Weight Shift Research Articles

P20-052-23 The Gut Microbiome Tracks With Shifts in Body Weight During the Freshman Year of College in Dormitory-Housed Adolescents

P20-052-23 The Gut Microbiome Tracks With Shifts in Body Weight During the Freshman Year of College in Dormitory-Housed Adolescents

Cortical facilitation of tactile afferents during the preparation of a body weight transfer when standing on a biomimetic surface.

Self-generated movement shapes tactile perception, but few studies have investigated the brain mechanisms involved in the processing of the mechanical signals related to the static and transient skin deformations generated by forces and pressures exerted between the foot skin and the standing surface. We recently found that standing on a biomimetic surface (i.e., inspired by the characteristics of mechanoreceptors and skin dermatoglyphics), that magnified skin-surface interaction, increased the sensory flow to the somatosensory cortex and improved balance control compared to standing on control (e.g., smooth) surfaces. In this study, we tested whether the well-known sensory suppression that occurs during movements is alleviated when the tactile afferent signal becomes relevant with the use of a biomimetic surface. Eyes-closed participants (n = 25) self-stimulated their foot cutaneous receptors by shifting their body weight toward one of their legs while standing on either a biomimetic or a control (smooth) surface. In a control task, similar forces were exerted on the surfaces (i.e., similar skin-surface interaction) by passive translations of the surfaces. Sensory gating was assessed by measuring the amplitude of the somatosensory-evoked potential over the vertex (SEP, recorded by EEG). Significantly larger and shorter SEPs were found when participants stood on the biomimetic surface. This was observed whether the forces exerted on the surface were self-generated or passively generated. Contrary to our prediction, we found that the sensory attenuation related to the self-generated movement did not significantly differ between the biomimetic and control surfaces. However, we observed an increase in gamma activity (30-50 Hz) over centroparietal regions during the preparation phase of the weight shift only when participants stood on the biomimetic surface. This result might suggest that gamma-band oscillations play an important functional role in processing behaviorally relevant stimuli during the early stages of body weight transfer.

The usability of two mobile health assistive technologies for wheelchair-related in-seat movement and pressure.

This study aimed to understand the degree to which two different mobile health assistive technologies, AW-Shift© and Sensoria® Mat, addressed seven constructs for managing wheelchair-related in-seat movement and pressure. After using each intervention system, participants answered questions regarding the general usability and usefulness of the systems. System Usability Survey scores ranged from 5 (Poor) to 97.5 (Excellent), with a median response of 60.0 (Okay) for AW-Shift© and 76.3 (Good) for Sensoria® Mat. Participants reported using AW-Shift© to check areas of high pressure on their cushion, the quality of their weight shifts, and their posture significantly more often than to check the condition of their cushion or to track their movement goals. Participants reported using Sensoria® Mat to check the quality and number of weight shifts, and their posture significantly more often than to check the condition of their cushion. The findings of this study highlight that there is no one-size-fits-all solution and that different subpopulations of wheelchair users may have different needs and preferences. Optimizing the design for specific cohorts or constructs can result in an effective product that consistently provides meaningful and accurate information about behavior and performance.

Geodesic length and shifted weights in first-passage percolation

We study first-passage percolation through related optimization problems over paths of restricted length. The path length variable is in duality with a shift of the weights. This puts into a convex duality framework old observations about the convergence of the normalized Euclidean length of geodesics due to Hammersley and Welsh, Smythe and Wierman, and Kesten, and leads to new results about geodesic length and the regularity of the shape function as a function of the weight shift. For points far enough away from the origin, the ratio of the geodesic length and the ℓ 1 \ell ^1 distance to the endpoint is uniformly bounded away from one. The shape function is a strictly concave function of the weight shift. Atoms of the weight distribution generate singularities, that is, points of nondifferentiability, in this function. We generalize to all distributions, directions and dimensions an old singularity result of Steele and Zhang for the planar Bernoulli case. When the weight distribution has two or more atoms, a dense set of shifts produces singularities. The results come from a combination of the convex duality, the shape theorems of the different first-passage optimization problems, and modification arguments.

