Serious gaming to generate separated and consistent EMG patterns in pattern-recognition prosthesis control

Pattern-Recognition (PR) control of upper-limb prosthetics has shown inconsistent results outside lab settings, which might be due to the inadequacy of users’ electromyogram (EMG) patterns. To improve the separability and consistency of their EMG, users can receive training. Conventional training uses an internal focus of attention as prosthesis users focus on the muscle contractions of their (phantom) hand together with explicit learning processes facilitated by a coach guiding the user. In this study we investigated if an alternative training paradigm using an external focus of attention exploiting implicit learning processes based on serious gaming without a coach could lead to more separable and consistent EMG. Able-bodied participants (N = 25; mean age 22 years, 13 females) were recruited and followed conventional or game training for five days. In conventional training, participants performed the Motion Test thrice daily and received coaching on how to adapt their muscle contractions. In game training, participants controlled an avatar using a direct mapping from electrode to avatar direction. The participants utilized implicit learning processes, by exploring which muscle contractions made the avatar go in which directions. Performance in both groups was evaluated by using the Motion Test in a pre/post-test design. Training resulted in improved performance, with no differences between training paradigms. Participants who followed game training showed 51% more separated EMG patterns. EMG pattern consistency did not change over training. It was concluded that serious game training using an external focus of attention and implicit learning can be considered as a viable alternative to conventional training.</p

Exploring the relationship between EMG feature space characteristics and control performance in machine learning myoelectric control

In myoelectric machine learning (ML) based control, it has been demonstrated that control performance usually increases with training, but it remains largely unknown which underlying factors govern these improvements. It has been suggested that the increase in performance originates from changes in characteristics of the Electromyography (EMG) patterns, such as separability or repeatability. However, the relation between these EMG metrics and control performance has hardly been studied. We assessed the relation between three common EMG feature space metrics (separability, variability and repeatability) in 20 able bodied participants who learned ML myoelectric control in a virtual task over 15 training blocks on 5 days. We assessed the change in offline and real-time performance, as well as the change of each EMG metric over the training. Subsequently, we assessed the relation between individual EMG metrics and offline and real-time performance via correlation analysis. Last, we tried to predict real-time performance from all EMG metrics via L2-regularized linear regression. Results showed that real-time performance improved with training, but there was no change in offline performance or in any of the EMG metrics. Furthermore, we only found a very low correlation between separability and real-time performance and no correlation between any other EMG metric and real-time performance. Finally, real-time performance could not be successfully predicted from all EMG metrics employing L2-regularized linear regression. We concluded that the three EMG metrics and real-time performance appear to be unrelated

The effect of feedback during training sessions on learning pattern-recognition based prosthesis control

Human-machine interfaces have not yet advanced to enable intuitive control of multiple degrees of freedom as offered by modern myoelectric prosthetic hands. Pattern Recognition (PR) control has been proposed to make human-machine interfaces in myoelectric prosthetic hands more intuitive, but it requires the user to generate high-quality, i.e., consistent and separable, electromyogram (EMG) patterns. To generate such patterns, user training is required and has shown promising results. However, how different levels of feedback affect effectivity in training differently, has not been established yet. Furthermore, a correlation between qualities of the EMG patterns (the focus of training) and user performance has not been shown yet. In this study, 37 able-bodied participants (mean age 21 years, 19 males) were recruited and trained PR control over five days. Three levels of feedback were tested for their effectiveness: no external feedback, visual feedback and visual feedback with coaching. Training resulted in improved performance from pre-to post-test with no interaction effect of feedback. Feedback did however affect the quality of the EMG patterns where people who did not receive external feedback generated higher amplitude patterns. A weak correlation was found between a principal component, composed of EMG amplitude and pattern variability, and performance. Our results show that training is highly effective in improving PR control regardless of feedback and that none of the quality metrics correlate with performance. We discuss how different levels of feedback can be leveraged to improve PR control training

Should Hands Be Restricted When Measuring Able-Bodied Participants To Evaluate Machine Learning Controlled Prosthetic Hands?

