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Correlati corticali della paratonia in pazienti con malattia di Alzheimer
No full textLa paratonia è caratterizzata dall’incapacità di mantenere la muscolatura degli arti rilassata durante la mobilizzazione passiva. Sono stati descritti due tipi di paratonia: facilitatoria, quando il soggetto assiste, e oppositiva, quando il soggetto si oppone involontariamente al movimento imposto dall’esaminatore. Tipicamente correlata a decadimento cognitivo, e valutata mediante scale cliniche, recenti studi hanno dimostrato la possibilità di valutare quantitativamente la paratonia mediante elettromografia di superficie. La sensibilità della metodica ha permesso di dimostrare la presenza di paratonia anche in soggetti sani e giovani o comunque in soggetti in cui la valutazione clinica non è in grado di evidenziarla. La prevalenza e l’entità della paratonia aumenta con l’età ed è maggiore in soggetti con decadimento cognitivo, in particolare quando sono coinvolte le aree frontali, tuttavia i meccanismi fisiopatologici alla base della paratonia non sono ancora stati chiariti. L’obiettivo di questo studio è verificare se in pazienti con malattia di Alzheimer sia presente una correlazione inversa tra paratonia e funzione delle aree premotorie, che potrebbero esercitare un controllo inibitorio sul circuito sensori-motorio corticale, ipoteticamente alla base della paratonia.
Un gruppo di pazienti con malattia di Alzheimer dimostrato dall’accumulo di beta-amiloide all’esame PET è stato valutato mediante elettromiografia di superficie a livello dei muscoli bicipite e tricipite dell’arto superiore non dominante durante l’esecuzione di movimenti passivi di flesso-estensione. L’attività paratonica registrata è stata correlata alla funzione delle aree premotorie sfruttando le sequenze di perfusione effettuate all’inizio della valutazione PET-amiloide.
I risultati mostrano una significativa correlazione inversa tra il livello di paratonia ed il metabolismo cerebrale nelle aree premotorie, in particolare nelle aree di Brodmann 6, 8 e 9 (p < 0.006). In pazienti con malattia di Alzheimer, una ridotta funzione delle aree premotorie corrisponde a più alti livelli di paratonia, confermando quindi l’ipotesi alla base dello studio. Bassi livelli di paratonia sono verosimilmente fisiologici e dovuti all’attivazione delle aree motorie primarie ad opera delle afferenze sensitive ad origine fusoriale attivate dal movimento passivo. L’aumento dell’attività paratonia sarebbe quindi spiegabile da una disfunzione delle aree premotorie e quindi dal ridursi dell’attività inibitoria sull’area motoria primaria. Questo studio è il primo a chiarire i meccanismi fisiopatologici della paratonia e a valorizzarne l’utilità come biomarcatore di funzione corticale premotoria.Paratonia is a form of hypertonia that occurs during the passive movement of a limb by an operator. Two types of paratonia can be recognized (facilitatory and oppositional), and it can be elicited in subjects of all ages with a higher incidence in elderly subjects and those with a form of dementia, especially with frontal lobe degeneration. Previous electromyography-based studies have allowed the evaluation of paratonia with quantitative data. The aim of this study is to verify a possible inverse correlation between paratonic activity and premotor area function in subjects with Alzheimer's disease by cross-referencing electromyographic data with PET amyloid data.
The results obtained show a significant inverse correlation between the level of paratonia and cerebral metabolism in premotor areas, particularly in Brodmann areas 6, 8, and 9 (p < 0.006). Considering that the separate analysis of the two types of paratonia does not reach significance, we can hypothesize that oppositional and facilitatory paratonia are the different manifestations of a frontal lobe dysfunction that results in an inability to relax the muscles. We can also hypothesize that there is a cortical control circuit that premotor areas play on the primary motor area
The role of physical activity against chemotherapy-induced peripheral neuropathy: a narrative review
No full textSeveral studies investigated the side effect of adjuvant cancer treatments, and different types of preventive techniques or treatments have been assessed. Chemotherapy-induced peripheral neuropathy (CIPN) is the most common neurological side effect. Exercise training has been widely studied as an adjuvant therapy to prevent CIPN and improve post-chemotherapy functional outcome and quality of life (QoL). This narrative review aims to summarize the data obtained from the latest studies about physical activity (PA) for the prevention and treatment of CIPN and associated QoL measures. Literature research was conducted to obtain studies including PA interventions for patients with CIPN. Ten studies met inclusion criteria and were therefore summarized and discussed, focusing on exercise type and functional outcome. It seems clear that, regardless of the type of exercise, PA plays a positive role in the treatment of CIPN, providing a significant symptom improvement. There has been no standardization of type, quantity, and intensity of PA administered to the subjects in the various studies probably due to a physiological difference between samples, grade of neuropathy, and difference among therapies
Surface Electromyography Spectral Parameters for the Study of Muscle Fatigue in Swimming
No full textThe purpose of this study was to assess validity, stability and sensitivity, of 4 spectral parameters–median frequency (Fmed), mean frequency (Fmean), Dimitrov index (DI), and mean instant frequency (Fmi)–in measuring localized muscle fatigue in swimming and to investigate their correlation with the variations of kinematic data and mechanical fatigue. Electrophysiological measures of muscle fatigue were obtained in real-time during a 100 m front crawl test at maximum speed in 15 experienced swimmers, using surface electromyography in six muscles employed in front crawl, while kinematic data of swimming was measured from video analysis. Mechanical fatigue was measured as the difference between muscle strength prior to and immediately after the 100 m front crawl in a dry-land multi-stage isometric contraction test. Statistically significant fatigue (p < 0.0001) was found for all spectral parameters in all muscles. Fmed and Fmean varied between 10 and 25%, DI between 50 and 150%, and Fmi between 5 and 10%. Strong correlation (Pearson r ≥ 0.5) with mechanical fatigue was found for all spectral parameters except for Fmi and it was strongest for Fmed and Fmean. From our study, it turns out that Fmed and Fmean are more valid and stable parameters to measure fatigue in swimming, while DI is more sensitive
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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