1. Articles in category: Neurology

    1-24 of 343 1 2 3 4 ... 13 14 15 »
    1. Optical coherence tomography and visual evoked potentials combined use as monitoring tools in Multiple Sclerosis patients

      Optical coherence tomography and visual evoked potentials combined use as monitoring tools in Multiple Sclerosis patients

      In Multiple Sclerosis-MS, optical coherence tomography-OCT is used to measure retinal nerve fiber layer-RNFL thickness as a marker of axonal loss and visual evoked potentials-VEPs as an indicator of demyelination. However, no clear indications are available on their combined use in MS monitoring. 80 MS patients underwent neurological and neurophysiological evaluation with OCT and VEPs, with routine clinical and MRI monitoring for a mean period of 1 year. Additional OCT-VEPs follow-up was obtained in 50 patients. Comparing eyes with and without previous ON, VEP latency and RNFL thickness were respectively significantly higher (131.2 ms Vs 118.8 ms, p ...

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    2. Optical Coherence Tomography to Assess Neurodegeneration in Multiple Sclerosis (Book Chapter)

      Optical Coherence Tomography to Assess Neurodegeneration in Multiple Sclerosis (Book Chapter)

      Retinal spectral domain optical coherence tomography (OCT) has emerged as a clinical and research tool in multiple sclerosis (MS) and optic neuritis (ON). This chapter summarizes a short OCT protocol as included in international consensus guidelines. The protocol was written for hands-on style such that both clinicians and OCT technicians can make use of it. The protocol is suitable for imaging of the optic nerve head and macular regions as a baseline for follow-up investigations, individual layer segmentation, and diagnostic assessment.

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    3. Examining multiple sclerosis through the eyes of a child

      Examining multiple sclerosis through the eyes of a child

      etinal ganglion cells (RGCs) receive input from photoreceptive cells, have unmyelinated axons that constitute the retinal nerve fiber layer (RNFL), and gain myelin as they pass through the lamina cribrosa to form the optic nerve. RGC axons project to several structures within the CNS, including the lateral geniculate nucleus of the thalamus. The ganglion cell layer (GCL) constitutes a readily quantifiable layer of neuronal cell bodies. Whereas research methods of cortical neuronal quantification in multiple sclerosis (MS) continue to evolve, the advent of high-resolution optical coherence tomography (OCT) images, derived from software that segments discrete retinal layers, has enabled quantification ...

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    4. Association of Cognitive deficits with Optical Coherence Tomography changes in Multiple Sclerosis Patients

      Association of Cognitive deficits with Optical Coherence Tomography changes in Multiple Sclerosis Patients

      Background: Multiple Sclerosis (MS) is a neurodegenerative disorder affecting myelinated axons. Cognitive impairments have been observed in patients with MS. Although there are some methods to examine the progress of MS, a tool hasn’t been developed to fully correlate MS symptoms with cognitive deficits. Methods: Among patients referring to Kerman-Iran Shafa Hospital, 60 MS patients were chosen to be included in the study. Their demographic data was obtained and patients filled the Brief International Cognitive Assessment for MS (BICAMS) questionnaire and then underwent OCT. The Chi-square test was used to analyze the frequency of patients with normal and abnormal ...

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    5. Evaluation of Retinal Nerve Fiber Layer in Patients with Idiopathic Optic Perineuritis using Optical Coherence Tomography

      Evaluation of Retinal Nerve Fiber Layer in Patients with Idiopathic Optic Perineuritis using Optical Coherence Tomography

      The aim of this study was to assess the effect of idiopathic Optic perineuritis on the retinal nerve fiber layer, and determine the ability of optical coherence tomography to evaluate retinal nerve fiber loss after idiopathic Optic perineuritis. Four patients were assessed in this study. In all cases, average retinal nerve fiber layer was significantly thinner in the affected eye in comparison with the normal reference value and with the value for the contralateral normal eye at 12 months after the onset of optic perineuritis. Our study revealed that retinal nerve fiber layer loss occurs in idiopathic optic nerve sheath ...

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    6. Retinal Ganglion Cell Analysis Using High-Definition Optical Coherence Tomography in Patients with Mild Cognitive Impairment and Alzheimer's Disease

      Retinal Ganglion Cell Analysis Using High-Definition Optical Coherence Tomography in Patients with Mild Cognitive Impairment and Alzheimer's Disease

      Background: Alzheimer's disease (AD) is a neurodegenerative disorder with emerging evidence that it is associated with retinal ganglion cell loss; however, few data exist to establish this association. Objective: To determine whether macular ganglion cell -inner plexiform layer (GC-IPL) and retinal nerve fiber layer (RNFL), as quantitatively measured by non-invasive in vivo spectral-domain optical coherence tomography (SD-OCT), are altered in patients with AD and mild cognitive impairment (MCI). Methods: Patients with AD and MCI were recruited from dementia/memory clinics, and cognitively normal controls were selected from the Singapore Epidemiology of Eye Disease program. SD-OCT (CIRRUS, software version 6 ...

