1,720,982 research outputs found
Advanced technologies for axial impairment in Parkinson's disease: from early detection to outcome prediction
Full text linkAxial motor symptoms—such as balance, gait, posture, and speech disorders—mark a critical milestone in the progression of Parkinson's disease (PD), significantly affecting patients’ prognosis and quality of life. However, the long-term evolution of these symptoms, especially in patients undergoing advanced therapies like subthalamic nucleus deep brain stimulation (STN-DBS), remains poorly understood. Also, current clinical evaluations lack sensitivity in detecting axial disorders at their early stages, and reliable predictors for patients at increased risk of developing these symptoms are still largely unknown. Recent technological advances in invasive neuromodulation (e.g., DBS), wearable sensors, and artificial intelligence-based computational methods provide new opportunities to address these challenges. This Thesis presents the main scientific findings from the PhD program, centred on the clinical and instrumental evaluation of axial impairment in PD using advanced technologies. The first section of the Thesis examines the short- and long-term clinical progression of axial disorders in a cohort of advanced PD patients treated with STN-DBS. Through a retrospective longitudinal analysis, a gradual worsening of axial symptoms, along with complications such as falls, was demonstrated over a period of up to 15 years post-surgery. The second section explores the use of wearable inertial and electromyographic sensors to assess gait and balance disorders in laboratory and home settings. These technologies accurately captured patient movement and quantified axial disturbances, highlighting their potential for telemedicine applications. Additionally, artificial intelligence algorithms were applied to automatically analyse speech in STN-DBS patients, revealing the impact of this therapy on vocal functions. In the third section, longitudinal regression analyses of a large PD cohort identified specific clinical predictors of axial symptoms, offering insight into patients at higher risk of developing related complications. A single wearable sensor was also used to accurately predict gait and balance impairments, demonstrating its utility for enhancing remote clinical assessments. In conclusion, the present Thesis underscores the potential of innovative monitoring and management strategies that leverage advanced technologies to improve clinical practice in PD
Embedded wearable integrating real-time processing of electromyography signals
No full textWe realized a non-invasive wearable device able to record muscle activity using patch electrodes positioned on the skin over the muscle. It is an integrated system-on-board developed for the detection of several physical and physiologic human parameters which includes specific circuits for detecting the surface electromyography signal and algorithms for the real-time data processing optimized to low computational load. In real time, the proposed system dissipates only 26 mW and guarantees 20 h battery autonomy. The system exhibits performance comparable with those achieved with state-of-art wired equipment used in the hospitals, but with the advantage of being an embedded wearable wireless device
Rigidity in Parkinson's disease: Evidence from biomechanical and neurophysiological measures
No full text: Although rigidity is a cardinal motor sign in patients with Parkinson's disease (PD), the instrumental measurement of this clinical phenomenon is largely lacking, and its pathophysiological underpinning remains still unclear. Further advances in the field would require innovative methodological approaches able to measure parkinsonian rigidity objectively, discriminate the different biomechanical sources of muscle tone (neural or visco-elastic components), and finally clarify the contribution to objective rigidity exerted by neurophysiological responses which have been previously associated with this clinical sign (i.e., the long-latency stretch-induced reflex). Twenty patients with PD (67.3 ± 6.9 years) and 25 age- and sex-matched controls (66.9 ± 7.4 years) were recruited. Rigidity was measured clinically and through a robotic device. Participants underwent robot-assisted wrist extensions at 7 different angular velocities randomly applied, when ON therapy. For each value of angular velocity, several biomechanical (i.e., elastic, viscous and neural components) and neurophysiologic measures (i.e., short- and long-latency reflex and shortening reaction) were synchronously assessed and correlated with the clinical score of rigidity (i.e., Unified Parkinson's Disease Rating Scale - part III subitems for the upper limb). The biomechanical investigation allowed us to measure objective rigidity in PD and estimate the neuronal source of this phenomenon. In patients, objective rigidity progressively increased along with the rise of angular velocities during robot-assisted wrist extensions. The neurophysiological examination disclosed increased long-latency reflexes, but not short-latency reflexes nor shortening reaction, in PD compared with controls. Long-latency reflexes progressively increased according to angular velocities only in patients with PD. Lastly, specific biomechanical and neurophysiological abnormalities correlated with the clinical score of rigidity. Objective rigidity in PD correlates with velocity-dependent abnormal neuronal activity. The observations overall (i.e., the velocity-dependent feature of biomechanical and neurophysiological measures of objective rigidity) would point to a putative subcortical network responsible for objective rigidity in PD which requires further investigation
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
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
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