OBJECTIVE: When evaluating methods for machine-learning controlled prosthetic hands, able-bodied participants are often recruited, for practical reasons, instead of participants with upper limb absence (ULA). However, able-bodied participants have been shown to often perform myoelectric control tasks better than participants with ULA. It has been suggested that this performance difference can be reduced by restricting the wrist and hand movements of able-bodied participants. However, the effect of such restrictions on the consistency and separability of the electromyogram's (EMG) features remains unknown. The present work investigates whether the EMG separability and consistency between unaffected and affected arms differ and whether they change after restricting the unaffected limb in persons with ULA. METHODS: Both arms of participants with unilateral ULA were compared in two conditions: with the unaffected hand and wrist restricted or not. Furthermore, it was tested if the effect of arm and restriction is influenced by arm posture (arm down, arm in front, or arm up). RESULTS: Fourteen participants (two women, age=53.4±4.05) with acquired transradial limb loss were recruited. We found that the unaffected limb generated more separated EMG than the affected limb. Furthermore, restricting the unaffected hand and wrist lowered the separability of the EMG when the arm was held down. CONCLUSION: Limb restriction is a viable method to make the EMG of able-bodied participants more similar to that of participants with ULA. SIGNIFICANCE: Future research that evaluates methods for machine learning controlled hands in able-bodied participants should restrict the participants' hand and wrist

User training for machine learning controlled upper limb prostheses:a serious game approach

BACKGROUND: Upper limb prosthetics with multiple degrees of freedom (DoFs) are still mostly operated through the clinical standard Direct Control scheme. Machine learning control, on the other hand, allows controlling multiple DoFs although it requires separable and consistent electromyogram (EMG) patterns. Whereas user training can improve EMG pattern quality, conventional training methods might limit user potential. Training with serious games might lead to higher quality EMG patterns and better functional outcomes. In this explorative study we compare outcomes of serious game training with conventional training, and machine learning control with the users' own one DoF prosthesis. METHODS: Participants with upper limb absence participated in 7 training sessions where they learned to control a 3 DoF prosthesis with two grips which was fitted. Participants received either game training or conventional training. Conventional training was based on coaching, as described in the literature. Game-based training was conducted using two games that trained EMG pattern separability and functional use. Both groups also trained functional use with the prosthesis donned. The prosthesis system was controlled using a neural network regressor. Outcome measures were EMG metrics, number of DoFs used, the spherical subset of the Southampton Hand Assessment Procedure and the Clothespin Relocation Test. RESULTS: Eight participants were recruited and four completed the study. Training did not lead to consistent improvements in EMG pattern quality or functional use, but some participants improved in some metrics. No differences were observed between the groups. Participants achieved consistently better results using their own prosthesis than the machine-learning controlled prosthesis used in this study. CONCLUSION: Our explorative study showed in a small group of participants that serious game training seems to achieve similar results as conventional training. No consistent improvements were found in either group in terms of EMG metrics or functional use, which might be due to insufficient training. This study highlights the need for more research in user training for machine learning controlled prosthetics. In addition, this study contributes with more data comparing machine learning controlled prosthetics with Direct Controlled prosthetics

Secondary user relations in emerging mobile computing environments

Mobile technologies are enabling access to information in diverse environ.ments, and are exposing a wider group of individuals to said technology. Therefore, this paper proposes that a wider view of user relations than is usually considered in information systems research is required. Specifically, we examine the potential effects of emerging mobile technologies on end-­‐user relations with a focus on the ‘secondary user’, those who are not intended to interact directly with the technology but are intended consumers of the technology’s output. For illustration, we draw on a study of a U.K. regional Fire and Rescue Service and deconstruct mobile technology use at Fire Service incidents. Our findings provide insights, which suggest that, because of the nature of mobile technologies and their context of use, secondary user relations in such emerging mobile environments are important and need further exploration

Real-time detection of TDP1 activity using a fluorophore-quencher coupled DNA-biosensor