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    7. Optical coherence tomography and its use in optical neuritis and multiple sclerosis

      Optical coherence tomography and its use in optical neuritis and multiple sclerosis

      Optical coherence tomography is a relatively new non-invasive imaging technique used for obtaining the images and quantifying the layers of the retina. It also provides information about optic nerve head topography, peripapillary retinal nerve fiber layer thickness, and macular volume which correlates with axonal loss. Until now, this method was used mainly in ophthalmology; now it has emerged as relevant in neurology as well. RNFL thickness is of particular interest in optic neuropathies and in multiple sclerosis. In sclerosis multiplex, axonal loss occurs as early as the first stages and the quantification of the RNFL thickness by OCT provides an ...

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    8. Applications of visual evoked potentials and Fourier-domain optical coherence tomography in Parkinson's disease: a controlled study

      Applications of visual evoked potentials and Fourier-domain optical coherence tomography in Parkinson's disease: a controlled study

      Purpose: The goal of this cross-sectional observational study was to quantify the pattern-shift visual evoked potentials (VEP) and the thickness as well as the volume of retinal layers using optical coherence tomography (OCT) across a cohort of Parkinson's disease (PD) patients and age-matched controls. Methods: Forty-three PD patients and 38 controls were enrolled. All participants underwent a detailed neurological and ophthalmologic evaluation. Idiopathic PD cases were included. Cases with glaucoma or increased intra-ocular pressure were excluded. Patients were assessed by VEP and high-resolution Fourier-domain OCT, which quantified the inner and outer thicknesses of the retinal layers. VEP latencies and ...

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    9. Multi-contrast optical coherence tomography for brain imaging and mapping (Thesis)

      Multi-contrast optical coherence tomography for brain imaging and mapping (Thesis)

      Although our knowledge of neuronal function and regional activity has been tremendously enriched in the past decades, coordination of these neurons to form the complex behaviors has yet to be understood. The neuronal pathways (also named connectome) form the structural foundation of the dynamic circuits in the brain. The recent interests in connectome and brainwide database have imposed a pressing need for high-resolution imaging techniques that allows large coverage. This dissertation develops a novel multi-contrast optical coherence tomography (MC-OCT) technique for the application of brainwide imaging and architectural mapping in 3D at high spatiotemporal resolution, with an emphasis on the ...

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    10. Monitoring of Cerebral Hemodynamics Post Optogenetic Stimulation via Optical Coherence Tomography

      Monitoring of Cerebral Hemodynamics Post Optogenetic Stimulation via Optical Coherence Tomography

      In this article Spectral Domain Optical Coherence Tomography is used to measure the hemodynamic response induced by optogenetic stimulation in the somatosensory cortex of transgenic mice. By analyzing the 3D angiograms and Doppler measurements produced by coherence tomography, we observed significant increase in blood flow as a result of increased vessel diameter and blood velocity following optical stimulation of cortical neurons. Such distinct responses were not observed in control experiments where the brain of wildtype mice were exposed to the same light pulses.

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    11. Graphene Sensors Stimulate Neurons Optically And Electronically

      Graphene Sensors Stimulate Neurons Optically And Electronically

      While electrical sensing is a mainstay of neurological studies, optical methods have recently started to become more prevalent. A new sensor system from DARPA now allows both modalities to be used together, for greater insights into neural structure and function. Electrical impulses are the primary way that neural cells communicate. Historically, electrical studies have enabled the evaluation of neural cell communication. Generally, the understanding of neural cells that was gained by studying electrical impulses was garnered through correlation studies, so a direct link was not possible to prove relationships between neural cell electrical activity and behavior. Recently, the development of ...

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    12. Automated 3D Segmentation of Intraretinal Surfaces in SD-OCT Volumes in Normal and Diabetic Mice

      Automated 3D Segmentation of Intraretinal Surfaces in SD-OCT Volumes in Normal and Diabetic Mice

      Purpose: To describe an adaptation of an existing graph-theoretic method (initially developed for human optical coherence tomography [ OCT ] images) for the three-dimensional ( 3D ) automated segmentation of 10 intraretinal surfaces in mice scans, and assess the accuracy of the method and the reproducibility of thickness measurements. Methods: Ten intraretinal surfaces were segmented in repeat spectral domain ( SD )- OCT volumetric images acquired from normal ( n = 8) and diabetic ( n = 10) mice . The accuracy of the method was assessed by computing the border position errors of the automated segmentation with respect to manual tracings obtained from two experts. The reproducibility was statistically assessed ...