Overground walking with a constraint force on the nonparetic leg during swing improves weight shift toward the paretic side in people after stroke.

Targeting enhancing the use of the paretic leg during locomotor practice might improve motor function of the paretic leg. The purpose of this study was to determine whether application of constraint force to the nonparetic leg in the posterior direction during overground walking would enhance the use of the paretic leg in people with chronic stroke. Fifteen individuals after stroke participated in two experimental conditions, i.e., overground walking with a constraint force applied to the nonparetic leg and overground walking only. Each participant was tested in the following procedures that consisted of overground walking with either constraint force or no constraint force, instrumented split-belt treadmill walking, and pressure-sensitive gait mat walking before and after the overground walking. Overground walking practice with constraint force resulted in greater enhancement in lateral weight shift toward the paretic side (P < 0.01), muscle activity of the paretic hip abductors (P = 0.04), and propulsion force of the paretic leg (P = 0.05) compared with the results of the no-constraint condition. Overground walking practice with constraint force tended to induce greater increase in self-selected overground walking speed (P = 0.06) compared with the effect of the no-constraint condition. The increase in propulsion force from the paretic leg was positively correlated with the increase in self-selected walking speed (r = 0.6, P = 0.03). Overground walking with constraint force applied to the nonparetic leg during swing phase of gait may enhance use of the paretic leg, improve weight shifting toward the paretic side and propulsion of the paretic leg, and consequently increase walking speed.NEW & NOTEWORTHY Application of constraint force to the nonparetic leg during overground walking induced improved lateral weight shifts toward the paretic leg and enhanced muscle activity of the paretic leg during walking. In addition, one session of overground walking with constraint force might induce an increase in propulsive force of the paretic leg and an increase in self-selected overground walking speed, which might be partially due to the improvement in motor control of the paretic leg.

Reducing pressure with the goal of improving outcomes: a retrospective chart review of cushion evaluations and recommendations at one seating clinic

Purpose To describe the current seating recommendations made by a seating clinic for wheelchair users who presented with a Pressure Injury (PrI) or history of PrI. Methods Retrospective review of electronic medical records of 133 adults who used a wheelchair as their primary means of mobility who had a cushion evaluation during which interface pressure mapping data was documented. Results Clinicians adjusted 71% of participants’ wheelchair cushions, including 49% who received a new cushion, and 37% of participants’ wheelchairs. The most common adjustments besides receiving a new cushion were: addition of an underlay, adjusting the inflation of a cushion, and adjustments to the foot or back support of the wheelchair. Forty-five participants only received adjustments (i.e. no new cushion), while 23 participants only received education and feedback rather than equipment modifications. Those 23 participants had significantly lower Peak Pressure Index (PPI) than those who received equipment modifications (mean [95% CI] 76.7 [59.1, 94.3] versus 111.6 [102.1, 121.2] respectively, p = 0.001). The PPI was reduced by an average of 22.5 mmHg from the initial to final seating system amongst those who received modifications ([13.9–31.0], p<.001). Conclusions The seating clinicians considered interface pressure mapping in their decision-making and effectively reduced interface pressures with their interventions. Cushion replacement is important when someone presents with a PrI. However, adjusting an existing wheelchair cushion and/or seating system provides important additions and alternatives to consider for reducing interface pressure. There is also a role for education about proper use of equipment, weight shifts, and alternate seating surfaces. IMPLICATIONS FOR REHABILITATION A cushion evaluation may involve evaluating more than one cushion configuration and using pressure mapping to compare the best options. To address perceived wheelchair cushion issues, posture and positioning should be evaluated and adjusted as necessary, in addition to evaluating the cushion itself. Common positioning modifications include: modifying/adding cushion underlays or inflation and foot and back supports in response to clients’ changing postural needs and wheelchair components coming out of optimal position due to wear and tear. Adjustments to the wheelchair and cushion aim to distribute body weight over a larger surface area, reduce pressure at high-risk locations, improve posture, and increase function. These adjustments should consider individual’s specific needs and goals, while also being mindful of funding barriers.

Clinical practice recommendations for management of lateropulsion after stroke determined by a Delphi expert panel

Objective People exhibiting post-stroke lateropulsion actively push their body across the midline to the more affected side and/or resist weight shift toward the less affected side. Despite its prevalence and associated negative rehabilitation outcomes, no clinical practice guidelines exist for the rehabilitation of post-stroke lateropulsion. We aimed to develop consensus-based clinical practice recommendations for managing post-stroke lateropulsion using an international expert panel. Design This Delphi panel process conformed with Guidance on Conducting and Reporting Delphi Studies recommendations. Participants Panel members had demonstrated clinical and/or scientific background in the rehabilitation of people with post-stroke lateropulsion. Main Measures The process consisted of four electronic survey rounds. Round One consisted of 13 open questions. Subsequent rounds ascertained levels of agreement with statements derived from Round One. Consensus was defined a priori as ≥75% agreement (agree or strongly agree), or ≥70% agreement after excluding ‘unsure’ responses. Results Twenty participants completed all four rounds. Consensus was achieved regarding a total of 119 recommendations for rehabilitation approaches and considerations for rehabilitation delivery, positioning, managing fear of falling and fatigue, optimal therapy dose, and discharge planning. Statements for which ‘some agreement’ (50%–74% agreement) was achieved and those for which recommendations remain to be clarified were recorded. Conclusions These recommendations build on existing evidence to guide the selection of interventions for post-stroke lateropulsion. Future research is required to elaborate specific rehabilitation strategies, consider the impact of additional cognitive and perceptual impairments, describe positioning options, and detail optimal therapy dose for people with lateropulsion.

Narrowing the analytical gap for water-soluble polymers: A novel trace-analytical method and first quantitative occurrence data for polyethylene oxide in surface and wastewater

Water-soluble polymers (WSPs) like polyethylene oxide (PEO) have annual production volumes ranging from thousands to millions of tonnes and are used in a wide variety of applications that enable a release into the aquatic environment. Despite these facts, a lack of quantitative trace-analytical methods for WSPs prevents the comprehensive study of their environmental occurrence. Here, size exclusion chromatography was hyphenated with electrospray ionization high-resolution mass spectrometry. An all-ion fragmentation approach for the formation of diagnostic fragments independent of molecular weight, charge state, and ion species was used to quantify PEO and its derivatives in wastewater treatment plants (WWTPs) and surface water samples. Despite its inherent biodegradability, PEO concentrations found in the samples analysed ranged from <LOD-11 μg/L for surface waters (11/18 samples >1 μg/L) and reached up to 20 μg/L (effluent) and 400 μg/L (influent) for WWTPs. A substantial shift in molecular weight ranges was observed between influent and effluent, pointing towards a molecular weight fraction between 1.3 and 4 kDa being dominant in the effluent. Due to an assumed size exclusion during sample enrichment, information on the MW-distribution of PEO is limited to MW < 55 kDa. The high concentrations widely detected for a readily biodegradable WSP such as PEO, raise strong concerns about the occurrence and fate of recalcitrant WSPs in the aquatic environment. The method presented herein may provide the tools necessary to assess the burden of these high production volume chemicals and the risk they may pose.

The Noonday argument: fine-graining, indexicals, and the nature of Copernican reasoning

AbstractTypicality arguments attempt to use the Copernican Principle to draw conclusions about the cosmos and presently unknown conscious beings within it, including extraterrestrial intelligences (ETI). The most notorious is the Doomsday Argument, which purports to constrain humanity's future from its current lifespan alone. These arguments rest on a likelihood calculation that penalizes models in proportion to the number of distinguishable observers. I argue that such reasoning leads to solipsism, the belief that one is the only being in the world, and is therefore unacceptable. Using variants of the ‘Sleeping Beauty’ thought experiment as a guide, I present a framework for evaluating observations in a large cosmos: Weighted Fine Graining (WFG). WFG requires the construction of specific models of physical outcomes and observations. Valid typicality arguments then emerge from the combinatorial properties of third-person physical microhypotheses. Indexical (observer-relative) facts do not directly constrain physical theories, but instead weight different provisional evaluations of credence. As indexical knowledge changes, the weights shift. I show that the self-applied Doomsday Argument fails in WFG, even though it can work for an external observer. I argue that the Copernican Principle does not let us apply self-observations to constrain ETIs.

Beyond step counts: Including wear time in prosthesis use assessment for lower-limb amputation.

The purpose of this study was to test a novel activity monitor that tracks the time a prosthesis is worn, and the nature of the ambulatory activity conducted with the prosthesis. These capabilities allow prosthesis users' wear and accommodation practices (e.g., temporary doffing) to be monitored, and the intensity of their activities to be assessed. A portable limb-socket motion sensing system was used to monitor doffs, walk bouts (≥5 steps), low locomotion (2-4 steps), stationary positions, and weight shifts in a group of transtibial prosthesis users. The relationship between doff time and active motion time was investigated, and durations of low and high intensity active motions were compared. For the 14 participants tested, the median prosthesis day duration ranged from 12.8-18.8h. Eleven participants typically doffed five or fewer times per day, and three participants typically doffed 10 or more times per day. Nine participants demonstrated a positive correlation between daily doff duration and active motion duration. Six participants spent more time in weight shifts than walk bouts, while eight participants spent more time in walk bouts than weight shifts. Capturing don time and temporary doffs and distinguishing weight shifts from walks may provide insight relevant to patient care. Longer-term monitoring studies should be conducted, and the clinical utility of the data evaluated.

Biomechanical Response Following Compelled Forward Weight Shift in Old Versus Young Adults

Biomechanical Response Following Compelled Forward Weight Shift in Old Versus Young Adults

Customized gaming system engages young children in reaching and balance training.

Trunk stability, an important prerequisite for many activities of daily living, can be impaired in children with movement disorders. Current treatment options can be costly and fail to fully engage young participants. We developed an affordable, smart screen-based intervention and tested if it engages young children in physical therapy goal driven exercises. Here we describe the ADAPT system, Aiding Distanced and Accessible Physical Therapy, which is a large touch-interactive device with customizable games. One such game, "Bubble Popper," encourages high repetitions of weight shifts, reaching, and balance training as the participant pops bubbles in sitting, kneeling, or standing positions. Sixteen participants aged 2-18years were tested during physical therapy sessions. The number of screen touches and length of game play indicate high participant engagement. In trials lasting less than 3min, on average, older participants (12-18years) made 159 screen touches per trial while the younger participants (2-7years) made 97. In a 30-min session, on average, older participants actively played the game for 12.49min while younger participants played for 11.22min. The ADAPT system is a feasible means to engage young participants in reaching and balance training during physical therapy.

Enhanced phasic sensory afferents paired with controlled constraint force improve weight shift toward the paretic side in individuals post-stroke

PurposeThe goal of this study was to determine whether enhanced phasic sensory afferent input paired with the application of controlled constraint force during walking would improve weight shift toward the paretic side and enhance use of the paretic leg. MethodsFourteen stroke survivors participated in two experimental conditions, sessions that consisted of 1 min treadmill walking without force and stimulation (baseline), 7 min walking with either “constraint force and sensory stimulation (constraint+stim)” or “constraint force only (constraint)” (adaptation), and then 2 min walking without force and stimulation (post-adaptation). Kinematics of the pelvis and legs, and muscle activity of the paretic leg were recorded. ResultsParticipants showed greater increases in hip abductor (p < 0.001) and adductor (p = 0.04) muscle activities, weight shift toward the paretic side (p = 0.002), and step length symmetry (p < 0.01) during the late post-adaptation period in the “constraint+stim” condition, compared with the effect of the “constraint” condition. In addition, changes in overground walking speed from baseline to 10 min post treadmill walking was significantly greater for the “constraint force and stimulation” condition than for the “constraint force only” condition (p = 0.04). ConclusionEnhanced targeted sensory afferent input during locomotor training may facilitate recruitment of targeted muscles of the paretic leg and facilitate use-dependent motor learning of locomotor tasks, which might retain longer and partially transfer from treadmill to overground walking, in stroke survivors.

