Quantifying Muscle Fatigue of the Low Back during Repetitive Load Lifting Using Lyapunov Analysis

Background: Occupational low back disorders are often associated with exposure to work-related physical risk factors such as muscle fatigue in the low back.Objective: The objective of this study was to investigate the possible relationship between the divergence of the kinematic trajectories of the low back system and the different stages of fatigue during the execution of a repetitive lifting task.Methods: The patterns of the low back system were recorded using markers on specific vertebras during the repetitive load lifting from the floor to a 0.75 m height table. The maximum Lyapunov exponent, λmax of the recorded patterns was calculated from the x and y coordinates of the lower back markers using the algorithm proposed by Wolf.Results: The results of the λmax values determined three different sections of muscle fatigue which were also in agreement with the Borg’s clinical scale of perceived fatigue results. The assessment of the λmax values between the three different sections showed a descriptive point where the muscle fatigue accumulation may have resulted in a change of the low back control.Conclusion: Lyapunov exponent methodology could be a reliable methodology for ergonomists to provide an index to design the work/rest ratio ergonomically

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Prediction of second neurological attack in patients with clinically isolated syndrome using support vector machines

The aim of this study is to predict the conversion from clinically isolated syndrome to clinically definite multiple sclerosis using support vector machines. The two groups of converters and non-converters are classified using features that were calculated from baseline data of 73 patients. The data consists of standard magnetic resonance images, binary lesion masks, and clinical and demographic information. 15 features were calculated and all combinations of them were iteratively tested for their predictive capacity using polynomial kernels and radial basis functions with leave-one-out cross-validation. The accuracy of this prediction is up to 86.4% with a sensitivity and specificity in the same range indicating that this is a feasible approach for the prediction of a second clinical attack in patients with clinically isolated syndromes, and that the chosen features are appropriate. The two features gender and location of onset lesions have been used in all feature combinations leading to a high accuracy suggesting that they are highly predictive. However, it is necessary to add supporting features to maximise the accuracy. © 2013 IEEE

Evaluation of muscle fatigue accumulation in the low back and the upper limbs during the execution of a repetitive task

