1,720,965 research outputs found
Different CSF protein profiles in amyotrophic lateral sclerosis and frontotemporal dementia with C9orf72 hexanucleotide repeat expansion
No full textObjectives: The hexanucleotide repeat expansion in the C9orf72 gene is the most common mutation associated with amyotrophic lateral sclerosis (C9-ALS) and frontotemporal dementia (C9-FTD). Until now, it is unknown which factors define whether C9orf72 mutation carriers develop ALS or FTD. Our aim was to identify protein biomarker candidates in the cerebrospinal fluid (CSF) which differentiate between C9-ALS and C9-FTD and might be indicative for the outcome of the mutation.Methods: We compared the CSF proteome of 16 C9-ALS and 8 C9-FTD patients and 11 asymptomatic C9orf72 mutation carriers (CAR) by isobaric tags for relative and absolute quantitation. Eleven biomarker candidates were selected from the pool of differentially regulated proteins for further validation by multiple reaction monitoring and single-molecule array in a larger cohort (n=156).Results: In total, 2095 CSF proteins were identified and 236 proteins were significantly different in C9-ALS versus C9-FTD including neurofilament medium polypeptide (NEFM) and chitotriosidase-1 (CHIT1). Eight candidates were successfully validated including significantly increased ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1) levels in C9-ALS compared with C9-FTD and controls and decreased neuronal pentraxin receptor (NPTXR) levels in C9-FTD versus CAR.Conclusions: This study presents a deep proteomic CSF analysis of C9-ALS versus C9-FTD patients. As a proof of concept, we observed higher NEFM and CHIT1 CSF levels in C9-ALS. In addition, we also show clear upregulation of UCHL1 in C9-ALS and downregulation of NPTXR in C9-FTD. Significant differences in UCHL1 CSF levels may explain diverging ubiquitination and autophagy processes and NPTXR levels might reflect different synapses organisation processes
Utility of the repeat and point test for subtyping patients with primary progressive aphasia
No full textBackground: Primary progressive aphasia (PPA) may present with three distinct clinical sybtypes: semantic variant PPA (svPPA), nonfluent/agrammatic variant PPA (nfvPPA), and logopenic variant PPA (lvPPA).Objective: The aim was to examine the utility of the German version of the Repeat and Point (R&P) Test for subtyping patients with PPA.Method: During the R&P Test, the examiner reads out aloud a noun and the participants are asked to repeat the word and subsequently point to the corresponding picture. Data from 204 patients (68 svPPA, 85 nfvPPA, and 51 lvPPA) and 33 healthy controls were analyzed.Results: Controls completed both tasks with >90% accuracy. Patients with svPPA had high scores in repetition (mean=9.2±1.32) but low scores in pointing (mean=6±2.52). In contrast, patients with nfvPPA and lvPPA performed comparably in both tasks with lower scores in repetition (mean=7.4±2.7 for nfvPPA and 8.2±2.34 for lvPPA) but higher scores in pointing (mean=8.9±1.41 for nfvPPA and 8.6±1.62 for lvPPA). The R&P Test had high accuracy discriminating svPPA from nfvPPA (83% accuracy) and lvPPA (79% accuracy). However, there was low accuracy discriminating nfvPPA from lvPPA (Conclusion: The R&P Test helps to differentiate svPPA from 2 nonsemantic variants (nfvPPA and lvPPA). However, additional tests are required for the differentiation of nfvPPA and lvPPA
The applause sign in frontotemporal lobar degeneration and related conditions
No full textThe applause sign, i.e., the inability to execute the same amount of claps as performed by the examiner, was originally reported as a sign specific for progressive supranuclear palsy (PSP). Recent research, however, has provided evidence for the occurrence of the applause sign in various conditions. The aim of this study was to determine the prevalence of the applause sign and correlate its presence with neuropsychological and MRI volumetry findings in frontotemporal lobar degeneration and related conditions. The applause sign was elicited with the three clap test (TCT), with a higher score indicating poorer performance. Data were recorded from 272 patients from the cohort of the German consortium for frontotemporal lobar degeneration (FTLDc): 111 with behavioral variant frontotemporal dementia (bvFTD), 98 with primary progressive aphasia (PPA), 30 with progressive supranuclear palsy Richardson’s syndrome, 17 with corticobasal syndrome (CBS) and 16 with amyotrophic lateral sclerosis with frontotemporal dementia (ALS/FTD). For comparison, 29 healthy elderly control subjects (HC) were enrolled in the study. All subjects underwent detailed language and neuropsychological assessment. In a subset of 156 subjects, atlas-based volumetry was performed. The applause sign occurred in all patient groups (40% in PSP, 29.5% in CBS, 25% in ALS/FTD, 13.3% in PPA and 9.0% in bvFTD) but not in healthy controls. The prevalence was highest in PSP patients. It was significantly more common in PSP as compared to bvFTD, PPA and HC. The comparison between the other groups failed to show a significant difference regarding the occurrence of the applause sign. The applause sign was highly correlated to a number of neuropsychological findings, especially to measures of executive, visuospatial, and language function as well as measures of disease severity. TCT scores showed an inverse correlation with the volume of the ventral diencephalon and the pallidum. Furthermore the volume of the ventral diencephalon and pallidum were significantly smaller in patients displaying the applause sign. Our study confirms the occurrence of the applause sign in bvFTD, PSP and CBS and adds PPA and ALS/FTD to these conditions. Although still suggestive of PSP, clinically it must be interpreted with caution. From the correlation with various cognitive measures we suggest the applause sign to be indicative of disease severity. Furthermore we suggest that the applause sign represents dysfunction of the pallidum and the subthalamic nucleus, structures which are known to play important roles in response inhibition
Utility of the Repeat and Point Test for Subtyping Patients With Primary Progressive Aphasia
No full textRevisiting 'dementia praecox' — Machine learning reveals links between psychosis and behavioral variant frontotemporal dementia
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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