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      Early Corneal Innervation and Trigeminal Alterations in Parkinson Disease : A Pilot Study

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          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          To describe corneal innervation and trigeminal alterations in drug-naive patients with Parkinson disease (PD).

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          Most cited references22

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          Robust determination of the fibre orientation distribution in diffusion MRI: non-negativity constrained super-resolved spherical deconvolution.

          Diffusion-weighted (DW) MR images contain information about the orientation of brain white matter fibres that potentially can be used to study human brain connectivity in vivo using tractography techniques. Currently, the diffusion tensor model is widely used to extract fibre directions from DW-MRI data, but fails in regions containing multiple fibre orientations. The spherical deconvolution technique has recently been proposed to address this limitation. It provides an estimate of the fibre orientation distribution (FOD) by assuming the DW signal measured from any fibre bundle is adequately described by a single response function. However, the deconvolution is ill-conditioned and susceptible to noise contamination. This tends to introduce artefactual negative regions in the FOD, which are clearly physically impossible. In this study, the introduction of a constraint on such negative regions is proposed to improve the conditioning of the spherical deconvolution. This approach is shown to provide FOD estimates that are robust to noise whilst preserving angular resolution. The approach also permits the use of super-resolution, whereby more FOD parameters are estimated than were actually measured, improving the angular resolution of the results. The method provides much better defined fibre orientation estimates, and allows orientations to be resolved that are separated by smaller angles than previously possible. This should allow tractography algorithms to be designed that are able to track reliably through crossing fibre regions.
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            MRtrix: Diffusion tractography in crossing fiber regions

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              Visual and spatial symptoms in Parkinson's disease.

              The interaction of visual/visuospatial and motor symptoms in Parkinson's disease (PD) was investigated by means of a 31-item self-report questionnaire. The majority of 81 non-demented patients reported problems on non-motor tasks that depended on visual or visuospatial abilities. Over a third reported visual hallucinations, double vision and difficulty estimating spatial relations. Freezing of gait was associated with visual hallucinations, double vision and contrast sensitivity deficits. Visual strategies frequently were employed to overcome freezing. The results underscore the importance of investigating visual and visuospatial impairments in PD and their relation to motor symptoms, in order to help patients develop successful compensatory strategies.
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                Author and article information

                Journal
                Cornea
                Cornea
                Ovid Technologies (Wolters Kluwer Health)
                0277-3740
                2018
                April 2018
                : 37
                : 4
                : 448-454
                Article
                10.1097/ICO.0000000000001517
                29373337
                b3f54980-bf20-4926-a2ca-50b6b1117aa0
                © 2018
                History

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