Functional Implications of Impaired Control of Submaximal Hip Flexion Following Stroke

Introduction: We quantified sub-maximal torque regulation during low to moderate intensity isometric hip flexion contractions in individuals with stroke and the associations with leg function. Methods: 10 participants with chronic stroke and 10 controls performed isometric hip flexion contractions at 5%, 10%, 15%, 20%, and 40% of maximal voluntary contraction (MVC) in paretic, non-paretic, and control legs. Results: Participants with stroke had larger torque fluctuations (coefficient of variation, CV), for both the paretic and non-paretic legs, than controls (Pr2 =0.45) and Berg Balance Score (r2=0.38). At 5% MVC, there were larger torque fluctuations in the contralateral leg during paretic contractions compared with the control leg. Conclusions: Impaired low-force regulation of paretic leg hip flexion can be functionally relevant and related to control versus strength deficits post stroke

Stroke-related Changes in Neuromuscular Fatigue of the Hip Flexors and Functional Implications

Objective: The aim of this study was to compare stroke-related changes in hip flexor neuromuscular fatigue of the paretic leg during a sustained isometric submaximal contraction with those of the nonparetic leg and controls and to correlate fatigue with clinical measures of function. Design: Hip torques were measured during a fatiguing hip flexion contraction at 20% of the hip flexion maximal voluntary contraction in the paretic and nonparetic legs of 13 people with chronic stroke and 10 age-matched controls. In addition, the participants with stroke performed a fatiguing contraction of the paretic leg at the absolute torque equivalent to 20% maximal voluntary contraction of the nonparetic leg and were tested for self-selected walking speed (10-m Walk Test) and balance (Berg). Results: When matching the nonparetic target torque, the paretic hip flexors had a shorter time to task failure compared with the nonparetic leg and controls (P \u3c 0.05). The time to failure of the paretic leg was inversely correlated with the reduction of hip flexion maximal voluntary contraction torque. Self-selected walking speed was correlated with declines in torque and steadiness. Berg-Balance scores were inversely correlated with the force fluctuation amplitude. Conclusions: Fatigue and precision of contraction are correlated with walking function and balance after stroke

Wills, Trusts, and Estates

Between legislative and judicial activity, there have been a number of noteworthy developments and changes to the rules governing trusts and estates. Several of these developments turn on questions related to the role of fiduciaries, what responsibilities they have with respect to reporting as well as asset management, and when they can be removed. These questions concerning fiduciaries implicitly address the rights of beneficiaries and the protections available to them. New developments also will have multiple repercussions for estate planners and wealth managers. New planning strategies in response to changes in the law of undue influence may become important to consider and recent judicial opinions may influence a planner’s drafting decisions, particularly with respect to no-contest and arbitration clauses. Overall, the developments clarify the balance of rights and responsibilities allocated between settlors, beneficiaries, and fiduciaries and, in many cases, bolster the rights of beneficiaries and those under legal guardianship

Simulation Environment for Object Manipulation with Soft Robots in Shared Autonomy

The robots of today have grown to be of much more significant use than their predecessors. Robots are now being used in industries outside of the factory setting which can be seen primarily in the medical, transportation, and social fields. With robots taking on all of these new roles within our society, the establishment of robust human-robot collaboration is crucial in order for robots to be able to successfully complete desired tasks without becoming a hinderance to nearby humans. We explored this concept by implementing a shared-autonomy algorithm named MBSA (Motion Based Smart Assistance) to a soft robot simulation and testing out its performance against an object manipulation task. MBSA works such that it takes human user input and measures the distance to a desired target, such as a block, from the robot’s end-effector and applies a force in the direction of the target to the robot if it’s not moving towards the target. The soft robot that we modeled in the simulation is a robot that was being designed by other members within the CHARM lab termed the vine robot. This soft robot was capable of stretching and shrinking itself in size, moving around in a bendy, ‘snake-like’ manner, and had a gripper at the end of it that acted as an end-effector. We used Unity as the 3D-environment software to develop our simulation due to Unity’s reliable physics engine and its powerful inverse kinematics toolbox. In conclusion, MBSA was able to successfully establish shared-autonomy within the vine robot albeit with some issues regarding obstacle avoidance. However, this algorithm shows great promise for future work to be done within this subsection of human-robot interactions

The KnotLink Game

Recently, several new games have been introduced that can be played on knot and link diagrams. One of the first such games, played on knot diagrams, is called the Knotting-Unknotting Game. In this game, one player aims to create an unknot while their opponent tries to produce a nontrivial knot. The Linking-Unlinking Game is similar, but is played on link diagrams. In this game, one player's goal is to produce an unlink while the other player aims to create any nontrivial link. In our paper, we introduce a hybrid of these two games, called the KnotLink game, that can be played on either a knot or a link diagram. Moves and players' goals are similar to those of the previous two games, with one key difference that allows the game board to be transformed from a knot to a link or vice versa during game play. We describe this new game, provide a sample game, and prove several results regarding winning strategies for infinite families of rational knots and links

Effect of Brief Biofeedback via a Smartphone App on Stress Recovery: Randomized Experimental Study.

