1,721,012 research outputs found

    Diagnostic difficulties with central nervous system actinomycosis

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    When faced with expanding brain lesions of unknown origin showing a ring-shaped enhancement on post-contrast imaging, we use definite criteria to direct further investigation and distinguish among a number of possible diagnostic hypotheses. However, a correct diagnosis may be difficult in some cases, especially when dealing with less frequent conditions. This is the case of actinomycosis, a highly treatable but insidious infection for which nowadays there may be a low level of attention. Brain localization is associated with a significant morbidity and may represent a true diagnostic pitfall. Here we report the difficulties encountered with a case of central nervous system actinomycosis

    Topographical disorientation consequent to amnesia of spatial location in a patient with right parahippocampal damage.

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    We describe a patient who selectively lost the ability to orient himself in the environment after a stroke involving the right parahippocampal gyrus. The neuropsychological assessment showed a specific pattern of impairment of topographical memory; the patient recognised and recalled environmental landmarks but was unable to recall their spatial location. This study provides evidence that different forms of topographical disorientation may be related to distinct mechanisms of cognitive dysfunction. Furthermore, neuroimaging data suggest that a lesion of the right parahippocampal gyrus is critically related to pure topographical disorientation

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed

    Multiple sclerosis, solitary sclerosis or something else?

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    BACKGROUND: Inflammatory demyelinating diseases of the central nervous system represent a wide spectrum of entities and their classification cannot currently be regarded complete. OBJECTIVE: Our aim is to describe a series of patients presenting with progressive myelopathy associated to a single demyelinating lesion of the spinal cord. METHODS: We identified the patients affected by chronic progressive spinal cord dysfunction related to a single spinal cord lesion not satisfying the diagnostic criteria for any of the currently defined diseases. RESULTS: Seven females and one male were included. The median age at onset of symptoms was 53 years (range 42-68) and the median follow-up was 8 years (range 5-12). Brain and spinal magnetic resonance imaging (MRI) scans detected only one single, circumscribed, T2 hyperintense, non-longitudinally extensive lesion at level of cervico-medullary junction or cervical cord, in the absence of Gadolinium enhancement or swelling. Cerebrospinal fluid (CSF) examination displayed neither oligoclonal bands nor raised IgG index. A response to immunosuppressive agents was observed in some of the patients. Serial control brain and spinal MRI did not reveal accumulation of new lesions. CONCLUSION: New entities or variants should be included among the inflammatory demyelinating diseases of the central nervous system, and their characterization may have relevant prognostic and treatment implications
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