1,720,964 research outputs found
Test-retest reliability of motor and cognitive dual task cost in Multiple Sclerosis during various tasks
No full textTest-retest reliability of motor and cognitive dual task cost in Multiple Sclerosis during various tasks
No full textTest-retest reliability of cognitive-motor interference assessments in walking with various task complexities in persons with Multiple Sclerosis
No full textBackground. Simultaneous execution of motor and cognitive tasks can result in worsened performance on one or both tasks, indicating cognitive-motor interference (CMI). A growing amount of research on CMI in persons with multiple sclerosis (pwMS) is observed. However, psychometric properties of dual-task outcomes have been scarcely reported. Objective. To investigate the between-day test-retest reliability of the motor and cognitive dual-task costs (DTCs) during multiple CMI test conditions with various task complexities in pwMS and matched healthy controls (HCs). Methods. A total of 34 pwMS (Expanded Disability Status Scale score 3.0 +/- 0.8) and 31 HCs were tested and retested on 3 single cognitive, 4 single motor, and 12 cognitive-motor dual tasks. Cognitive tasks included serial subtraction by 7, titrated digit span backward, and auditory vigilance. Motor tasks were walking at self-selected speed, over obstacles, crisscross, and while carrying a water-filled cup. Outcome measures were cognitive and motor DTC, calculated as percentage change of dual-task performance compared with single-task performance. Intraclass correlations (ICCs) and Spearman correlation coefficients were calculated as appropriate. Results. For DTCmotor of gait speed, ICCs ranged from 0.45 to 0.81 and Spearman correlations from 0.74 to 0.82. For DTCcognitive, ICCs ranged from -0.18 to 0.49 and Spearman correlations from -0.28 to 0.26. Reliability depended on the type of motor and cognitive task. Conclusion. Reliability of the DTCmotor was, overall, good, whereas that of the DTCcognitive was poor. The "walking" and "cup" dual-task conditions were the most reliable regardless of the integrated cognitive task
Associations between clinical characteristics and dual task performance in Multiple Sclerosis depend on the cognitive and motor dual tasks used.
No full textBackground: In persons with Multiple Sclerosis (pwMS) performing a simultaneous cognitive task while walking often results in slower gait. Clinical characteristics associated with reduced dual task (DT) performance are not yet entirely clear. This multi-centre study aimed to determine the relationship between clinical and demographical characteristics with dual task (DT) walking performance in pwMS during multiple DT conditions. Methods: Nine DT conditions were analysed, consisting of combinations of three types of cognitive ('digit span', 'subtraction', 'vigilance') and three types of walking ('walk', 'walk with cup', 'Ywalk over obstacles') conditions. Primary outcomes were DT gait speed (m/s) and motor DT cost of gait speed (DTCmotor, %). Secondary outcomes were clinical tests of physical and cognitive functioning and patient-reported and demographical outcomes. Firstly, univariate analyses and, subsequently, multivariate analyses with backward modelling, were conducted for each type of walking DT condition separately. Cognitive DT conditions were included in the models as main and as interaction effect with the secondary outcomes. Results: Analysis were performed in 81 pwMS (EDSS 3.3 +/- 1.0). In the final models of DTCmotor, the significant main effects were in 'walk' DT-conditions the Symbol Digit Modalities Test (SDMT), in 'cup' conditions the SDMT and Dynamic Gait Index and in 'obstacles' conditions age. For DT gait speed, main effects were found for the 2-Minute Walking Test (2MWT) and the Multiple Sclerosis Walking Scale for all walking conditions. Additionally, interactions between cognitive DT-conditions and SDMT, age and 2MWT were found. Conclusion: Clinical characteristics related to DT walking performance differed according to cognitive-motor DT-condition used. Still, in general, pwMS with a better mobility demonstrated higher DT gait speed, while a faster information processing speed was related to a lower DTCmotor.The authors thank all the participating persons for their contribution. Further, the authors would like to thank all the participating centers and their staff members that were involved in this study, in particular P. H¨ am¨ alainen, ¨ M. D’hooge and E. Vanzeir
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Differential effects and discriminative validity of motor and cognitive tasks varying in difficulty on cognitive-motor interference in persons with multiple sclerosis
No full textBackground: Cognitive-motor interference (CMI) has been well recognized in persons with multiple sclerosis (pwMS); however, there are limited data on effects of task difficulty.Objective: Examine (1) the effects of motor and cognitive tasks varying in difficulty on the magnitude of CMI and (2) the discriminative validity of CMI between pwMS and healthy controls (HC).Methods: Nine cognitive-motor dual-task (DT) conditions (combinations of three cognitive and three walking tasks) were examined. Outcome measures were DT-performance and dual-task cost (DTC) of gait parameters and correct answers. Task differences and overall group-effects were analysed by mixed model analysis, plus the Wilcoxon signed-rank tests or multivariate analysis of variances (MANOVAs), respectively.Results: Task effects were examined in 82 pwMS (Expanded Disability Status Scale (EDSS): 3.3 +/- 1.0) and discriminative validity in a subsample (35 pwMS and 33 HC). Motor-DTC and DT-performance were affected by difficulty of both the cognitive task (p 0.125). None of the DTCs differed between groups.Conclusion: CMI, and especially motor performance, is affected by difficulty of the DT. Although pwMS performed worse on the tasks than HC, none of the DT-conditions showed a discriminative DTC.Funding
The author(s) disclosed receipt of the following financial support for the research, authorship and/ or publication of this article: This research was funded by the RIMS by Novartis AG, MS Society Flanders, Swedish Promobilia Foundation, and SailingChallenge4MS.
Acknowledgements
The authors thank all the participating persons and all the participating centres and their staff members (A. Romberg, E. Vanzeir, N. De Weerdt, D. De Wilde, P. Hellinckx, N. Shalmoni and others) who were involved in this study
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Full text linkWe 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
- …
