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1.
Doc Ophthalmol ; 148(3): 155-166, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38622306

RESUMEN

PURPOSE: The aim of this neurophysiological study was to retrospectively analyze visual evoked potentials (VEPs) acquired during an examination for diagnosing optic nerve involvement in patients with Lyme neuroborreliosis (LNB). Attention was focused on LNB patients with peripheral facial palsy (PFP) and optic nerve involvement. METHODS: A total of 241 Czech patients were classified as having probable/definite LNB (193/48); of these, 57 were younger than 40 years, with a median age of 26.3 years, and 184 were older than 40 years, with a median age of 58.8 years. All patients underwent pattern-reversal (PVEP) and motion-onset (MVEP) VEP examinations. RESULTS: Abnormal VEP results were observed in 150/241 patients and were noted more often in patients over 40 years (p = 0.008). Muscle/joint problems and paresthesia were observed to be significantly more common in patients older than 40 years (p = 0.002, p = 0.030), in contrast to headache and decreased visual acuity, which were seen more often in patients younger than 40 years (p = 0.001, p = 0.033). Peripheral facial palsy was diagnosed in 26/241 LNB patients. Among patients with PFP, VEP peak times above the laboratory limit was observed in 22 (84.6%) individuals. Monitoring of patients with PFP and pathological VEP showed that the adjustment of visual system function occurred in half of the patients in one to more years, in contrast to faster recovery from peripheral facial palsy within months in most patients. CONCLUSION: In LNB patients, VEP helps to increase sensitivity of an early diagnostic process.


Asunto(s)
Potenciales Evocados Visuales , Neuroborreliosis de Lyme , Enfermedades del Nervio Óptico , Humanos , Neuroborreliosis de Lyme/fisiopatología , Neuroborreliosis de Lyme/diagnóstico , Neuroborreliosis de Lyme/complicaciones , Persona de Mediana Edad , Adulto , Potenciales Evocados Visuales/fisiología , Estudios Retrospectivos , Masculino , Femenino , Enfermedades del Nervio Óptico/fisiopatología , Enfermedades del Nervio Óptico/diagnóstico , Anciano , Adulto Joven , Adolescente , Parálisis Facial/fisiopatología , Parálisis Facial/diagnóstico , Niño , Anciano de 80 o más Años , Agudeza Visual/fisiología , Nervio Óptico/fisiopatología
2.
Bioconjug Chem ; 34(1): 133-139, 2023 01 18.
Artículo en Inglés | MEDLINE | ID: mdl-36519639

RESUMEN

Nucleosides and 2'-deoxyribonucleoside triphosphates (dNTPs) bearing 3,3'-dimethoxy-2,2'-diphenyl-6-(4-hydroxyphenyl)-bodipy fluorophore attached through a propargyl or propargyl-triethylene glycol linker to position 5 of 2'-deoxycytidine were designed and synthesized. They exerted bright red fluorescence and good sensitivity to viscosity changing their lifetime from 1.6 to 4.5 ns. The modifed dNTPs were substrates for DNA polymerases and were used in enzymatic synthesis of labeled DNA through primer extension. The modified DNA probes served as viscosity sensors responding to protein binding by changes of lifetime. The nucleotide with longer linker (dCpegMOBTP) was transported to live cells and incorporated into the genomic DNA, which can be useful for staining of DNA and imaging of DNA synthesis.


Asunto(s)
ADN , Nucleótidos , Viscosidad , ADN/metabolismo , ADN Polimerasa Dirigida por ADN , Nucleósidos
3.
Doc Ophthalmol ; 146(1): 79-91, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36436114