Real-time detection of enzyme activities may present the easiest and most reliable way of obtaining quantitative analyses in biological samples. We present a new DNA-biosensor capable of detecting the activity of the potential anticancer drug target tyrosyl-DNA phosphodiesterase 1 (TDP1) in a very simple, high throughput, and real-time format. The biosensor is specific for Tdp1 even in complex biological samples, such as human cell extracts, and may consequently find future use in fundamental studies as well as a cancer predictive tool allowing fast analyses of diagnostic cell samples such as biopsies. TDP1 removes covalent 3'DNA adducts in DNA single-strand break repair. This enzymatic activity forms the basis of the design of the TDP1-biosensor, which consists of a short hairpin-forming oligonucleotide having a 5'fluorophore and a 3'quencher brought in close proximity by the secondary structure of the biosensor. The specific action of TDP1 removes the quencher, thereby enabling optical detection of the fluorophore. Since the enzymatic action of TDP1 is the only "signal amplification" the increase in fluorescence may easily be followed in real-time and allows quantitative analyses of TDP1 activity in pure enzyme fractions as well as in crude cell extracts. In the present study we demonstrate the specificity of the biosensor, its ability to quantitatively detect up- or down-regulated TDP1 activity, and that it may be used for measuring and for analyzing the mechanism of TDP1 inhibition

Санитарно-эпидемиологическая экспертиза импортной пищевой продукции и продовольственного сырья как составляющая профилактического направления транспортной медицины

Санітарно епідеміологічна експертиза імпортної харчової продукції й продовольчої сировини (далі експертиза) є одним з пріоритетних напрямів діяльності транспортних підрозділів санепідслужби. Здійснюючи функцію по контролю, виявленню та попередженню впливу небезпечних факторів, пов’язаних з перевезенням вантажів, вона є однією зі складових частин профілактичного напряму транспортної медицини. Експертиза імпортованої продукції харчового призначення нерозривно пов’язана та базується на загальних принципах всієї державної політики у сфері безпеки харчової продукції та продовольчої сировини. Основою для проведення усього комплексу робіт санітарно епідеміологічного направлення є нормативна база, яка була сформована в нашій країні кілька десятиліть назад. Механізм визначення безпеки продукції та ті критерії оцінки, які були закладені в її основі, вимагають перегляду у відповідності з вимогами сьогодення та враховуючи розвиток міжнародних відносин. Зроблені деякі кроки у цьому напрямку. Наприклад, визначення експертизи у законі «Про внесення змін до закону України «Про якість та безпеку харчових продуктів та продовольчої сировини» поряд зі встановленням відповідності продукції нормативним вимогам передбачає оцінку ризику дії шкідливих факторів у процесі обігу харчових продуктів, що відповідає сучас ним вимогам до вирішення задач профілактичного напрямку, запобігання шкідливого впливу факторів, керування санітарно-епідеміологічною ситуацією взагалі та на етапі транспортування харчових грузів зокрема. Такий підхід потрібно враховувати при подальшому необхідному перегляді та формуванні нової нормативної бази.Sanіtarу epidemiological examination of imported foodstuffs and edible raw materials (then «examination») is one of the priority directions of transport sanіtarу epidemiological servise. Examination controls, discovers and prevents an influence of dangerous factors while in transportation of loads. So it’s one of the component of the transport medicine preventive activity. Examination of import foodstuffs and edible raw materials inseparably linked with and based on general principles of the food safety state policy. The foundation of the sanitary service work is the normative base, that was formed in our country about twenty years ago. It is necessary to review the mechanism of the food safety determination and its criteria in accordance with requirements of present day time and with account of the development of the international relations. One of taken steps in this direction is a characteristic of examination in law «About contributing the modification to law of the Ukraine «About quality and safety of foodstuffs and foodraw materials» where along with determination of the products correspondence to the normative requirements is provided forrisk assessment of the harmful factors in process of the turn of the food stuffs. Such approach corresponds with modern requests to decision of the prophylactic problems, prevention bad influence dangerous factors, management sanіtarу epidemiological situation in general and in step of transportation food cargo in particular. And it should be taken into account during the further necessary process of revision and forming the new normative base