Grating visual acuity impairment assessed by sweep visually evoked potentials in children with optic pathway tumors unable to perform optotype acuity tests / Deficiência na acuidade visual de grades avaliada pelos potenciais visuais evocados de varredura em crianças com tumores da via óptica incapazes de informar a acuidade de optotipos

ABSTRACT Purpose: To determine visual impairment due to optic pathway tumors in children unable to perform recognition acuity tests. Methods: Grating visual acuity scores, in logMAR, were obtained by sweep visually evoked potentials (SVEP) in children with optic pathway tumors. The binocular grating visual acuity deficit was calculated by comparison with age-based norms and then assigned to categories of visual impairment as mild (from 0.10 to 0.39 logMAR), moderate (from 0.40 to 0.79 logMAR), or severe (≥0.80 logMAR). Interocular differences were calculated by subtraction and considered increased if >0.10 logMAR. Results: The participants were 25 children (13 boys; mean ± SD age, 35.1 ± 25.9 months; median age, 32.0 months) with optic pathway tumors (24 gliomas and 1 embryonal tumor), mostly located at the hypothalamic-chiasmatic transition (n=21; 84.0%) with visual abnormalities reported by parents (n=17; 68.0%). The mean grating acuity deficit was 0.60 ± 0.36 logMAR (median, 0.56 logMAR). Visual impairment was detected in all cases and was classified as mild in 10 (40.0%), moderate in 8 (32.0%), and severe in 7 (28.0%) children, along with increased interocular differences (>0.1 logMAR) (n=16; 64.0%). The remarkable ophthalmological abnormalities were nystagmus (n=17; 68.0%), optic disc cupping and/or pallor (n=13; 52.0%), strabismus (n=12; 48.0%), and poor visual behavior (n=9; 36.0%). Conclusion: In children with optic pathway tumors who were unable to perform recognition acuity tests, it was possible to quantify visual impairment by sweep-visually evoked potentials and to evaluate interocular differences in acuity. The severity of age-based grating visual acuity deficit and interocular differences was in accordance with ophthalmological abnormalities and neuroimaging results. Grating visual acuity deficit is useful for characterizing visual status in children with optic pathway tumors and for supporting neuro-oncologic management.(AU)

RESUMO Objetivo: Determinar o grau de deficiência visual em crianças com tumores da via óptica incapazes de informar a acuidade visual de reconhecimento. Método: A acuidade visual de grades, em logMAR, foi estimada por potenciais visuais evocados de varredura em crianças com tumores das vias ópticas. O déficit da acuidade visual de grades binocular foi calculado em relação ao valor mediano normativo esperado para a idade e a deficiência visual, classificada como leve (0,10 a 0,39 logMAR), moderada (0,40 a 0,79 logMAR) ou grave (≥0,80 logMAR). Diferenças inter-oculares foram calculadas por subtração e consideradas aumentadas se >0,10 logMAR. Resultados: Foram avaliadas 25 crianças (13 meninos; média de idade ± DP=35,1± 25,9 meses; mediana=32,0 meses) com tumores da via óptica (24 gliomas e 1 tumor embrionário) localizados particularmente na transição hipotalâmico-quiasmática (n=21; 84,0%) e com anormalidades visuais detectadas pelos pais (n=17; 68,0%). A média do déficit da acuidade de grades foi 0,60 ± 0,36 logMAR (mediana=0,56 logMAR). Observou-se deficiência visual leve em 10 (40,0%), moderada em 8 (32,0%) e grave em 7 (28,0%), além de aumento da diferença interocular da acuidade visual (n=16; 64,0%). As principais alterações oftalmológicas encontradas foram: nistagmo (n=17; 68,0%), aumento da escavação do disco óptico e/ou palidez (n=13; 52,0%), estrabismo (n=12; 48,0%) e comportamento visual pobre (n=9; 36,0%). Conclusão: Em crianças com tumor da via óptica e incapazes de responder aos testes de acuidade visual de reconhecimento, foi possível quantificar deficiência visual por meio dos potenciais visuais evocados de varredura e avaliar a diferença interocular da acuidade visual de grades. A gravidade do déficit da acuidade visual de grades relacionado à idade e a diferença interocular da acuidade visual de grades foram congruentes com alterações oftalmológicas e neuroimagem. O déficit da acuidade visual de grades foi útil à caracterização do estado visual em crianças com tumores da via óptica e ao embasamento da assistência neuro-oncológica.(AU)

