, can be robust to defocus.

• Klíčová slova
• Digital blur, Motion-onset, Pattern-reversal, Visual evoked potential,
• MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• světelná stimulace MeSH
• vnímání pohybu fyziologie   MeSH
• zrakové evokované potenciály * fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

This study deals with the effect of stimulus contrast, between 1.3% and 96%, on the visual evoked potentials (VEPs) for onset of motion and for pattern reversal of checkerboard stimuli. The VEPs for pattern reversal and for the onset of motion both contain an initial positive peak (P1; peak latency about 120 msec) followed by a later negative peak (N2; peak latency 160-200 msec). However the P1 peak dominates the pattern-reversal VEP when recorded from the midline occipital lead, where it is maximal, while the N2 peak is larger in the motion-onset VEP, especially when recorded from unipolar lateral occipital leads. Whereas the amplitude of the P1 peak in both the pattern-reversal VEP and the motion-onset VEP decreases with decreasing contrast (becoming undetectable at a contrast of about 2% for the motion-onset VEP), the amplitude of the N2 peak in both types of VEP does not vary significantly with contrast, above a contrast of 1.3%. The increase in peak latency with decreasing contrast is also more pronounced for the positive than the negative peaks of both types of VEP. Taking into account the high contrast sensitivity of the magnocellular system (thought to be involved in the processing of motion) compared with the parvocellular system (probably more concerned with the processing of form), our findings suggest that for both motion-onset and pattern-reversal VEPs the negative peak is attributable to the motion-processing magnocellular pathway and the positive peak to the form-processing parvocellular system.

• MeSH
• časové faktory MeSH
• citlivost na kontrast fyziologie   MeSH
• dospělí MeSH
• lidé MeSH
• oční fixace MeSH
• rozpoznávání obrazu fyziologie   MeSH
• vnímání pohybu fyziologie   MeSH
• zrakové evokované potenciály fyziologie   MeSH
• zrakové korové centrum fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The effects of a standard 3 minutes' hyperventilation on the full-field pattern-reversal visual evoked potential (VEP) were studied in 33 normal subjects, 30 definite multiple sclerosis patients and in twenty-five patients with abnormal VEPs due to either tumourous compression of the anterior visual pathways or optic atrophy of other origin. Significantly greater reductions in P100 latency occurred in multiple sclerosis patients in comparison with controls (p less than 0.05). This change appeared to be specific for demyelinative type of lesion, for it was not found in cases with other types of pathology. Hyperventilation also increased the sensitivity of visual pathway impairment detection in multiple sclerosis.

• MeSH
• dospělí MeSH
• hyperventilace patofyziologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• zrakové evokované potenciály * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

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.

• MeSH
• Borrelia * MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• lineární modely MeSH
• lymská neuroborelióza diagnóza   patofyziologie   MeSH
• reakční čas fyziologie   MeSH
• retrospektivní studie MeSH
• rozpoznávání obrazu fyziologie   MeSH
• vnímání pohybu fyziologie   MeSH
• zrakové evokované potenciály fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

A rapid checkerboard pattern change is used to elicit pattern-reversal visual evoked potentials (PR VEPs). CRT or LCD monitors do not allow immediate reversal of the entire pattern. The study aimed to construct a new stimulator whose characteristics approximate an instantaneous reversal and verify whether the improvement is reflected in PR VEPs. A new stimulator using a matrix of 12 × 48 independent white square LEDs was designed and compared with LCDs and CRTs. The effect on the PR VEP peak times and amplitudes of N70, P100, and P140 waves was evaluated in ten subjects. The LED stimulator showed significantly better performance in the rate of change of illuminance, change of pattern, luminance settling and stability. The PR VEP amplitudes of N75, P100, and N140 did not show significant differences. The sum of interpeak amplitudes was significantly larger for the LCD than for the other monitors. The peak times of the waves evoked by the LED were shorter than those evoked by the LCD and CRT for the N75 wave and a check size of 30´. LED stimulators are a better alternative to CRTs for PR VEPs than current LCDs. LEDs also seem to be better than CRTs, but further research is necessary to obtain significant results.

• Publikační typ
• časopisecké články MeSH

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.

• MeSH
• aplikace orální MeSH
• chirurgická dekomprese MeSH
• dospělí MeSH
• Gravesova oftalmopatie farmakoterapie   patofyziologie   chirurgie   terapie   MeSH
• intravenózní imunoglobuliny terapeutické užití   MeSH
• intravenózní infuze MeSH
• kombinovaná terapie MeSH
• lidé středního věku MeSH
• lidé MeSH
• methylprednisolon aplikace a dávkování   terapeutické užití   MeSH
• monitorování léčiv metody   MeSH
• pilotní projekty MeSH
• prednison aplikace a dávkování   terapeutické užití   MeSH
• pulzní dávkování léků MeSH
• reakční čas MeSH
• separace krevních složek MeSH
• výsledek terapie MeSH
• zraková ostrost účinky léků   fyziologie   MeSH
• zrakové evokované potenciály * fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• Názvy látek
• intravenózní imunoglobuliny MeSH
• methylprednisolon MeSH
• prednison MeSH

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).

• MeSH
• dítě MeSH
• gestační stáří MeSH
• lidé MeSH
• nemoci centrálního nervového systému patofyziologie   MeSH
• novorozenec nedonošený MeSH
• novorozenec s nízkou porodní hmotností MeSH
• novorozenec MeSH
• pilotní projekty MeSH
• předškolní dítě MeSH
• refrakce oka fyziologie   MeSH
• zraková ostrost fyziologie   MeSH
• zrakové dráhy patofyziologie   MeSH
• zrakové evokované potenciály fyziologie   MeSH
• zrakové korové centrum patofyziologie   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In addition to standard pattern-reversal VEPs, the motion-onset VEPs were examined in 50 patients with acute unilateral retrobulbar neuritis (RN) and in 187 patients with possible or definite multiple sclerosis (MS). In MS patients (without sign or history of RN), the results of both types of VEPs correlated only partially. 26.2% of them displayed changes only in the motion-onset VEPs having the pattern-reversal VEPs completely normal. That is why we suppose that the magnocellular system (tested by motion-onset VEPs) can be affected by demyelination separately. In 28 patients with "pure" RN (without any other sign indicating demyelination disease) the always abnormal pattern-reversal VEPs were accompanied by delayed motion-onset VEPs in only 28.6% of patients. In contrast, much higher rate--68.2%--of delayed motion-onset VEPs was found in the 22 RN patients simultaneously suspected of MS These results indicate that RN affects predominantly the parvocellular visual system (tested by reversal VEPs). Distinct latency changes of the motion-onset VEP's in RN patients seem to signal a linkage between RN and demyelination.

• MeSH
• lidé MeSH
• pohyb těles MeSH
• roztroušená skleróza diagnóza   MeSH
• zánět zrakového nervu diagnóza   MeSH
• zrakové evokované potenciály * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH