The effect of Tai Chi Chuan in reducing falls among elderly people: design of a randomized clinical trial in the Netherlands [ISRCTN98840266]

BACKGROUND: Falls are a significant public health problem. Thirty to fifty percent of the elderly of 65 years and older fall each year. Falls are the most common type of accident in this age group and can result in fractures and subsequent disabilities, increased fear of falling, social isolation, decreased mobility, and even an increased mortality. Several forms of exercise have been associated with a reduced risk of falling and with a wide range of physiological as well as psychosocial health benefits. Tai Chi Chuan seems to be the most promising form of exercise in the elderly, but the evidence is still controversial. In this article the design of a randomized clinical trial is presented. The trial evaluates the effect of Tai Chi Chuan on fall prevention and physical and psychological function in older adults. METHODS/DESIGN: 270 people of seventy years and older living at home will be identified in the files of the participating general practitioners. People will be asked to participate when meeting the following inclusion criteria: have experienced a fall in the preceding year or suffer from two of the following risk factors: disturbed balance, mobility problems, dizziness, or the use of benzodiazepines or diuretics. People will be randomly allocated to either the Tai Chi Chuan group (13 weeks, twice a week) or the no treatment control group. The primary outcome measure is the number of new falls, measured with a diary. The secondary outcome measures are balance, fear of falling, blood pressure, heart rate, lung function parameters, physical activity, functional status, quality of life, mental health, use of walking devices, medication, use of health care services, adjustments to the house, severity of fall incidents and subsequent injuries. Process parameters will be measured to evaluate the Tai Chi Chuan intervention. A cost-effectiveness analysis will be carried out alongside the evaluation of the clinical results. Follow-up measurements will be collected at 3, 6 and 12 months after randomization. DISCUSSION: As far as we know this is the first trial in Europe considering Tai Chi Chuan and fall prevention. This project will answer a pragmatic research question regarding the efficacy of Tai Chi Chuan regarding fall reduction

Exercise for reducing fear of falling in older people living in the community

Background: Fear of falling is common in older people and associated with serious physical and psychosocial consequences. Exercise (planned, structured, repetitive and purposive physical activity aimed at improving physical fitness) may reduce fear of falling by improving strength, gait, balance and mood, and reducing the occurrence of falls. Objectives: To assess the effects (benefits, harms and costs) of exercise interventions for reducing fear of falling in older people living in the community. Search methods: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (July 2013), the Central Register of Controlled Trials (CENTRAL 2013, Issue 7), MEDLINE (1946 to July Week 3 2013), EMBASE (1980 to 2013 Week 30), CINAHL (1982 to July 2013), PsycINFO (1967 to August 2013), AMED (1985 to August 2013), the World Health Organization International Clinical Trials Registry Platform (accessed 7 August 2013) and Current Controlled Trials (accessed 7 August 2013). We applied no language restrictions. We handsearched reference lists and consulted experts. Selection criteria: We included randomised and quasi-randomised trials that recruited community-dwelling people (where the majority were aged 65 and over) and were not restricted to specific medical conditions (e.g. stroke, hip fracture). We included trials that evaluated exercise interventions compared with no intervention or a non-exercise intervention (e.g. social visits), and that measured fear of falling. Exercise interventions were varied; for example, they could be 'prescriptions' or recommendations, group-based or individual, supervised or unsupervised. Data collection and analysis: Pairs of review authors independently assessed studies for inclusion, assessed the risk of bias in the studies and extracted data. We combined effect sizes across studies using the fixed-effect model, with the random-effect model used where significant statistical heterogeneity was present. We estimated risk ratios (RR) for dichotomous outcomes and incidence rate ratios (IRR) for rate outcomes. We estimated mean differences (MD) where studies used the same continuous measures and standardised mean differences (SMD) where different measures or different formats of the same measure were used. Where possible, we performed various, usually prespecified, sensitivity and subgroup analyses. Main results: We included 30 studies, which evaluated 3D exercise (Tai Chi and yoga), balance training or strength and resistance training. Two of these were cluster-randomised trials, two were cross-over trials and one was quasi-randomised. The studies included a total of 2878 participants with a mean age ranging from 68 to 85 years. Most studies included more women than men, with four studies recruiting women only. Twelve studies recruited participants at increased risk of falls; three of these recruited participants who also had fear of falling. Poor reporting of the allocation methods in the trials made it difficult to assess the risk of selection bias in most studies. All of the studies were at high risk of performance and detection biases as there was no blinding of participants and outcome assessors and the outcomes were self reported. Twelve studies were at high risk of attrition bias. Using GRADE criteria, we judged the quality of evidence to be 'low' for fear of falling immediately post intervention and 'very low' for fear of falling at short or long-term follow-up and all other outcomes. Exercise interventions were associated with a small to moderate reduction in fear of falling immediately post intervention (SMD 0.37 favouring exercise, 95% confidence interval (CI) 0.18 to 0.56; 24 studies; 1692 participants, low quality evidence). Pooled effect sizes did not differ significantly between the different scales used to measure fear of falling. Although none of the sensitivity analyses changed the direction of effect, the greatest reduction in the size of the effect was on removal of an extreme outlier study with 73 participants (SMD 0.24 favouring exercise, 95% CI 0.12 to 0.36). None of our subgroup analyses provided robust evidence of differences in effect in terms of either the study primary aim (reduction of fear of falling or other aim), the study population (recruitment on the basis of increased falls risk or not), the characteristics of the study exercise intervention or the study control intervention (no treatment or alternative intervention). However, there was some weak evidence of a smaller effect, which included no reduction, of exercise when compared with an alternative control. There was very low quality evidence that exercise interventions may be associated with a small reduction in fear of falling up to six months post intervention (SMD 0.17, 95% CI -0.05 to 0.38; four studies, 356 participants) and more than six months post intervention (SMD 0.20, 95% CI -0.01 to 0.41; three studies, 386 participants). Very low quality evidence suggests exercise interventions in these studies that also reported on fear of falling reduced the risk of falling measured either as participants incurring at least one fall during follow-up or the number of falls during follow-up. Very low quality evidence from four studies indicated that exercise interventions did not appear to reduce symptoms of depression or increase physical activity. The only study reporting the effects of exercise interventions on anxiety found no difference between groups. No studies reported the effects of exercise interventions on activity avoidance or costs. It is important to remember that our included studies do not represent the totality of the evidence of the effect of exercise interventions on falls, depression, anxiety or physical activity as our review only includes studies that reported fear of falling. Authors' conclusions: Exercise interventions in community-dwelling older people probably reduce fear of falling to a limited extent immediately after the intervention, without increasing the risk or frequency of falls. There is insufficient evidence to determine whether exercise interventions reduce fear of falling beyond the end of the intervention or their effect on other outcomes. Although further evidence from well-designed randomised trials is required, priority should be given to establishing a core set of outcomes that includes fear of falling for all trials examining the effects of exercise interventions in older people living in the community