The application of mr dti in cerebra infarction of optic radiation / 实用放射学杂志

Objective To evaluate the fiber altering and clinical relationship in patients with occipital and temporal lobe cerebral infarction with DTI.Methods Fifty patients suffering from cerebral stroke were analyzed with conventional MRI,DWI and DTI. The fibers of visual pathway were depicted ,and their fractional anisotropy (FA),apparent diffusion coefficient (ADC),isotropic im-age (Iso)and T2-weighted trace were measured and analyzed.Results Regions of interest (ROIs)were placed in infarction and nor-mal contralateral tissue for tracking the visual pathways.The different parameters were measured.FA is useful to differentiate hy-per-acute stroke from acute and sub-acute stroke.FA values increased slightly in hyper-acute and decreased in acute,sub-acute and chronic phase.The values of ADC in infarction regions in hyper-acute,acute and sub-acute phases were lower than those of the con-tralateral tissue.Iso and T2-weighted trace increased in acute phase and decreased in chronic phase.DTT was used to show the way and chang of visual pathway.Conclusion DTI could track the fiber of visual pathway,and depict the fiber of infarction zone.DTT could be used in evaluating the prognosis of patients.

Contrast sensitivity of pattern transient VEP components: contribution from M and P pathways

The purpose of this study was to compare contrast sensitivity estimated from transient visual evoked potentials (VEPs) elicited by achromatic pattern-reversal and pattern-onset/offset modes. The stimuli were 2-cpd, achromatic horizontal gratings presented either as a 1 Hz pattern reversal or a 300 ms onset/700 ms offset stimulus. Contrast thresholds were estimated by linear regression to amplitudes of VEP components vs. the logarithm of the stimulus contrasts, and these regressions were extrapolated to the zero amplitude level. Contrast sensitivity was defined as the inverse of contrast threshold. For pattern reversal, the relation between the P100 amplitude and log of the stimulus contrast was best described by two separate linear regressions. For the N135 component, a single straight line was sufficient. In the case of pattern onset/offset for both the C1 and C2 components, single straight lines described their amplitude vs. log contrast relations in the medium-to-low contrast range. Some saturation was observed for C2 components. The contrast sensitivity estimated from the low-contrast limb of the P100, from the N135, and from the C2 were all similar but higher than those obtained from the high-contrast limb of the P100 and C1 data, which were also similar to each other. With 2 cpd stimuli, a mechanism possibly driven by the M pathway appeared to contribute to the P100 component at medium-to-low contrasts and to the N135 and C2 components at all contrast levels, whereas another mechanism, possibly driven by the P and M pathways, appeared to contribute to the P100 component at high contrast and C1 component at all contrast levels...

Visual pathway abnormalities were found in most multiple sclerosis patients despite history of previous optic neuritis / Anormalidades nas vias visuais foram encontradas na maior parte dos pacientes com esclerose multipla independentemente da historia de neurite optica

Objective It was to investigate visual field (VF) abnormalities in a group of multiple sclerosis (MS) patients in the remission phase and the presence of magnetic resonance imaging (MRI) lesions in the optic radiations. Methods VF was assessed in 60 participants (age range 20-51 years): 35 relapsing-remitting MS patients [20 optic neuritis (+), 15 optic neuritis (-)] and 25 controls. MRI (3-Tesla) was obtained in all patients. Results Visual parameters were abnormal in MS patients as compared to controls. The majority of VF defects were diffuse. All patients except one had posterior visual pathways lesions. No significant difference in lesion number, length and distribution was noted between patients with and without history of optic neuritis. One patient presented homonymous hemianopsia. Conclusion Posterior visual pathway abnormalities were found in most MS patients despite history of previous optic neuritis. .

