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Acute ON (acute + on)
Selected AbstractsFunctional MRI of the visual cortex and visual testing in patients with previous optic neuritisEUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2002A. R. Langkilde The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed a reduced blood oxygenation level dependent (BOLD) signal increase and a greater asymmetry in the visual cortex, compared with controls. The volume of visual cortical activation was significantly correlated to the result of the contrast sensitivity test. The BOLD signal increase correlated significantly to both the results of the contrast sensitivity test and to the Snellen visual acuity. Our results indicate that fMRI is a useful method for the study of ON, even in cases where the visual acuity is severely impaired. The reduction in activated volume could be explained as a reduced neuronal input; however, the greater asymmetry might point to a cortical reorganization as a consequence of neuronal damage. Future fMRI studies in ON will add to the understanding of the neural adaptive behaviour following ON. [source] Neuroplasticity predicts outcome of optic neuritis independent of tissue damageANNALS OF NEUROLOGY, Issue 1 2010Thomas M. Jenkins MRCP Objectives To determine whether lateral occipital complex (LOC) activation with functional magnetic resonance imaging (fMRI) predicts visual outcome after clinically isolated optic neuritis (ON). To investigate the reasons behind good recovery following ON, despite residual optic nerve demyelination and neuroaxonal damage. Methods Patients with acute ON and healthy volunteers were studied longitudinally over 12 months. Structural MRI, visual evoked potentials (VEPs), and optical coherence tomography (OCT) were used to quantify acute inflammation, demyelination, conduction block, and later to estimate remyelination and neuroaxonal loss over the entire visual pathway. The role of neuroplasticity was investigated using fMRI. Multivariable linear regression analysis was used to study associations between vision, structure, and function. Results Greater baseline fMRI responses in the LOCs were associated with better visual outcome at 12 months. This was evident on stimulation of either eye (p = 0.007 affected; p = 0.020 fellow eye), and was independent of measures of demyelination and neuroaxonal loss. A negative fMRI response in the LOCs at baseline was associated with a relatively worse visual outcome. No acute electrophysiological or structural measures, in the anterior or posterior visual pathways, were associated with visual outcome. Interpretation Early neuroplasticity in higher visual areas appears to be an important determinant of recovery from ON, independent of tissue damage in the anterior or posterior visual pathway, including neuroaxonal loss (as measured by MRI, VEP, and OCT) and demyelination (as measured by VEP). ANN NEUROL 2010;67:99,113 [source] Colour Doppler imaging evaluation of blood flow parameters in the ophthalmic artery in acute and chronic phases of optic neuritis in multiple sclerosisACTA OPHTHALMOLOGICA, Issue 1 2009Pavel Hradílek Abstract. Purpose:, Optic neuritis (ON) is a common manifestation of multiple sclerosis (MS). It is caused by the immune-mediated inflammation of the optic nerve. Some vascular factors that may influence blood flow in the ophthalmic artery (OA) have also been suggested as factors in the pathogenesis of ON. The purpose of our study was to evaluate blood flow velocities and resistance (RI) and pulsatile (PI) indices in the OA in both orbits in patients in the acute and chronic phases of unilateral ON and to compare these with equivalent findings in healthy control subjects. Methods:, Orbital colour Doppler imaging (CDI) was performed in 40 consecutive MS patients during acute unilateral ON prior to corticosteroid treatment. Optic neuritis was diagnosed on the basis of clinical presentation and facultative assessment of visual evoked potentials (VEPs). The peak systolic (PSV) and end-diastolic (EDV) velocities and RI and PI were measured in the OA in both eyes. We compared results from affected and unaffected orbits using the paired t -test. The same measurements were performed in 114 MS patients with a history of acute unilateral ON that occurred > 1 year prior to ultrasound examination. We also measured the same parameters in the middle cerebral arteries (MCAs) on both sides in all subjects in both groups. The same measurements were obtained in healthy controls. Results:, The PSV (p < 0.0001), RI (p < 0.0001) and PI (p < 0.0001) in the OA in the eye affected with acute ON were significantly higher than in the unaffected eye. There was no difference in EDV in the OA between affected and unaffected eyes (p > 0.05) in the group with acute ON. We did not observe any significant differences between eyes in either blood flow velocities or the RI or PI (p > 0.05) in the group in the chronic phase of ON or in the control group. All the parameters in the MCAs on both sides were normal in both the acute and chronic groups, as well as in the control group. Conclusions:, Pathophysiological changes during acute unilateral ON influence orbital haemodynamics, as is indicated by increased PSV, RI and PI in the OA in eyes affected with ON. However, these changes do not persist over longer periods. [source] Optic neuritis and multiple sclerosisACTA OPHTHALMOLOGICA, Issue 3 2001Mats Söderström ABSTRACT. Purpose: Review of the association between optic neuritis (ON) and multiple sclerosis (MS). Results: MS often presents as acute unilateral ON. While it is clear that many patients with ON suffer from a generalized disease of the central nervous system that will go on to clinically definite MS (CDMS), it is also clear that others do not. With more and more well-informed patients and the emerging pharmacotheraphy for MS, the distinction between those patients with ON who have MS and those who do not, has become more important than ever before. Recently, a large randomized clinical trial on patients with ON or other clinically isolated syndromes suggestive of MS and evidence of prior subclinical demyelination on magnetic resonance imaging of the brain, found that treatment with recombinant interferon-beta-1a is beneficial by reducing the development of CDMS. Conclusion: Ophthalmologists should refer their patients with acute ON to a neurologist for MS-directed investigations and decisions regarding early institution of disease modifying therapy. [source] | ||||||||||