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    13. Retinal neurodegeneration on optical coherence tomography and cerebral atrophy

      Retinal neurodegeneration on optical coherence tomography and cerebral atrophy

      Neurodegeneration in dementia is mainly evaluated by assessing cerebral atrophy, while retinal neurodegeneration can be quantified in vivo using optical coherence tomography (OCT). We examined the association of retinal nerve fibre layer (RNFL) and ganglion cell-inner plexiform layer (GC–IPL) thinning with global and regional cerebral atrophy on magnetic resonance imaging (MRI). Malay participants aged 60–80 years from the Epidemiology of Dementia in Singapore Study underwent comprehensive examinations, including 3-Tesla cranial MRI. RNFL and GC-IPL thicknesses were obtained from spectral domain-OCT; and cerebral grey and white matter volumes were obtained from MRI scans using a validated segmentation tool. Linear ...

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    14. Re: Garcia-Martin et al.: Retinal layer segmentation in patients with multiple sclerosis using spectral domain optical coherence tomography

      Re: Garcia-Martin et al.: Retinal layer segmentation in patients with multiple sclerosis using spectral domain optical coherence tomography

      With great interest we read the article by Garcia-Martin et al.1 The authors were able to include an impressively large number of patients and this dataset provides an excellent opportunity to evaluate retinal layer affection in multiple sclerosis. However, after carefully reading the article, we are concerned that there are discrepancies in the document that require clarification.

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    15. Optical Coherence Tomography (OCT) – A New Diagnostic Tool in Psychiatry?

      Optical Coherence Tomography (OCT) – A New Diagnostic Tool in Psychiatry?

      Optical coherence tomography (OCT) is a non-invasive, contact-less imaging method which provides an “in vivo” representation of the retina. It allows the quantitative measurement of retinal nerve fibre layer thickness (RNFLT) and macula thickness (MT) and, in addition, is suitable to measure volumes (e. g., macula volume/MV). In the research of neurodegenerative diseases, OCT has been increasingly used and has shown its potential as a possible diagnostic tool over the course of the last few years. In recent years, the hypothesis that mental disorders like schizophrenia or unipolar depressive disorder have a degenerative component was established through a variety ...

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    16. Comparative Diagnostic Accuracy of Ganglion Cell-Inner Plexiform and Retinal Nerve Fiber Layer Thickness Measures by Cirrus and Spectralis Optical Coherence Tomography in Relapsing-Remitting Multiple Sclerosis

      Comparative Diagnostic Accuracy of Ganglion Cell-Inner Plexiform and Retinal Nerve Fiber Layer Thickness Measures by Cirrus and Spectralis Optical Coherence Tomography in Relapsing-Remitting Multiple Sclerosis

      Objective . To estimate sensitivity and specificity of several optical coherence tomography (OCT) measurements for detecting retinal thickness changes in patients with relapsing-remitting multiple sclerosis (RRMS), such as macular ganglion cell-inner plexiform layer (GCIPL) thickness measured with Cirrus (OCT) and peripapillary retinal nerve fiber layer (pRNFL) thickness measured with Cirrus and Spectralis OCT. Methods . Seventy patients (140 eyes) with RRMS and seventy matched healthy subjects underwent pRNFL and GCIPL thickness analysis using Cirrus OCT and pRNFL using Spectralis OCT. A prospective, cross-sectional evaluation of sensitivities and specificities was performed using latent class analysis due to the absence of a gold standard ...

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    17. Homonymous Ganglion Cell Layer Thinning After Isolated Occipital Lesion: Macular OCT Demonstrates Transsynaptic Retrograde Retinal Degeneration

      Homonymous Ganglion Cell Layer Thinning After Isolated Occipital Lesion: Macular OCT Demonstrates Transsynaptic Retrograde Retinal Degeneration

      A 48-year-old man was examined 24 months after medial and surgical treatment of an isolated well-circumscribed right occipital lobe abscess. An asymptomatic residual left homonymous inferior scotoma was present. Fundus examination revealed temporal pallor of both optic discs, and optical coherence tomography (OCT) revealed mild temporal loss of retinal nerve fiber layer in both eyes. No relative afferent pupillary defect was present. Assessment of the retinal ganglion cell layer demonstrated homonymous thinning in a pattern corresponding to the homonymous visual field loss. There were no abnormalities of the lateral geniculate nuclei or optic tracts on review of the initial brain ...