Objetivo Foi analisar o campo visual (CV) de um grupo de pacientes com esclerose múltipla (EM) na fase remissiva e a presença de lesões nas imagens de ressonância magnética (MRI) na radiação óptica. Método O CV foi estudado em 60 participantes (faixa etária de 20-51 anos): 35 pacientes EM remitente-recorrente: [20 neurite óptica (+), 15 neurite óptica (-)] e 25 controles. Foram obtidas MRI (3-Tesla) de todos os pacientes. Resultados Havia alterações visuais nos pacientes com EM quando comparados aos controles. A maioria apresentava defeitos difusos de CV. Todos os pacientes, à exceção de um, apresentaram lesões nas vias visuais posteriores. Não foi observada diferença significativa quanto a número, extensão e distribuição das lesões entre os pacientes com e sem história de neurite óptica. Um paciente apresentou hemianopsia homônima. Conclusão Anormalidades nas via visuais posteriores foram encontradas na maior parte dos pacientes com EM independentemente da história de neurite óptica. .

Evaluation of magnocellular pathway abnormalities in schizophrenia: a frequency doubling technology study and clinical implications / Avaliação das alterações da via magnocelular na esquizofrenia usando FDT e suas implicações clínicas

BACKGROUND: Visual processing deficits have been reported for patients with schizophrenia. Previous studies demonstrated differences in early-stage processing of schizophrenics, although the nature, extent, and localization of the disturbance are unknown. The magnocellular and parvocellular visual pathways are associated with transient and sustained channels, but their respective contributions to schizophrenia-related visual deficits remains controversial. PURPOSE: The aim of this study was to evaluate magnocellular dysfunction in schizophrenia using frequency doubling technology. METHODS: Thirty-one patients with schizophrenia and 34 healthy volunteers were examined. Frequency doubling technology testing was performed in one session, consisting of a 15-minute screening strategy followed by the C-20 program for frequency doubling technology. RESULTS: Schizophrenic patients showed lower global mean sensitivity (30,97 ± 2,25 dB) compared with controls (32,17 ± 3,08 dB), p<0.009. Although there was no difference in the delta sensitivity of hemispheres, there was a difference in sensitivity analysis of the fibers crossing the optic chiasm, with lower mean sensitivity in the patient group (28,80 dB) versus controls (30,66 dB). The difference was higher in fibers that do not cross the optic chiasm, with lower mean sensitivity in patients (27,61 dB) versus controls (30,26 dB), p<0.005. CONCLUSIONS: Our results suggest that there are differences between global sensitivity and fiber sensitivity measured by frequency doubling technology. The different sensitivity of fibers that do not cross the optic chiasm is consistent with most current etiological hypotheses for schizophrenia. The decreased sensitivity responses in the optic radiations may significantly contribute to research assessing early-stage visual processing deficits for patients with schizophrenia.

HISTÓRICO: Déficits de processamento visual foram relatados em pacientes com esquizofrenia. Estudos anteriores demonstraram diferenças no estágio inicial de processamento de esquizofrênicos, embora a natureza, extensão e localização do distúrbio são desconhecidas. As vias magnocelulares e parvocelular visuais são associados com canais transitórios e sustentado, mas suas respectivas contribuições para a esquizofrenia relacionados com déficits visuais permanece controverso. OBJETIVO: Avaliar a disfunção magnocelular na esquizofrenia usando a tecnologia de frequência dupla. MÉTODOS: Trinta e um pacientes com esquizofrenia e 34 voluntários saudáveis ​​foram examinados. Tecnologia de frequência dupla foi realizada em uma sessão, consistindo de uma estratégia de rastreio de 15 minutos, seguido do programa de C-20 para tecnologia de frequência dupla. RESULTADOS: Os pacientes esquizofrênicos apresentaram sensibilidade média inferior global (30,97 ± 2,25 dB), em comparação com os controles (32,17 ± 3,08 dB), p<0,009. Embora não tenha ocorrido diferença na sensibilidade do delta de hemisférios, houve uma diferença na análise de sensibilidade das fibras que atravessam a quiasma, com menor sensibilidade média no grupo de pacientes (28,80 dB) versus controlos (30,66 dB). A diferença foi maior em fibras que não cruzam o quiasma óptico, com menor sensibilidade média em pacientes (27,61 dB) versus controles (30,26 dB), p<0,005. CONCLUSÕES: Nossos resultados sugerem que há diferenças entre a sensibilidade global e sensibilidade da fibra medida pela tecnologia de frequência dupla. A sensibilidade diferente de fibras que não cruzam o quiasma óptico é compatível com a maioria das atuais hipóteses etiológicas para a esquizofrenia. As respostas diminuição da sensibilidade nas radiações ópticas podem contribuir significativamente para pesquisar a avaliação em estágio inicial déficits de processamento visual em pacientes com esquizofrenia.