RESUMEN

INTRODUCTION: We developed a new portable device called "VEPpeak" for the examination of visual evoked potentials (VEPs) to extend VEP examination beyond specialized electrophysiological laboratories and to simplify the use of this objective, noninvasive, and low-cost method for diagnostics of visual and central nervous system dysfunctions. METHODS: VEPpeak consists of a plastic headset with a total weight of 390 g containing four EEG amplifiers, an A/D converter, a control unit, and a visual LED stimulator built in the front, vertically adjustable peak. The device is powered and controlled via USB connection from a standard PC/notebook using custom software for visual stimuli generation and for VEP recording and processing. Up to four electrodes can be placed at any scalp location or in combination with two dry electrodes incorporated into the headset. External visual stimulators, such as a tablet, can be used with synchronization. Feasibility and validation studies were conducted with 86 healthy subjects and 76 neuro-ophthalmological patients including 67 who were during the same session also tested with a conventional VEP system. RESULTS: VEPpeak recordings to standard (pattern-reversal) and non-standard (motion-onset, red-green alternation) were robust and repeatable and obtained also in immobilized patients. Good comparability of results was achieved between VEPpeak and standard examination. Some systematic differences in peak latencies and amplitudes are consistent with differences in stimulus characteristics of the two compared systems. DISCUSSION: VEPpeak provides an inexpensive system for clinical use requiring portability. In addition to ISCEV standard VEP protocols, free choice of stimuli and bio-signal recordings make the device universal for many electrophysiological purposes.


Asunto(s)
Potenciales Evocados Visuales , Corteza Visual , Humanos , Electrorretinografía , Corteza Visual/fisiología , Electrodos , Estimulación Luminosa
4.
Angew Chem Int Ed Engl ; 62(38): e202307548, 2023 09 18.
Artículo en Inglés | MEDLINE | ID: mdl-37498132

RESUMEN

A modified 2'-deoxycytidine triphosphate derivative (dCTO TP) bearing a thiazole orange moiety tethered via an oligoethylene glycol linker was designed and synthesized. The nucleotide was incorporated into DNA by DNA polymerases in vitro as well as in live cells. Upon incorporation of dCTO TP into DNA, the thiazole orange moiety exhibited a fluorescence lifetime that differed significantly from the non-incorporated (i.e. free and non-covalently intercalated) forms of dCTO TP. When dCTO TP was delivered into live U-2 OS cells using a synthetic nucleoside triphosphate transporter, it allowed us to distinguish and monitor cells that were actively synthesizing DNA in real time, from the very first moments after the treatment. We anticipate that this probe could be used to study chromatin organization and dynamics.


Asunto(s)
ADN , Nucleótidos , Fluorescencia , ADN/metabolismo , Benzotiazoles
5.
Org Biomol Chem ; 19(45): 9966-9974, 2021 11 25.
Artículo en Inglés | MEDLINE | ID: mdl-34747967

RESUMEN

We designed and synthesized nucleosides bearing aminophenyl- or aminonaphthyl-3-methoxychromone fluorophores attached at position 5 of cytosine or thymine and converted them to nucleoside triphosphates. The fluorophores showed solvatochromic fluorescence with strong fluorescence at 433-457 nm in non-polar solvents and very weak fluorescence at 567 nm in alcohols. The nucleosides and nucleotides also showed only negligible fluorescence in alcohols or water. The triphosphates were substrates for DNA polymerase in the enzymatic synthesis of modified DNA probes that showed only very weak fluorescence in aqueous buffer but a significant light-up and blue shift were observed when they interacted with proteins (histone H3.1 or p53 for double-stranded DNA probes or single-strand binding protein for single-stranded oligonucleotide probes). Hence, nucleotides have good potential in the construction of DNA sensors for studying protein-DNA interactions. The modified dNTPs were also transported into cells using a cyclodextrin-based transporter but they were not incorporated into the genomic DNA.