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      Mentions: Randy H. Kardon
    18. Macular Volume Loss In Huntington’s Disease On Optical Coherence Tomography- A Pilot Biomarker Study

      Macular Volume Loss In Huntington’s Disease On Optical Coherence Tomography- A Pilot Biomarker Study

      Background Optical coherence tomography (OCT) is a novel, non-ionising, retinal nerve fibre layer (RNFL) imaging modality with rapid, consistent data acquisition and a much shorter scan time versus MRI. In Alzheimer’s disease, Parkinson’s disease and multiple sclerosis, RNFL loss is proposed as a surrogate marker of brain neuronal loss. In related polyglutamine disorders, Spinocerebellar Ataxia 7 (SCA 7), retinal degeneration is well established clinically. In a recent OCT study of 9 Spinocerebellar Ataxia 1 (SCA1) patients, significant RNFL loss versus controls was seen. In Huntington’s disease, drosophila models show photoreceptor degeneration, while both R6/1 and R6 ...

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    19. University of Texas at Arlington Receives NIH Grant to Study All Optical Control and Monitoring of Neural Activity.

      University of Texas at Arlington Receives NIH Grant to Study All Optical Control and Monitoring of Neural Activity.

      University of Texas at Arlington Received at 2014 NIH Grant for $206,065 to Study All Optical Control and Monitoring of Neural Activity. The principal investigator is Samarendra Mohanty. The program began in 2014 and ends in 2015. Below is a summary of the propose work. Success of optogenetic intervention of neural activity requires optimization of delivery of genes encoding light sensitive proteins (opsins) to specific cells, and to record the changes in cells and tissue during optogenetic stimulation. The most-commonly used method for delivering opsin(s) is use of viral vector, which is prone to cause unexpected inflammatory responses ...

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    20. Feature Of The Week 9/14/14: UC Davis Investigates Brain Imaging with Optical Coherence Tomography

      Feature Of The Week 9/14/14: UC Davis Investigates Brain Imaging with Optical Coherence Tomography

      One of the nine high priority research areas in the recent BRAIN Initiative (executive summary available at HERE ) is to “Delineate mechanisms underlying human brain imaging technologies.” While empowering tools such as two-photon microscopy, used in conjunction with dyes and indicators, can image cellular and vascular activity, even measuring activity in all cells and vessels comprising a single voxel in a functional magnetic resonance imaging (fMRI) scanner remains a daunting task. Hence, mesoscopic imaging tools are needed to help bridge the gap between microscopic and macroscopic (human brain level) findings. Here, using Optical Coherence Tomography angiography at 1300 nm, we ...

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    21. Optical coherence tomography appears valuable for tracking MS patients over time

      Optical coherence tomography appears valuable for tracking MS patients over time

      Retinal changes over time mirror global central nervous system processes in patients with multiple sclerosis, according to findings from a longitudinal study comparing optical coherence tomography and magnetic resonance imaging findings. The results validate optical coherence tomography (OCT) measures for both clinical monitoring of patients, and as an outcome measure in clinical trials, and could have implications that reach beyond MS, Dr. Shiv Saidha said at the joint meeting of the European and Americas committees for Treatment and Research in Multiple Sclerosis. In 107 multiple sclerosis (MS) patients with a mean age of 44 years and median disease duration of ...

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    22. Ultrasensitive detection of 3D cerebral microvascular network dynamics in vivo

      Ultrasensitive detection of 3D cerebral microvascular network dynamics in vivo

      Despite widespread applications of multiphoton microscopy in microcirculation, its small field of view and inability to instantaneously quantify cerebral blood flow velocity (CBFv) in vascular networks limit its utility in investigating the heterogeneous responses to brain stimulations. Optical Doppler tomography (ODT) provides 3D images of CBFv networks, but it suffers poor sensitivity for measuring capillary flows. Here we report on a new method, contrast-enhanced ODT with Intralipid that significantly improves quantitative CBFv imaging of capillary networks by obviating the errors from long latency between flowing red blood cells (low hematocrit ~ 20% in capillaries). This enhanced sensitivity allowed us to measure ...

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    23. Decreased light attenuation in cerebral cortex during cerebral edema detected using optical coherence tomography

      Decreased light attenuation in cerebral cortex during cerebral edema detected using optical coherence tomography

      Cerebral edema develops in response to a variety of conditions, including traumatic brain injury and stroke, and contributes to the poor prognosis associated with these injuries. This study examines the use of optical coherence tomography (OCT) for detecting cerebral edema in vivo . Three-dimensional imaging of an in vivo water intoxication model in mice was performed using a spectral-domain OCT system centered at 1300 nm. The change in attenuation coefficient was calculated and cerebral blood flow was analyzed using Doppler OCT techniques. We found that the average attenuation coefficient in the cerebral cortex decreased over time as edema progressed. The initial ...

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    1-24 of 343 1 2 3 4 ... 13 14 15 »
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