Outdoor Overground Gait Biomechanics and Energetics in Individuals With Transtibial Amputation Walking With a Prescribed Passive Prosthesis and a Bionic Myoelectric Prosthesis.

The metabolic cost of walking for individuals with transtibial amputation is generally greater compared with able-bodied individuals. One aim of powered prostheses is to reduce metabolic deficits by replicating biological ankle function. Individuals with transtibial amputation can activate their residual limb muscles to volitionally control bionic ankle prostheses for walking; however, it is unknown how myoelectric control performs outside the laboratory.

Soft tissue can absorb surprising amounts of energy during knee exoskeleton use.

Soft tissue at the human-exoskeleton interface can deform under load to absorb, return and dissipate the mechanical energy generated by the exoskeleton. These soft tissue effects are often not accounted for and may mislead researchers on the actual joint assistance an exoskeleton provides. We assessed the effects of soft tissue by quantifying the performance and energy distribution of a knee exoskeleton under different assistance strategies using a synthetic lower limb phantom.

Mobile brain-body imaging data set of indoor treadmill walking and outdoor walking with a visual search task.

To fully understand brain processes in the real world, it is necessary to record and quantitatively analyse brain processes during real world human experiences. Mobile electroencephalography (EEG) and physiological data sensors provide new opportunities for studying humans outside of the laboratory. The purpose of this study was to document data from high-density EEG and mobile physiological sensors while humans performed a visual search task both on a treadmill in a laboratory setting and overground in a natural outdoor setting.

Individual joint contributions to forward propulsion are not related to stability during walking in young or older adults.

Background: Older adults are less stable and walk slower than younger adults, both of which are associated with higher fall risk. Older adults use ankle musculature less and rely more on hip contributions for forward propulsion than younger adults, which has been suggested to be a protective walking strategy to increase stability. However, whether distal-to-proximal redistribution of propulsion and dynamic margin of stability are related has not been determined.

Effects of Stroboscopic Goggles on Standing Balance in the Spatiotemporal and Frequency Domains: An Exploratory Study.

Balance training paradigms have been shown to effectively reduce fall risk. Visual feedback is an important sensory mechanism for regulating postural control, promoting visual perturbations for balance training paradigms. Stroboscopic goggles, which oscillate from transparent to opaque, are a form of visual perturbation, but their effect on standing balance has not been assessed.

Vision Is Not Required to Elicit Balance Improvements From Beam Walking Practice.

Background: Beam walking is a highly studied assessment of walking balance. Recent research has demonstrated that brief intermittent visual rotations and occlusions can increase the efficacy of beam walking practice on subsequent beam walking without visual perturbations. We sought to examine the influence of full vision removal during practice walking on a treadmill-mounted balance beam.

Walking Ankle Biomechanics of Individuals With Transtibial Amputations Using a Prescribed Prosthesis and a Portable Bionic Prosthesis Under Myoelectric Control.

Individuals with transtibial amputation can activate residual limb muscles to volitionally control robotic ankle prostheses for walking and postural control. Most continuous myoelectric ankle prostheses have used a tethered, pneumatic device. The Open Source Leg allows for myoelectric control on an untethered electromechanically actuated ankle.

Exploring Electrocortical Signatures of Gait Adaptation: Differential Neural Dynamics in Slow and Fast Gait Adapters.

Individuals exhibit significant variability in their ability to adapt locomotor skills, with some adapting quickly and others more slowly. Differences in brain activity likely contribute to this variability, but direct neural evidence is lacking. We investigated individual differences in electrocortical activity that led to faster locomotor adaptation rates.

Electrocortical theta activity may reflect sensory prediction errors during adaptation to a gradual gait perturbation.

Locomotor adaptation to abrupt and gradual perturbations are likely driven by fundamentally different neural processes. The aim of this study was to quantify brain dynamics associated with gait adaptation to a gradually introduced gait perturbation, which typically results in smaller behavioral errors relative to an abrupt perturbation. Loss of balance during standing and walking elicits transient increases in midfrontal theta oscillations that have been shown to scale with perturbation intensity.

Resting state brain network segregation is associated with walking speed and working memory in older adults.

Older adults exhibit larger individual differences in walking ability and cognitive function than young adults. Characterizing intrinsic brain connectivity differences in older adults across a wide walking performance spectrum may provide insight into the mechanisms of functional decline in some older adults and resilience in others. Thus, the objectives of this study were to: (1) determine whether young adults and high- and low-functioning older adults show group differences in brain network segregation, and (2) determine whether network segregation is associated with working memory and walking function in these groups.

Prefrontal cortical activity during uneven terrain walking in younger and older adults.

Introduction: Walking in complex environments increases the cognitive demand of locomotor control; however, our understanding of the neural mechanisms contributing to walking on uneven terrain is limited. We used a novel method for altering terrain unevenness on a treadmill to investigate the association between terrain unevenness and cortical activity in the prefrontal cortex, a region known to be involved in various cognitive functions.

Methods: Prefrontal cortical activity was measured with functional near infrared spectroscopy while participants walked on a novel custom-made terrain treadmill surface across four different terrains: flat, low, medium, and high levels of unevenness.

Mobile neuroimaging: What we have learned about the neural control of human walking, with an emphasis on EEG-based research.

Our understanding of the neural control of human walking has changed significantly over the last twenty years and mobile brain imaging methods have contributed substantially to current knowledge. High-density electroencephalography (EEG) has the advantages of being lightweight and mobile while providing temporal resolution of brain changes within a gait cycle. Advances in EEG hardware and processing methods have led to a proliferation of research on the neural control of locomotion in neurologically intact adults.