Visual contrast sensitivity in tonic-clonic epileptic patients

We measured the effects of epilepsy on visual contrast sensitivity to linear and vertical sine-wave gratings. Sixteen female adults, aged 21 to 50 years, comprised the sample in this study, including eight adults with generalized tonic-clonic seizure-type epilepsy and eight age-matched controls without epilepsy. Contrast threshold was measured using a temporal two-alternative forced-choice binocular psychophysical method at a distance of 150 cm from the stimuli, with a mean luminance of 40.1 cd/m². A one-way analysis of variance (ANOVA) applied to the linear contrast threshold showed significant differences between groups (F[3,188] = 14.829; p < .05). Adults with epilepsy had higher contrast thresholds (1.45, 1.04, and 1.18 times for frequencies of 0.25, 2.0, and 8.0 cycles per degree of visual angle, respectively). The Tukey Honestly Significant Difference post hoc test showed significant differences (p < .05) for all of the tested spatial frequencies. The largest difference between groups was in the lowest spatial frequency. Therefore, epilepsy may cause more damage to the neural pathways that process low spatial frequencies. However, epilepsy probably alters both the magnocellular visual pathway, which processes low spatial frequencies, and the parvocellular visual pathway, which processes high spatial frequencies. The experimental group had lower visual contrast sensitivity to all tested spatial frequencies.

Pattern-reversal electroretinograms for the diagnosis and management of disorders of the anterior visual pathway / Eletroretinograma de padrão reverso no diagnóstico e acompanhamento das afecções da via óptica anterior

The pattern electroretinogram is an electrophysiological test that assesses the function of inner retinal layers, particularly the ganglion cells layer of retina, using a reversing checkerboard or grating pattern that produces no change in average luminance over time. The normal pattern electroretinogram is composed of a proeminent positive component (P50) and a large later negative component (N95). Since structural damage that compromises the retinal ganglion cell layer can lead to pattern electroretinogram changes, particularly in the N95 amplitude, the test can be useful in the treatment of a number of anterior visual pathway diseases. In this article, we review the methods for recording pattern electroretinogram and its usefulness in the diagnosis and management of diseases including inflammatory, hereditary, ischemic and compressive lesions of the anterior visual pathway.

O eletroretinograma de padrão reverso é um teste eletrofisiológico que avalia a função das camadas internas da retina, especialmente a camada de células ganglionares, através de um estímulo em xadrez ou em barras que não apresenta variação na luminância do estímulo. É composto de um componente positivo (P50) e um componente negativo (N95) tardio. Uma vez que lesões estruturais às células ganglionares da reitna podem levar a alterações no eletroretinograma de padrão reverso, especialmente na amplitude da onda N95, o teste pode ser útil no tratamento de várias doenças da via óptica anterior. Neste artigo revisamos os métodos de obtenção do eletroretinograma de padrão reverso e a sua utilidade no diagnóstico e acompanhamento de doenças incluindo lesões inflamatórias, hereditárias, isquemicas e compressivas na via óptica anterior.