Asunto(s)
Cromonas/química , Sondas de ADN/química , ADN/química , Enzimas/química , Colorantes Fluorescentes/química , Nucleótidos/química , Proteínas/química , Fluorescencia , Unión Proteica
6.
Doc Ophthalmol ; 143(1): 17-31, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33392893

RESUMEN

BACKGROUND: For patients with age-related macular degeneration (AMD), a special intraocular lens implantation partially compensates for the loss in the central part of the visual field. For six months, we evaluated changes in neurophysiological parameters in patients implanted with a "Scharioth macula lens" (SML; a center near high add + 10 D and peripheral plano carrier bifocal lens designed to be located between the iris and an artificial lens). METHODS: Fourteen patients (5 M, 9 F, 63-87 years) with dry AMD were examined prior to and at 3 days after, as well as 1, 2, and 6 months after, implantation using pattern-reversal, motion-onset, and cognitive evoked potentials, psychophysical tests evaluating distant and near visual acuity, and contrast sensitivity. RESULTS: Near visual acuity without an external aid was significantly better six months after implantation than before implantation (Jaeger table median (lower; upper quartile): 4 (1; 6) vs. 15 (13; 17)). Distant visual acuity was significantly altered between the pre- (0.7 (0.5; 0.8) logMAR) and last postimplantation visits (0.8 (0.7; 0.8) logMAR), which matched prolongation of the P100 peak time (147 (135; 151) ms vs. 161 (141; 166) ms) of 15 arc min pattern-reversal VEPs and N2 peak time (191.5 (186.5; 214.5) ms vs. 205 (187; 218) ms) of peripheral motion-onset VEPs. CONCLUSION: SML implantation significantly improved near vision. We also observed a slight but significant decrease in distant and peripheral vision. The most efficient electrophysiological approach to test patients with SML was the peripheral motion-onset stimulation, which evoked repeatable and readable VEPs.


Asunto(s)
Lentes Intraoculares , Degeneración Macular , Electrorretinografía , Humanos , Implantación de Lentes Intraoculares , Agudeza Visual
7.
Chemistry ; 26(52): 11950-11954, 2020 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-32633433

RESUMEN

Thymidine triphosphate bearing benzylidene-tetrahydroxanthylium near-IR fluorophore linked to the 5-methyl group via triazole was synthesized through the CuAAC reaction and was used for polymerase synthesis of labelled DNA probes. The fluorophore lights up upon incorporation to DNA (up to 348-times) presumably due to interactions in major groove and the fluorescence further increases in the single-stranded oligonucleotide. The labelled dsDNA senses binding of small molecules and proteins by a strong decrease of fluorescence. The nucleotide was used as a light-up building block in real-time PCR for detection of SARS-CoV-2 virus.


Asunto(s)
COVID-19 , Replicación del ADN , Sondas de ADN , Humanos , Nucleótidos , SARS-CoV-2
8.
Doc Ophthalmol ; 139(2): 83-97, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-30993574

RESUMEN

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.


Asunto(s)
Cognición/fisiología , Potenciales Evocados Visuales/fisiología , Potenciales Evocados/fisiología , Infecciones por VIH/fisiopatología , Percepción de Movimiento/fisiología , Adulto , Antirretrovirales/uso terapéutico , Recuento de Linfocito CD4 , Estudios Transversales , Electrorretinografía , Femenino , Infecciones por VIH/tratamiento farmacológico , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Tiempo de Reacción/fisiología , Agudeza Visual/fisiología , Corteza Visual/fisiología , Adulto Joven
9.
Doc Ophthalmol ; 134(1): 45-55, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-28074347

RESUMEN

PURPOSE: The goal of the current study was to explore visual function in virally suppressed HIV patients undergoing combined antiretroviral therapy (cART) by using pattern-reversal and motion-onset visual evoked potentials (VEPs). METHODS: The pattern-reversal and motion-onset VEPs were recorded in 20 adult HIV+ patients with a mean age of 38 years and CD4 cell counts ≥230 × 106 cells/L of blood. RESULTS: Nine out of 20 patients displayed VEP abnormalities. Pattern-reversal VEPs pathology was observed in 20% of subjects, and 45% HIV patients had impaired motion-onset VEPs. Five out of 16 neurologically asymptomatic HIV patients had prolonged motion-onset VEP latencies in both eyes. Four neurologically symptomatic patients displayed simultaneously abnormal motion-onset and pattern-reversal VEP latencies: monocular involvement was observed in two patients with Lyme and cytomegalovirus unilateral optic neuritis. Binocular involvement was noted in two patients with cognitive deficits. Correlation analysis between disease duration, CD4 cell count, HIV copies in plasma, MoCA and electrophysiological parameters did not show any significant relationships. CONCLUSIONS: The functional changes of the visual system in neurologically asymptomatic virally suppressed HIV patients displayed higher motion-onset VEP sensitivity than in standard pattern-reversal VEP examinations. This promising marker, however, has no significant association with clinical conditions. Further exploration is warranted.