The Eurostat studies conducted from 1995, with the aim to record the occurrence of occupational diseases in EU workplaces, have shown that the musculoskeletal disorders (MSDs) are referred to the three most common workplace diseases, showing a continuous increase and affecting about 50 million workers per year. The financial cost of the MSDs is approximately 2% of the total EU GDP. The main cause of workplace MSDs is the execution of repetitive tasks (62%) which leads to the muscle fatigue accumulation. The main ergonomic factors that affect the muscle fatigue accumulation during the execution of load lifting tasks are the non-ergonomic working postures, the execution of repetitive tasks, the weight of the lifting load and the inadequate time of rest for the muscle recovery. Musculoskeletal disorders of the low back are the most frequent when performing repetitive load lifting and almost always cause pain in the lumbar region.The aim of this work was to investigate the phenomenon of muscle fatigue accumulation in the upper limbs and in the low back regions during the execution of repetitive load lifting, to detect the crucial muscle fatigue accumulation and to define muscle fatigue indicators-parameters. These fatigue indicators determine when the accumulation of muscle fatigue reaches a high level and specify when the workers should temporarily stop their work (rest-break), in order to reduce the risk of causing musculoskeletal injuries. In addition, the fatigue indicators could be a useful tool for organizing the work-rest ratio.Three different experimental methods were performed to investigate muscle fatigue accumulation during repetitive load lifting tasks. The first one was a kinesiological method which aimed to detect muscle fatigue accumulation and to define fatigue indicators of the upper limbs during the repetitive load lifting from the ground to supermarket shelves, by performing two different lifting techniques (using the upper limbs above the shoulder level and below the shoulder level). For this purpose, the electromyography methodology, the video recording of the movement of certain upper limb joints methodology and the perceptible fatigue methodology were applied. By using the electromyography methodology, the electrical activity of the deltoid muscle was recorded and analyzed. The video recording methodology was used in order the kinematic parameters (velocity, acceleration, torque) of specific upper limbs joints to be analyzed, and the perceptible fatigue methodology was used in order the subjective assessment of the volunteers’ fatigue level to be recorded. The second experimental method was an electromyography method where the dorsal muscle electrical activity was recorded, analyzed and compared to the results of the volunteers’ perceptible fatigue values. The purpose of the second experimental method was the Time to Substantial Fatigue Onset (TSFO) index in the low back region to be defined and the effect of rest-breaks on muscular recovery to be studied, during the repetitive load lifting from the ground to a workbench. The electromyogram of the dorsal muscle was recorded, analyzed and compared to the results of the volunteers’ perceptible fatigue values. The third experiment method aimed to investigate the possible correlation between the low back musculoskeletal system variability and the muscle fatigue accumulation. For this purpose, the convergence/divergence of the low back trajectories was examined and compared with the corresponding ones in different stages of muscle fatigue, as well as with the results of the volunteers’ perceptible fatigue values of these fatigue stages, in order the TSFO index to be defined, during the repetitive load lifting from the ground to a workbench.The analysis of the experimental data led to the following conclusions:1)One of the main conclusions is that the volunteers do not perceive the crucial muscle fatigue accumulation early at the appropriate time and continue to do their work resulting in pain or intense discomfort, even possible muscle damage. This conclusion enhances the view taken in the thesis that the fatigue indicators are necessary to be defined when an ergonomic organization of the work-rest ratio is designed.2)The results from the investigation of the effect of rest-breaks to the muscle recovery, showed that during the execution of repetitive load lifting tasks, the duration of the rest-breaks should increase progressively with the work task duration, in order the optimal muscle recovery to be achieved.3)The results derived from the Lyapunov analysis showed that the variability of the low back musculoskeletal system kinematic trajectories corresponded to different stages of neuromuscular control, influenced directly by the muscle fatigue accumulation.Μελέτες της Eurostat από το 1995, με στόχο την καταγραφή δεδομένων για τις επαγγελματικές παθήσεις των χώρων εργασίας στην Ε.Ε., έδειξαν ότι οι μυοσκελετικές παθήσεις (ΜΣΠ) αναφέρονται στις 3 περισσότερο συχνές παθήσεις, παρουσιάζοντας συνεχή αύξηση και προσβάλλοντας περίπου 50 εκατομμύρια εργαζόμενους ετησίως. Το οικονομικό κόστος των ΜΣΠ φθάνει, κατά προσέγγιση, στο 2% του συνολικού ΑΕΠ της Ε.Ε.. Η κυριότερη αιτία πρόκλησης ΜΣΠ στους χώρους εργασίας είναι η εκτέλεση επαναλαμβανόμενων εργασιών, σε ποσοστό 62%, που οδηγεί σε κρίσιμη συσσώρευση μυϊκής κόπωσης. Οι κυριότεροι εργονομικοί παράγοντες που επιδρούν στην συσσώρευση της μυϊκής κόπωσης κατά την ανύψωση φορτίων, είναι η μη-εργονομική στάση εργασίας, η εκτέλεση επαναλαμβανόμενων κινήσεων, το βάρος του ανυψώμενου φορτίου καθώς και ο ανεπαρκής χρόνος διαλείμματος για την μυϊκή αποκατάσταση. Σκοπός της διατριβής ήταν η διερεύνηση του φαινομένου της συσσώρευσης της μυϊκής κόπωσης στα άνω άκρα και στην περιοχή της μέσης κατά την επαναλαμβανόμενη ανύψωση ελαφριού φορτίου και ο προσδιορισμός δεικτών-παραμέτρων της συσσώρευσης κρίσιμης μυϊκής κόπωσης. Αυτοί οι δείκτες κόπωσης προσδιορίζουν τη χρονική περίοδο όπου γίνεται κρίσιμη η συσσώρευση της μυϊκής κόπωσης ώστε οι εργαζόμενοι να καθορίζουν την προσωρινή παύση της εργασίας τους (διάλειμμα) με στόχο την μείωση του κινδύνου πρόκλησης μυοσκελετικών βλαβών. Επιπροσθέτως, οι δείκτες αποτελούν ένα χρήσιμο εργαλείο οργάνωσης του ωραρίου εργασίας (εργασία – διάλειμμα).Στη διατριβή εφαρμόστηκαν τρείς πειραματικές μέθοδοι για την διερεύνηση της συσσώρευσης της μυϊκής κόπωσης κατά την εκτέλεση εργασιών επαναλαμβανόμενης ανύψωσης φορτίου. Η πρώτη μέθοδος είχε στόχο τον προσδιορισμό δεικτών συσσώρευσης της μυϊκής κόπωσης των άνω άκρων κατά την επαναλαμβανόμενη ανύψωση ελαφριού φορτίου σε ράφια σουπερμάρκετ, εκτελώντας δυο διαφορετικές τεχνικές ανύψωσης (χρησιμοποιώντας τα άνω άκρα πάνω από το επίπεδο των ώμων και κάτω από το επίπεδο των ώμων με συμμετοχή του κορμού). Σε αυτή τη πειραματική διαδικασία εφαρμόστηκαν οι μεθοδολογίες της ηλεκτρομυογραφίας, της βιντεοσκόπησης της κίνησης συγκεκριμένων αρθρώσεων των άνω άκρων καθώς και η μεθοδολογία της αισθητής κόπωσης του Borg. Με τη μεθοδολογία της ηλεκτρομυογραφίας καταγράφηκε και αναλύθηκε η ηλεκτρική δραστηριότητα του δελτοειδούς μυός. Με τη μεθοδολογία της βιντεοσκόπησης αναλύθηκαν οι κινηματικές παράμετροι (ταχύτητα, επιτάχυνση, ροπή) των εξεταζόμενων αρθρώσεων, ενώ με τη μεθοδολογία της αισθητής κόπωσης καταγράφηκε η υποκειμενική εκτίμηση των εθελοντών για το επίπεδο της κόπωσής τους. Στη δεύτερη πειραματική μέθοδο σκοπός ήταν ο προσδιορισμός του δείκτη του Χρόνου Έναρξης της συσσώρευσης Κρίσιμης Κόπωσης (ΧΕΚΚ) στη περιοχή της μέσης και η διερεύνηση της επίδρασης των διαλειμμάτων στην μυϊκή αποκατάσταση, κατά την επαναλαμβανόμενη ανύψωση ελαφριού φορτίου από το έδαφος σε πάγκο εργασίας, με καταγραφή ηλεκτρομυογραφήματος του ραχιαίου μυός και με καταγραφή του επιπέδου της αισθητής κόπωσης των εθελοντών. Η τρίτη πειραματική μέθοδος είχε στόχο να ερευνηθεί η πιθανή συσχέτιση μεταξύ της μεταβλητότητας του μυοσκελετικού συστήματος της περιοχής της μέσης και της συσσώρευσης της μυϊκής κόπωσης. Για αυτό το σκοπό εφαρμόστηκε η μεθοδολογία Lyapunov μέσω της οποίας μελετήθηκε η συσχέτιση μεταξύ της σύγκλισης / απόκλισης των κινηματικών παραμέτρων του μυοσκελετικού συστήματος της μέσης, όπως είναι οι σχηματιζόμενες από τους σπονδύλους τροχιές, και των διαφόρων σταδίων της μυϊκής κόπωσης. Τα αποτελέσματα συγκρίθηκαν με τις μετρήσεις της αισθητής κόπωσης των εθελοντών προκειμένου να προσδιοριστεί ο δείκτης ΧΕΚΚ κατά την επαναλαμβανόμενη ανύψωση ελαφριού φορτίου από το έδαφος σε πάγκο εργασίας.Η ανάλυση των πειραματικών δεδομένων οδήγησε στην εξαγωγή συμπερασμάτων:1)Ένα από τα κυριότερα συμπεράσματα της διατριβής είναι ότι οι εθελοντές δεν αντιλαμβάνονται έγκαιρα την συσσώρευση της μυϊκής κόπωσης, παρά μόνον όταν αυτή προκαλέσει πόνο, ή έντονη δυσφορία κατά την εργασία ή μυϊκή βλάβη. Το συμπέρασμα αυτό ενδυναμώνει την αρχική θέση της διατριβής που αφορά στην αναγκαιότητα προσδιορισμού δεικτών κόπωσης για την εργονομική οργάνωση του ωραρίου της εργασίας (εργασία/διάλειμμα).2)Από τη διερεύνηση της επίδρασης των διαλειμμάτων προέκυψε το συμπέρασμα ότι κατά τη διάρκεια εκτέλεσης επαναλαμβανόμενου έργου πρέπει να εφαρμόζονται προοδευτικά αυξανόμενης διάρκειας διαλείμματα, ώστε να επιτυγχάνεται η βέλτιστη μυϊκή αποκατάσταση.3)Τα αποτελέσματα από την εφαρμογή της ανάλυσης Lyapunov έδειξαν ότι η μεταβλητότητα των κινηματικών τροχιών του μυοσκελετικού συστήματος της μέσης εμφάνισε διαφορετικά στάδια νευρομυϊκού ελέγχου του συστήματος, σαφώς επηρεασμένα από την συσσώρευση μυϊκής κόπωσης