On the Emergence of Biologically-Plausible Representation in Recurrent Neural Networks for Navigation

Biologically plausible representations have been found to emerge in particular recurrent neural networks when training on path-integration [1, 2]. This report explores factors influencing the occurrence of entorhinal-like representations in recurrent neural networks. Reproducing simplified models from existing studies and created a hybrid model to explore additional factors, including the input features, structural properties, and regularization techniques in recurrent neural networks. Additional experiments evaluate the difference in training performance when entorhinal-like representations are introduced to a recurrent neural network. This report also assesses existing and experimental visualization techniques in their ability to visualize the performance and representation of recurrent neurons. While some experiments show specialized representations, mostly due to regularization; none of the experiments showed typical entorhinal-like representation. These results show how sensitive the emergence of biologically-plausible representations is to network conditions and training procedure,casting some doubt on the generality of the conclusions proposed in earlier work.Computer Scienc

Productie van trimethylolpropaan

Document uit de collectie Chemische ProcestechnologieDelftChemTechApplied Science

ci-group/revolve2: 1.0.0rc1

<p><strong>New features</strong></p> <ul> <li>Reworked interface for simulation and modular robot simulation.</li> <li>Added feedback for brains. Implemented for active hinge positions.</li> <li>Added v2 hardware support in simulation.</li> <li>Armature, kv, and kp can now be set directly in ActiveHinge.</li> <li>RPi controller has been reworked to be a lot easier to use. Remote has been removed temporarily but we will be added again soon in better shape.</li> </ul> <p><strong>Documentation and general project things</strong></p> <ul> <li>Many and various improvements to documentation.</li> <li><ul> <li>Various improvements and fixes to the CI.</li> </ul> </li> <li><ul> <li>Improved and added examples.</li> </ul> </li> <li><ul> <li>Updated project layout and pyproject.toml files.</li> </ul> </li> </ul> <p><strong>Bug fixes and minor updates</strong></p> <ul> <li>Fixed bug in geometries where colors were not properly initialized.</li> <li>Added Vector2d and replaced Vector3d wherever applicable.</li> <li>Removed warning message for NamedTemporaryFile on Windows, as the applied backup strategy turns out to be reliable, making the * Various minor refactors and cleanups.message superfluous.</li> </ul> <p><strong>Regressions</strong> RPi controller remote has been removed, but will be added again in the next version in an improved form.</p&gt

Co-optimizing for task performance and energy efficiency in evolvable robots

Evolutionary robotics is concerned with optimizing autonomous robots for one or more specific tasks. Remarkably, the energy needed to operate autonomously is hardly ever considered. This is quite striking because energy consumption is a crucial factor in real-world applications and ignoring this aspect can increase the reality gap. In this paper, we aim to mitigate this problem by extending our robot simulator framework with a model of a battery module and studying its effect on robot evolution. The key idea is to include energy efficiency in the definition of fitness. The robots will need to evolve to achieve high gait speed and low energy consumption. Since our system evolves the robots’ morphologies as well as their controllers, we investigate the effect of the energy extension on the morphologies and on the behavior of the evolved robots. The results show that by including the energy consumption, the evolution is not only able to achieve higher task performance (robot speed), but it reaches good performance faster. Inspecting the evolved robots and their behaviors discloses that these improvements are not only caused by better morphologies, but also by better settings of the robots’ controller parameters

Impact of energy efficiency on the morphology and behaviour of evolved robots

Most evolutionary robotics studies focus on evolving some targeted behavior without considering energy usage. In this paper, we extend our simulator with a battery model to take energy consumption into account in a system where robot morphologies and controllers evolve simultaneously. The results show that including the energy consumption in the fitness in a multi-objective fashion reduces the average size of robot bodies while reducing their speed. However, robots generated without size reduction can achieve speeds comparable to robots from the baseline set

The Influence of Robot Traits and Evolutionary Dynamics on the Reality Gap

The elephant in the room for evolutionary robotics is the reality gap. In the history of the field, several studies investigated this phenomenon on fixed robot morphologies where only the controllers evolved. This paper addresses the reality gap in a wider context, in a system where both morphologies and controllers evolve. In this context the morphology of the robots becomes a variable with a currently unknown influence. To examine this influence, we construct a test suite of robots with various morphologies and evolve their controllers for an effective gait. Comparing the simulated and the real-world performance of evolved controllers sampled at different generations during the evolutionary process, we gain new insights into the factors that influence the reality gap