Asunto(s)
Potenciales Evocados Visuales/fisiología , Infecciones por VIH/fisiopatología , Percepción de Movimiento/fisiología , Reconocimiento Visual de Modelos/fisiología , Adulto , Análisis de Varianza , Antirretrovirales/uso terapéutico , Recuento de Linfocito CD4 , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/inmunología , Infecciones por VIH/virología , Humanos , Masculino , Persona de Mediana Edad , Neuritis Óptica/fisiopatología , Neuritis Óptica/virología , Carga Viral , Adulto Joven
10.
Doc Ophthalmol ; 133(3): 171-181, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27832406

RESUMEN

PURPOSE: The implantation of an intraocular telescope increases life quality in patients with end-stage age-related macular degeneration (AMD). The present study monitored changes in electrophysiological markers of visual processing before and during seventeen months after a novel mirror telescope implantation in two patients (OV-male 90 years, MZ-female 70 years) with the final-stage form of AMD. METHODS: Visual evoked potentials were recorded to high-contrast pattern-reversal (PR-VEP for check size 40' and 10'), low-contrast motion-onset stimuli (in visual periphery M-VEP M20°, and in central part M-VEP C8°), and event-related potentials (ERPs) in the oddball visual paradigm. RESULTS: MZ's more systematic responses showed attenuation and prolongation of the M-VEP M20° and the PR-VEP 40' immediately after the telescope implantation with a slow amplitude recovery with unchanged prolonged latency. The implantation completely eradicated the M-VEP C8° without any restoration. The PR-VEP 10' were not readable. Only a part of OV's PR-VEP 40' and M-VEP M20' were of a repeatable and expected morphology. These OV's VEPs were consistent with MZ's findings. The ERPs did not show any effect of implantation in both patients. Post-implantation visual acuity and reaction time overcame the pre-implantation levels. CONCLUSIONS: The mirror telescope preserved peripheral vision in contrast to classic telescopes; however, the telescope concurrently reduced the luminance of the magnified retinal image, which was likely responsible for the prolongation of the VEP latencies.


Asunto(s)
Potenciales Evocados Visuales , Lentes , Degeneración Macular , Telescopios , Percepción Visual/fisiología , Prótesis Visuales , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Degeneración Macular/fisiopatología , Degeneración Macular/rehabilitación , Masculino , Reconocimiento Visual de Modelos/fisiología , Agudeza Visual , Prótesis Visuales/normas
11.
Doc Ophthalmol ; 128(2): 121-9, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24563372

RESUMEN

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: Our findings show that the maturation of motion perception in children is inter-individually variable, which limits the diagnostic use of M-VEPs.


Asunto(s)
Potenciales Evocados Visuales/fisiología , Percepción de Movimiento/fisiología , Niño , Sensibilidad de Contraste/fisiología , Ojo/crecimiento & desarrollo , Femenino , Humanos , Masculino , Umbral Sensorial/fisiología , Corteza Visual/fisiología
12.
Psychiatry Res Neuroimaging ; 337: 111768, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38128365