Thromboembolic Disease in Patients With Cancer and COVID-19:Risk Factors, Prevention and Practical Thromboprophylaxis Recommendations–State-of-the-Art

Cancer and COVID-19 are both well-established risk factors predisposing to thrombosis. Both disease entities are correlated with increased incidence of venous thrombotic events through multifaceted pathogenic mechanisms involving the interaction of cancer cells or SARS-CoV2 on the one hand and the coagulation system and endothelial cells on the other hand. Thromboprophylaxis is recommended for hospitalized patients with active cancer and high-risk outpatients with cancer receiving anticancer treatment. Universal thromboprophylaxis with a high prophylactic dose of low molecular weight heparins (LMWH) or therapeutic dose in select patients, is currently indicated for hospitalized patients with COVID-19. Also, prophylactic anticoagulation is recommended for outpatients with COVID-19 at high risk for thrombosis or disease worsening. However, whether there is an additive risk of thrombosis when a patient with cancer is infected with SARSCoV2 remains unclear. In the current review, we summarize and critically discuss the literature regarding the epidemiology of thrombotic events in patients with cancer and concomitant COVID-19, the thrombotic risk assessment, and the recommendations on thromboprophylaxis for this subgroup of patients. Current data do not support an additive thrombotic risk for patients with cancer and COVID-19. Of note, patients with cancer have less access to intensive care unit care, a setting associated with high thrombotic risk. Based on current evidence, patients with cancer and COVID-19 should be assessed with well-established risk assessment models for medically ill patients and receive thromboprophylaxis, preferentially with LMWH, according to existing recommendations. Prospective trials on well-characterized populations do not exist