Measurement of optic tracts in normal Chinese adults of the Han nationality based on the high-resolution MRI / 中华放射学杂志

Objective To explore the morphological characteristics of optic tracts in healthy Chinese Han adults on the high-resolution MRI and fill the database of Chinese standard brain with morphological data of optic tracts.Methods Cerebral MRI scans with T1 WI 3D MPRAGE sequence of 1000 healthy Chinese volunteers from 15 hospitals were divided into five stages, ranging in age from 18 to 70.With the technique of multi-baseline, structure and morphology of optic tracts were displayed optimally on the images with multiplanar reconstruction.Data were measured as following: transverse distance of the cisternal optic tract (TD1) and peri-crural optic tract (TD2), length from the cisternal optic tract to the peri-crural optic tract (L) ,angle between optic tract(AOT) and height of optic tract from its first segment to plane of anterior commissure (H) including H1, H2, H3, H4 and HS.The measurements of optic tracts between sexualities and among age groups were compared by anasis of covariance; those among five age groups were compared pairwisedly by least significant difference analysis (LSD); and the differences of measurements between left and right optic tracts were analyzed using paired t test.Results (1) Comparisons of optic tract structures between male and female: the mean optic tract length of male [(11.69±1.45),(11.56±1.44) mm] was significant longer than that of female [(10.58±1.29),(10.40±1.34) mm] (F=22.236, 29.703, P=0.000); the mean H1 of male [(2.56±0.28),(2.60±0.29) mm] and female [(2.57±0.31 ), (2.63±0.32) mm] were significantly different ( F =11.130,7.805, P = 0.000, 0.005).No significant differences of the other measurements were found between male and female ( P > 0.05 ).(2) Comparisons among age groups: among 5 age groups, TD1 of both sides [left TD1 :(4.64±0.51 ), (4.64±0.57), (4.55±0.58), (4.39±0.53), (4.36±0.58)mm;right TD1 :(4.84±0.53) ,(4.80±0.60), (4.77±0.65), (4.60±0.59), (4.57±0.59) mm] and the right TD2[(3.33±0.45),(3.34±0.41),(3.33±0.36),(3.23±0.38),(3.23±0.39) mm] had statistical differences ( F = 3.458, 2.735, 4.711, P = 0.008,0.028, 0.001 ).The LSD analysis found that the 50 years old group was the watershed with significant differences ( P < 0.05 ).The results also showed that the L of both sides had statistical differences among 5 age groups ( F = 14.510,14.532, P = 0.000).The LSD analysis found that the 60 years old group was the watershed with significant differences (P <0.05).Left TD2 and the H1-H5 of both sides had no significant differences among age groups ( P >0.05).(3) Comparisons of the measurements between left and right optic tracts: TD1 of bilateral optic tracts were (4.52±0.57)and(4.72±0.60) mm respectively; H1 of bilateral optic tracts were (2.56±0.30)and (2.61±0.30) mm respectively; H2 of bilateral optic tracts were (2.66±0.30)and (2.70±0.30) mm respectively; and L of bilateral optic tracts were ( 11.14±1.47 ) and ( 10.98±1.50 )mm respectively.There were significant differences in these measurements between left and right optic tracts( t =12.460, - 6.013,5.595,4.784, P = 0.000 ), while there were no significant differences in TD2, H3, H4 and H5( P > 0.05 ).Conclusions With high-resolution MR1 and 3D reconstruction, optic tract can be displayed clearly and measured accurately.There are definite differences in anterior segments of optic tracts between sexualities, sides and among ages in normal Chinese Han adults, while the posterior segments of optic tracts keep stable.Normal reference values of optic tracts in Chinese Han adults are provided to clinical practices and scientific researches, which are valuable for building of Chinese standard brain.

Retinal nerve fiber layer loss documented by optical coherence tomography in patients with optic tract lesions / Perda da camada de fibras nervosas retinianas documentada pela tomografia por coerência óptica em pacientes com lesões do trato óptico

PURPOSE: To report abnormalities of retinal nerve fiber layer (RNFL) thickness using Stratus - optical coherence tomography (OCT) in two patients with optic tract lesions. METHODS: Two patients with long standing homonymous hemianopia from optic tract lesions were submitted to a complete neuro-ophthalmic evaluation and to Stratus -optical coherence tomography examination. RESULTS: Both patients revealed diffuse loss of the RNFL at Stratus - OCT in both eyes. In the eyes with the temporal hemianopia, RFNL loss was diffuse but predominantly in the nasal and temporal areas of the optic disc, the classic pattern of band atrophy of the optic nerve. In the eyes with nasal hemianopia RNFL loss could be documented in the superior and inferior quadrants of the optic disc. RNFL loss correlated well with visual field loss and the expected pattern of RNFL loss in optic tract lesions. CONCLUSION: Stratus-Optical coherence tomography can provide useful information in the diagnosis of optic tract lesions by identifying the characteristic pattern of RNFL loss that occurs in both eyes in this condition.

