Improving lateral stability in older adults at risk of falls

Age-related changes in the ability to control lateral body motion have been associated with falls. Maintenance of lateral stability requires activation of appropriate muscle groups, primarily the hip abductors and adductors. Lateral trainer exercise has potential for increasing hip abductor muscle strength and rate of force development (RFD) and improving lateral stability by providing high velocity resistance training for the hip abductor muscles. The purpose of this dissertation was to examine lateral trainer exercise as a novel intervention for improving lateral stability in older adults. In the first project, forty-two older adults at high and low risk of falls were recruited to participate in kinematic and electromyographic data collection during lateral trainer, lateral step-up and side leg raise exercises performed at self-selected and maximal speeds. Results showed that the lateral trainer exercise can be performed safely by older adults and can provide an adequate level of hip abductor muscle activation for stimulating muscle strength adaptation. The side leg raise exercise produced the highest level of neuromuscular activation, however, indicating that this exercise may be the most beneficial for healthy older adults of the 3 hip abductor strengthening exercises investigated. In the second project, 21 older adults at risk of falls participated in a small randomized controlled trial of the effects of a 10-week lateral trainer exercise program on balance confidence, hip abductor maximal muscle strength and rate of force development, and lateral stability. Results showed that older adults in the exercise group performed better than those in the control group on one dynamic balance test, a timed 360o turn, but not on the other measured outcomes. The limited intervention effects may be related to the small sample size, the relatively high level of balance confidence and physical function of the older adults in the sample, and possible inadequacies in the duration of the exercise intervention and/or in the level of resistance used. Lateral trainer exercise provides an addition to the variety of hip abductor exercises from which older adults can choose. Additional research is needed to identify optimal intervention strategies for improving lateral stability in older adults. A multifactorial approach, one that takes the principle of specificity of training into account by incorporating specific balance training as well as strength training, may produce the best outcomes

Repetitive Eccentric Muscle Contractions Increase Torque Unsteadiness in the Human Triceps Brachii

Torque steadiness and low-frequency fatigue (LFF) were examined in the human triceps brachii after concentric or eccentric fatigue protocols. Healthy young males (n = 17) performed either concentric or eccentric elbow extensor contractions until the eccentric maximal voluntary torque decreased to 75% of pre-fatigue for both (concentric and eccentric) protocols. The number of concentric contractions was greater than the number of eccentric contractions needed to induce the same 25% decrease in eccentric MVC torque (52.2 ± 2.9 vs. 41.5 ± 2.1 for the concentric and eccentric protocols, respectively, p \u3c .01). The extent of peripheral fatigue was 12% greater after the concentric compared to the eccentric protocol (twitch amplitude), whereas LFF (increase in double pulse torque/single pulse torque), was similar across protocols. Steadiness, or the ability for a subject to hold a submaximal isometric contraction, was 20% more inpaired during the Ecc protocol (p = .052). Similarly, the EMG activity required to hold the torque steady was nearly 20% greater after the eccentric compared to concentric protocol. These findings support that task dependent eccentric contractions preferentially alter CNS control during a precision based steadiness task

FML-based Prediction Agent and Its Application to Game of Go

In this paper, we present a robotic prediction agent including a darkforest Go engine, a fuzzy markup language (FML) assessment engine, an FML-based decision support engine, and a robot engine for game of Go application. The knowledge base and rule base of FML assessment engine are constructed by referring the information from the darkforest Go engine located in NUTN and OPU, for example, the number of MCTS simulations and winning rate prediction. The proposed robotic prediction agent first retrieves the database of Go competition website, and then the FML assessment engine infers the winning possibility based on the information generated by darkforest Go engine. The FML-based decision support engine computes the winning possibility based on the partial game situation inferred by FML assessment engine. Finally, the robot engine combines with the human-friendly robot partner PALRO, produced by Fujisoft incorporated, to report the game situation to human Go players. Experimental results show that the FML-based prediction agent can work effectively.Comment: 6 pages, 12 figures, Joint 17th World Congress of International Fuzzy Systems Association and 9th International Conference on Soft Computing and Intelligent Systems (IFSA-SCIS 2017), Otsu, Japan, Jun. 27-30, 201

A computational method for estimating trunk muscle activations during gait using lower extremity muscle synergies