RESUMEN

Despite positive prior results obtained by using event-related potentials (ERPs) in psychiatric patients, they are not routinely used in the clinical setting. This may in part be due to problems regarding a lack of transportable equipment availability. It can be difficult for these patients to repeatedly visit electrophysiological laboratories. To address this issue, we propose using a new, fully portable device for visually evoked potentials (VEP) and cognitive function assessment, that can be used for quick examinations (https://www.veppeak.com). Our device, called "VEPpeak", is built into a headset with a color LED visual stimulator. It weighs 390 g and is connected to a notebook (PC) with evaluation software via USB. In this pilot study, we verified the device's usability in 31 patients with schizophrenia. We used the oddball paradigm with the recognition of colors for the P300 wave and choice reaction time evaluation. The examination lasted only about ten minutes. The results indicated good reproducibility of large cognitive potentials (P300) with prolonged P300 latencies and reduced amplitudes in patients compared to 15 control subjects. The P300 latency and reaction time prolongation in patients correlated with their age and the sedative effect of the pharmacotherapy.


Asunto(s)
Potenciales Relacionados con Evento P300 , Psiquiatría , Humanos , Proyectos Piloto , Reproducibilidad de los Resultados , Potenciales Evocados/fisiología , Cognición/fisiología
13.
Acta Medica (Hradec Kralove) ; 66(2): 55-60, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37930094

RESUMEN

In the age homogenous group of 13 healthy volunteers, we examined visual evoked potentials (VEP) visually evoked cognitive potentials (event-related potentials - ERP) and choice reaction time (CRT) five times during the day (from 10.00 a.m. up to midnight) to verify whether there are significant changes of the measured parameters of the cortical evoked potentials and CRT which might reflect the level of the mental fatigue. The electrophysiological testing was done with the use of a new portable VEP device named "VEPpeak" enabling to perform the examination outside standard labs in almost any conditions. It was found that the latency of ERP (P300 peak time) and CRT displayed significant prolongation toward midnight while VEP latency and all amplitudes did not change significantly. This pilot study supports our idea that the portable VEP device possibly might be used for the objective examination of mental fatigue that is needed in many situations. This should be confirmed in a larger study also including a comparison with non-electrophysiological fatigue testing.


Asunto(s)
Potenciales Evocados Visuales , Potenciales Evocados , Humanos , Proyectos Piloto , Potenciales Evocados/fisiología , Cognición , Fatiga Mental
14.
J Clin Apher ; 27(6): 295-301, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22811284

RESUMEN

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.


Asunto(s)
Potenciales Evocados Visuales , Oftalmopatía de Graves/fisiopatología , Administración Oral , Adulto , Eliminación de Componentes Sanguíneos , Terapia Combinada , Descompresión Quirúrgica , Monitoreo de Drogas/métodos , Potenciales Evocados Visuales/fisiología , Femenino , Oftalmopatía de Graves/tratamiento farmacológico , Oftalmopatía de Graves/cirugía , Oftalmopatía de Graves/terapia , Humanos , Inmunoglobulinas Intravenosas/uso terapéutico , Infusiones Intravenosas , Metilprednisolona/administración & dosificación , Metilprednisolona/uso terapéutico , Persona de Mediana Edad , Proyectos Piloto , Prednisona/administración & dosificación , Prednisona/uso terapéutico , Quimioterapia por Pulso , Tiempo de Reacción , Resultado del Tratamiento , Agudeza Visual/efectos de los fármacos , Agudeza Visual/fisiología
15.
Cerebellum ; 10(1): 32-42, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20927662

RESUMEN

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.


Asunto(s)
Ataxias Espinocerebelosas/fisiopatología , Ataxias Espinocerebelosas/psicología , Percepción Visual/fisiología , Adulto , Edad de Inicio , Anciano , Envejecimiento/fisiología , ADN/genética , Electroencefalografía , Fenómenos Electrofisiológicos , Potenciales Evocados/fisiología , Potenciales Evocados Visuales/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Examen Neurológico , Reconocimiento Visual de Modelos/fisiología , Estimulación Luminosa , Procesamiento de Señales Asistido por Computador , Ataxias Espinocerebelosas/genética , Repeticiones de Trinucleótidos , Corteza Visual/fisiopatología , Adulto Joven
16.
Doc Ophthalmol ; 123(1): 51-7, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21647683