Improving Maternal Health and Birth Outcomes Through FreshRx: A Food-Is-Medicine Intervention.

Purpose: Food insecurity has far-reaching consequences for health and well-being, especially during pregnancy and postpartum periods. This study examines a food-is-medicine approach that aimed to reduce food insecurity, maternal stress, depression, anxiety, preterm labor, and low birthweight.

Design: Pre-post interventional study of FreshRx: Nourishing Healthy Starts, a pregnancy focused food-is-medicine program led by a local hunger relief organization and obstetrics department.

A regulatory focus theory perspective on the dynamics between action and power.

Building on the strong consensus that the experience of power motivates individuals to take action, prior research postulates a positively reinforcing cycle wherein taking action leads to power, which in turn leads to subsequent actions. Applying regulatory focus theory, we differentiate between promotion-oriented and prevention-oriented actions to develop a within-person theory of when and why promotion-oriented and prevention-oriented actions should relate to power, and vice-versa. Across two studies, we find that when employees engaged in promotive voice behaviors, they were more likely to experience a sense of power; this effect was amplified for employees with trait promotion focus.

From humanitarian crisis to employment crisis: The lives and livelihoods of South Sudanese refugee health workers in Uganda.

Despite the many benefits of refugee health workers for health systems, they commonly face challenges integrating into host country workforces. The Global Code of Practice on International Recruitment of Health Personnel, which should monitor and protect migrant health workers, offers little guidance for refugees and research is needed to inform strategy. Based on interviews with 34 refugee health workers and 10 leaders across two settlements supporting populations fleeing the humanitarian crisis in South Sudan since 2013, we describe the governance and social dynamics affecting South Sudanese refugee health worker employment in Uganda.

Dual-layer electroencephalography data during real-world table tennis.

Real-world settings are necessary to improve the ecological validity of neuroscience research, and electroencephalography (EEG) facilitates mobile electrocortical recordings because of its easy portability and high temporal resolution. Table tennis is a whole-body, goal-directed sport that requires constant visuomotor feedback, anticipation, strategic decision-making, object interception, and performance monitoring - making it an interesting testbed for a variety of neuroscience studies. Although traditionally plagued by artifact contamination, recent advances in signal processing and hardware approaches, such as the dual-layer approach, have allowed high fidelity EEG recordings during whole-body maneuvers.

Neuromechanical Adaptation to Walking With Electromechanical Ankle Exoskeletons Under Proportional Myoelectric Control.

Objective: To determine if robotic ankle exoskeleton users decrease triceps surae muscle activity when using proportional myoelectric control, we studied healthy young participants walking with commercially available electromechanical ankle exoskeletons (Dephy Exoboot) with a novel controller. The vast majority of robotic lower limb exoskeletons do not have direct neural input from the user which makes adaptation of exoskeleton dynamics based on user intent difficult. Proportional myoelectric control has proven to allow considerable adaptation in muscle activation and gait kinematics in pneumatic, tethered ankle exoskeletons.

My manager endorsed my coworkers' voice: Understanding observers' positive and negative reactions to managerial endorsement of coworker voice.

Research on managerial voice endorsement has primarily focused on the processes and conditions through which voicers receive their managers' endorsement. We shift this focus away from the voicers, focusing instead on the dual reactions that endorsement generates for observing employees. Drawing from an approach-avoidance framework, we propose that managerial endorsement of coworker voice could be perceived as a positive and negative stimulus for observers, prompting them to approach opportunities and avoid threats, respectively.

When Who Matters: Interviewer Effects and Survey Modality.

When and how to survey potential respondents is often determined by budgetary and external constraints, but choice of survey modality may have enormous implications for data quality. Different survey modalities may be differentially susceptible to measurement error attributable to interviewer assignment, known as interviewer effects. In this paper, we leverage highly similar surveys, one conducted face-to-face (FTF) and the other via phone, to examine variation in interviewer effects across survey modality and question type.

A table tennis serve versus rally hit elicits differential hemispheric electrocortical power fluctuations.

Human visuomotor control requires coordinated interhemispheric interactions to exploit the brain's functional lateralization. In right-handed individuals, the left hemisphere (right arm) is better for dynamic control and the right hemisphere (left arm) is better for impedance control. Table tennis is a game that requires precise movements of the paddle, whole body coordination, and cognitive engagement, providing an ecologically valid way to study visuomotor integration.

Gait variability of outdoor vs treadmill walking with bilateral robotic ankle exoskeletons under proportional myoelectric control.

Lower limb robotic exoskeletons are often studied in the context of steady-state treadmill walking in laboratory environments. However, the end goal of these devices is often adoption into our everyday lives. To move outside of the laboratory, there is a need to study exoskeletons in real world, complex environments.

Individual differences in cooperative and competitive play strategies.

Introduction: Cooperation and competition are common in social interactions. It is not clear how individual differences in personality may predict performance strategies under these two contexts. We evaluated whether instructions to play cooperatively and competitively would differentially affect dyads playing a Pong video game.

iCanClean Removes Motion, Muscle, Eye, and Line-Noise Artifacts from Phantom EEG.

The goal of this study was to test a novel approach (iCanClean) to remove non-brain sources from scalp EEG data recorded in mobile conditions. We created an electrically conductive phantom head with 10 brain sources, 10 contaminating sources, scalp, and hair. We tested the ability of iCanClean to remove artifacts while preserving brain activity under six conditions: , , , , , and .