One of the surgical treatments for pelvic sarcoma is the restoration of hip function with a custom pelvic prosthesis after cancerous tumor removal. The orthopedic oncologist and orthopedic implant company must make numerous often subjective decisions regarding the design of the pelvic surgery and custom pelvic prosthesis. Using personalized musculoskeletal computer models to predict post-surgery walking function and custom pelvic prosthesis loading is an emerging method for making surgical and custom prosthesis design decisions in a more objective manner. Such predictions would necessitate the estimation of forces generated by muscles spanning the lower trunk and all joints of the lower extremities. However, estimating trunk and leg muscle forces simultaneously during walking based on electromyography (EMG) data remains challenging due to the limited number of EMG channels typically used for measurement of leg muscle activity. This study developed a computational method for estimating unmeasured trunk muscle activations during walking using lower extremity muscle synergies. To facilitate the calibration of an EMG-driven model and the estimation of leg muscle activations, EMG data were collected from each leg. Using non-negative matrix factorization, muscle synergies were extracted from activations of leg muscles. On the basis of previous studies, it was hypothesized that the time-varying synergy activations were shared between the trunk and leg muscles. The synergy weights required to reconstruct the trunk muscle activations were determined through optimization. The accuracy of the synergy-based method was dependent on the number of synergies and optimization formulation. With seven synergies and an increased level of activation minimization, the estimated activations of the erector spinae were strongly correlated with their measured activity. This study created a custom full-body model by combining two existing musculoskeletal models. The model was further modified and heavily personalized to represent various aspects of the pelvic sarcoma patient, all of which contributed to the estimation of trunk muscle activations. This proposed method can facilitate the prediction of post-surgery walking function and pelvic prosthesis loading, as well as provide objective evaluations for surgical and prosthesis design decisions

The effects of combined transcranial brain stimulation and a 4-week visuomotor stepping training on voluntary step initiation in persons with chronic stroke—a pilot study

PurposeEvidence suggests that transcranial direct current stimulation (tDCS) can enhance motor performance and learning of hand tasks in persons with chronic stroke (PCS). However, the effects of tDCS on the locomotor tasks in PCS are unclear. This pilot study aimed to: (1) determine aggregate effects of anodal tDCS combined with step training on improvements of the neural and biomechanical attributes of stepping initiation in a small cohort of persons with chronic stroke (PCS) over a 4-week training program; and (2) assess the feasibility and efficacy of this novel approach for improving voluntary stepping initiation in PCS.MethodsA total of 10 PCS were randomly assigned to one of two training groups, consisting of either 12 sessions of VST paired with a-tDCS (n = 6) or sham tDCS (s-tDCS, n = 4) over 4 weeks, with step initiation (SI) tests at pre-training, post-training, 1-week and 1-month follow-ups. Primary outcomes were: baseline vertical ground reaction force (B-vGRF), response time (RT) to initiate anticipatory postural adjustment (APA), and the retention of B-VGRF and RT.Resultsa-tDCS paired with a 4-week VST program results in a significant increase in paretic weight loading at 1-week follow up. Furthermore, a-tDCS in combination with VST led to significantly greater retention of paretic BWB compared with the sham group at 1 week post-training.Clinical implicationsThe preliminary findings suggest a 4-week VST results in improved paretic limb weight bearing (WB) during SI in PCS. Furthermore, VST combined with a-tDCS may lead to better retention of gait improvements (NCT04437251) (https://classic.clinicaltrials.gov/ct2/show/NCT04437251)

Budget impact analysis of robotic exoskeleton use for locomotor training following spinal cord injury in four SCI Model Systems

Background We know little about the budget impact of integrating robotic exoskeleton over-ground training into therapy services for locomotor training. The purpose of this study was to estimate the budget impact of adding robotic exoskeleton over-ground training to existing locomotor training strategies in the rehabilitation of people with spinal cord injury. Methods A Budget Impact Analysis (BIA) was conducted using data provided by four Spinal Cord Injury (SCI) Model Systems rehabilitation hospitals. Hospitals provided estimates of therapy utilization and costs about people with spinal cord injury who participated in locomotor training in the calendar year 2017. Interventions were standard of care walking training including body-weight supported treadmill training, overground training, stationary robotic systems (i.e., treadmill-based robotic gait orthoses), and overground robotic exoskeleton training. The main outcome measures included device costs, training costs for personnel to use the device, human capital costs of locomotor training, device demand, and the number of training sessions per person with SCI. Results Robotic exoskeletons for over-ground training decreased hospital costs associated with delivering locomotor training in the base case analysis. This analysis assumed no difference in intervention effectiveness across locomotor training strategies. Providing robotic exoskeleton overground training for 10% of locomotor training sessions over the course of the year (range 226–397 sessions) results in decreased annual locomotor training costs (i.e., net savings) between $1114 to$4784 per annum. The base case shows small savings that are sensitive to parameters of the BIA model which were tested in one-way sensitivity analyses, scenarios analyses, and probability sensitivity analyses. The base case scenario was more sensitive to clinical utilization parameters (e.g., how often devices sit idle and the substitution of high cost training) than device-specific parameters (e.g., robotic exoskeleton device cost or device life). Probabilistic sensitivity analysis simultaneously considered human capital cost, device cost, and locomotor device substitution. With probabilistic sensitivity analysis, the introduction of a robotic exoskeleton only remained cost saving for one facility. Conclusions Providing robotic exoskeleton for over-ground training was associated with lower costs for the locomotor training of people with SCI in the base case analyses. The analysis was sensitive to parameter assumptions

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