RESUMEN

OBJECTIVE: To present a unique case of a 34-year-old patient with unilateral functional visual loss after chemical burn with normal visual evoked potentials (VEPs) and absent cognitive response (P300 wave). METHODS: Visual functions, complete ophthalmic and neurologic examinations including computed tomography of the brain, electrophysiological testing of the visual pathway up to the cognitive brain cortex were evaluated. Data were collected prospectively during 1-year follow-up and compared with data from published case series and a literature review. RESULTS: No abnormalities were found that could account for such a rapid monocular loss of vision with exception of absence of the P300 wave in the affected eye during cognitive tasks. Vision slowly improved during 1 year without any treatment. CONCLUSIONS: Functional vision loss is a diagnosis of exclusion. In the event of reduced vision in the context of a normal ocular health examination, all other pathology must be ruled out before the diagnosis of functional visual loss is established. Complex visual electrophysiological testing is the preferred tool for objective examination of such disorders.


Asunto(s)
Quemaduras Químicas/fisiopatología , Trastornos del Conocimiento/fisiopatología , Quemaduras Oculares/inducido químicamente , Umbral Sensorial/fisiología , Trastornos de la Visión/fisiopatología , Adulto , Electrorretinografía , Potenciales Evocados Visuales/fisiología , Humanos , Masculino , Estudios Prospectivos , Retina/fisiología , Agudeza Visual/fisiología , Pruebas del Campo Visual , Campos Visuales
17.
Acta Neurobiol Exp (Wars) ; 68(1): 97-102, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18389020

RESUMEN

The objective of this study was to verify hypothesised changes in event related potentials (visual mismatch negativity, vMMN) in 17 subjects dependent on methamphetamine (MAMP) compared to age and gender matched 17 healthy volunteers. We found a significant correlation between vMMN and duration of methamphetamine abuse (Spearman correlation coefficient r=0.54-0.78; P<.05). The positive correlation indicates drop of originally more negative response to deviant stimulus, what may indicate a pre-attentive processing enhancement in the first years of MAMP abuse with its decease later on. Accordingly, post-hoc analysis revealed significantly stronger vMMN in patients with length of MAMP abuse shorter than 5 years than in paired controls. There were no such differences in abusers with the length of abuse longer than 5 years. The results show that the visual processing on the pre-attentional level can be influenced by long-term MAMP abuse, what can be specifically assessed by vMMN.


Asunto(s)
Trastornos Relacionados con Anfetaminas/fisiopatología , Variación Contingente Negativa/fisiología , Potenciales Evocados Auditivos/fisiología , Estimulación Acústica/métodos , Adulto , Estudios de Casos y Controles , Electroencefalografía/métodos , Femenino , Humanos , Masculino , Proyectos Piloto , Psicofísica , Análisis de Regresión , Factores de Tiempo
18.
J Clin Neurophysiol ; 23(5): 416-20, 2006 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17016151

RESUMEN

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.


Asunto(s)
Borrelia , Potenciales Evocados Visuales/fisiología , Neuroborreliosis de Lyme/diagnóstico , Neuroborreliosis de Lyme/fisiopatología , Percepción de Movimiento/fisiología , Reconocimiento Visual de Modelos/fisiología , Adulto , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Tiempo de Reacción/fisiología , Estudios Retrospectivos
19.
Vision Res ; 111(Pt A): 97-104, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25913026

RESUMEN

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.


Asunto(s)
Dislexia/fisiopatología , Potenciales Evocados Visuales/fisiología , Vías Visuales/fisiopatología , Adolescente , Estudios de Casos y Controles , Niño , Femenino , Humanos , Masculino , Percepción de Movimiento/fisiología , Umbral Sensorial/fisiología , Corteza Visual/fisiología
20.
Front Hum Neurosci ; 7: 411, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23908621

RESUMEN

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.

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