BACKGROUND:Smartphones are often vilified for negatively influencing well-being and contributing to stress. However, these devices may, in fact, be useful in times of stress and, in particular, aid in stress recovery. Mobile apps that deliver evidence-based techniques for stress reduction, such as heart rate variability biofeedback (HRVB) training, hold promise as convenient, accessible, and effective stress-reducing tools. Numerous mobile health apps that may potentially aid in stress recovery are available, but very few have demonstrated that they can influence health-related physiological stress parameters (eg, salivary biomarkers of stress). The ability to recover swiftly from stress and reduce physiological arousal is particularly important for long-term health, and thus, it is imperative that evidence is provided to demonstrate the effectiveness of stress-reducing mobile health apps in this context. OBJECTIVE:The purpose of this research was to investigate the physiological and psychological effects of using a smartphone app for HRVB training following a stressful experience. The efficacy of the gamified Breather component of the Happify mobile health app was examined in an experimental setting. METHODS:In this study, participants (N=140) underwent a laboratory stressor and were randomly assigned to recover in one of three ways: with no phone present, with a phone present, with the HRBV game. Those in the no phone condition had no access to their phone. Those in the phone present condition had their phone but did not use it. Those in the HRVB game condition used the serious game Breather on the Happify app. Stress recovery was assessed via repeated measures of salivary alpha amylase, cortisol, and self-reported acute stress (on a 1-100 scale). RESULTS:Participants in the HRVB game condition had significantly lower levels of salivary alpha amylase during recovery than participants in the other conditions (F2,133=3.78, P=.03). There were no significant differences among the conditions during recovery for salivary cortisol levels or self-reported stress. CONCLUSIONS:These results show that engaging in a brief HRVB training session on a smartphone reduces levels of salivary alpha amylase following a stressful experience, providing preliminary evidence for the effectiveness of Breather in improving physiological stress recovery. Given the known ties between stress recovery and future well-being, this study provides a possible mechanism by which gamified biofeedback apps may lead to better health

Stroke-related Effects on Maximal Dynamic Hip Flexor Fatigability and Functional Implications

Introduction: Stroke-related changes in maximal dynamic hip flexor muscle fatigability may be more relevant functionally than isometric hip flexor fatigability. Methods: Ten chronic stroke survivors performed 5 sets of 30 hip flexion maximal dynamic voluntary contractions (MDVC). A maximal isometric voluntary contraction (MIVC) was performed before and after completion of the dynamic contractions. Both the paretic and nonparetic legs were tested. Results: Reduction in hip flexion MDVC torque in the paretic leg (44.7%) was larger than the nonparetic leg (31.7%). The paretic leg had a larger reduction in rectus femoris EMG (28.9%) between the first and last set of MDVCs than the nonparetic leg (7.4%). Reduction in paretic leg MDVC torque was correlated with self-selected walking speed (r2 = 0.43), while reduction in MIVC torque was not (r2 = 0.11). Conclusions: Reductions in maximal dynamic torque of paretic hip flexors may be a better predictor of walking function than reductions in maximal isometric contractions

The Stroke-related Effects of Hip Flexion Fatigue on Over Ground Walking

Individuals post stroke often rely more on hip flexors for limb advancement during walking due to distal weakness but the effects of muscle fatigue in this group is not known. The purpose of this study was to quantify how stroke affects the influence of hip flexor fatigue on over ground walking kinematics and performance and muscle activation. Ten individuals with chronic stroke and 10 without stroke (controls) participated in the study. Maximal walking speed, walking distance, muscle electromyograms (EMG), and lower extremity joint kinematics were compared before and after dynamic, submaximal fatiguing contractions of the hip flexors (30% maximal load) performed until failure of the task. Task duration and decline in hip flexion maximal voluntary contraction (MVC) and power were used to assess fatigue. The stroke and control groups had similar task durations and percent reductions in MVC force following fatiguing contractions. Compared with controls, individuals with stroke had larger percent reductions in maximal walking speed, greater decrements in hip range of motion and peak velocity during swing, greater decrements in ankle velocity and lack of modulation of hip flexor EMG following fatiguing dynamic hip flexion contractions. For a given level of fatigue, the impact on walking function was more profound in individuals with stroke than neurologically intact individuals, and a decreased ability to up regulate hip flexor muscle activity may contribute. These data highlight the importance of monitoring the effect of hip flexor muscle activity during exercise or performance of activities of daily living on walking function post stroke