OBJETIVO: Relatar alterações na camada de fibras nervosas retiniana (CFNR) com o uso da tomografia por coerência óptica (TCO) Stratus em pacientes com lesões do trato óptico. MÉTODOS: Dois pacientes com hemianopsia homônima de longa duração decorrente de lesões do trato óptico foram submetidos a avaliação neuroftalmológica completa e tomografia por coerência óptica Stratus. RESULTADOS: Ambos pacientes demonstraram redução difusa da CFNR nos dois olhos. Nos olhos com a hemianopsia temoporal, a perda da CFNR foi difusa mas com predomínio nas áreas nasal e temporal do disco óptico, um padrão clássico da atrofia em banda do nervo óptico. Nos olhos com hemianopsia nasal observou-se perda da CFNR nos quadrantes superior e inferior do disco óptico. A perda da CFNR se correlacionou com o defeito de campo visual e com o padrão esperado de perda da CFNR nas lesões do trato óptico. CONCLUSÃO: A tomografia por coerência óptica - Stratus pode fornecer informação útil no diagnóstico das lesões do trato óptico ao identificar o padrão característico de perda da CFNR que ocorre em ambos os olhos nesta condição.

fMRI combined with diffusion tensor imaging for diseases of posterior visual pathways / 第三军医大学学报

Objective To explore the relationship between structure and function in the diseases of posterior visual pathways as well as the anatomic mechanism of the abnormal visual responses.Methods Eleven cases of diseases of posterior visual pathways(3 gliomas,4 meningiomas,3 metastasis,1 stroke) involving either cortical or subcortical visual pathways were investigated by combining fMRI and DTI.fMRI was performed by using flashing checkerboard at 8 Hz.For imaging processing,fMRI analysis was performed with SPM99,and DTI and tractography with DTVⅡ.Fractional anisotropy(FA) of optic radiations and activated volume(VOXELs) of primary visual cortices(V1 and V2) were measured and analyzed at the affected side and the contralateral side.Relative FA(rFA) and relative activated volume(rVOXELs) were also calculated.3D tractography of optic radiations was performed successfully in 11 patients.Results In the patients with brain tumors,FA values in the affected side of optic radiations were significantly different with the contralateral side(P

Tumores hipofisarios: Su repercusión sobre la vía visual / Hypophyseal tumors: Their repercussion on the visual pathway

Los tumores hipofisarios mayores de un centímetro comprimen el quiasma óptico sobre todo si crecen hacia arriba. Con el objetivo de estudiar la repercusión de estas tumoraciones sobre la vía óptica se estudiaron 103 pacientes con un rango de edad entre 15 y 74 años y un franco predominio del sexo femenino. De estos se diagnosticaron 49 pacientes con macroadenomas (47,5 %), 27 con microadenomas (26,2 %), 25 con aracnoidocele (24,3 %), y 2 casos con craneofaringeoma (1,9 %). Las alteraciones del campo visual, detectadas en estos casos por la perimetría cinética y estática computarizadas, son reflejadas en este trabajo. La disminución de la amplitud de los PEV-P en los casos con macroadenoma fue de alta significación estadística (p < 0,031).

The hypophyseal tumors over a cm compress the optical chiasm even more if they grow upwards. 103 patients between 15 and 74 years old and with a clear predominance of females were studied in order to investigate the repercussion of these tumors on the visual pathway. 49 patients were diagnosed macroadenomas (47,5 %), 27 microadenomas (26,2 %), 25 arachnoidels (24,3 %), and 2 craniopharingeoma (1,9 %). The alterations of the visual field detected in these cases by computerized kinetic and static perimetry are included in this paper. The reduction of the extent of the PEV-P in those cases with macroadenoma was of high statistical significance (p <0,003).