Neutron scattering study of fluctuating and static spin correlations in the anisotropic spin glass Fe2TiO5

The anisotropic spin-glass transition, in which spin freezing is observed only along the $c$ axis in pseudobrookite ${\mathrm{Fe}}_{2}\mathrm{Ti}{\mathrm{O}}_{5}$, has long been perplexing because the ${\mathrm{Fe}}^{3+}$ moments $({d}^{5})$ are expected to be isotropic. Recently, neutron diffraction demonstrated that surfboard-shaped antiferromagnetic nanoregions coalesce above the glass transition temperature ${T}_{g}\ensuremath{\approx}55\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, and a model was proposed in which the freezing of the surfboard magnetization fluctuations leads to the anisotropic spin-glass state. Given this model, we have carried out high-resolution inelastic neutron scattering measurements of the spin-spin correlations to understand the temperature dependence of the intrasurfboard spin dynamics on neutron (picosecond) timescales. Here, we report on the temperature-dependence of the spin fluctuations measured from single-crystal ${\mathrm{Fe}}_{2}\mathrm{Ti}{\mathrm{O}}_{5}$. Strong quasi-elastic magnetic scattering, arising from intrasurfboard correlations, is observed well above ${T}_{g}$. The spin fluctuations possess a steep energy--wave vector relation and are indicative of strong exchange interactions, consistent with the large Curie-Weiss temperature. As the temperature approaches ${T}_{g}$ from above, a shift in spectral weight from inelastic to elastic scattering is observed. At various temperatures between 4 and 300 K, a characteristic relaxation rate of the fluctuations is determined. Despite the freezing of most of the spin correlations, an inelastic contribution remains even at base temperature, signifying the presence of fluctuating intrasurfboard spin correlations to at least $T/{T}_{g}\ensuremath{\approx}0.1$, consistent with an energy landscape that is a hybrid between conventional and geometrically frustrated spin glasses.

Design and Control of a Size-Adjustable Pediatric Lower-Limb Exoskeleton Based on Weight Shift

Lower-limb exoskeletons have been proven to be beneficial for motor function disability patients, in both clinical rehabilitation settings and daily activities. However, exoskeletons for the pediatric field are still very limited. In this paper, a novel lower-limb exoskeleton design for children is presented. Based on the anthropometric data of the target group, the size of the exoskeleton is designed adjustable to suit children from 8 to 12 years old. It employs six active joints on the knee and hip, actuated by Brushless DC motors and Harmonic Drive gears. The controller is based on a finite state machine model and the weight shift between two feet to generate the gait trajectory. An innovative automatic step-triggering mechanism is also proposed, based on the feedback from the ground reaction force sensor on the foot. Two user interfaces on the exoskeleton and the host PC are designed for easily operating the exoskeleton by clinicians and engineers. Experiments have been conducted with three healthy volunteers following the predesigned rehabilitation session protocol. Results show that the exoskeleton can well follow the gait trajectory generated by the control algorithm. All volunteers can fulfill all tasks in the test protocol with reduced efforts and the steps are automatically triggered by the presented controller.

Physiotherapy skills in the difference of years of therapists’ experience and affiliations

In Japan, a physiotherapist is considered to be ‘experienced’ and having sufficient time in the field, regardless of their level, efficacy, or quality of training, after five years of practice. However, this definition is insufficient for establishing quality and uniformity among physiotherapists in Japan. The purpose of this study was to establish the groundwork for standardisation in education and evaluation. It aimed to evaluate physiotherapy skills by means of a Weight Shift (WS) practical assessment task. Participants of this study included 10 physiotherapists from two institutions. The WS task was repeated three times on a simulated patient. The ground reaction force (GRF) of the simulated patient was recorded during the task. The ratio of the centre of pressure (COP) displacement was calculated by dividing the COP displacement by the distance between the centre of pressure of both feet of the simulated patient to normalise. Correlational statistical analysis was used to confirm whether years of experience changes the degree of WS. The obtained data was compared between the institutions of therapists. The results of this study confirm that the correlation between the data obtained and years of therapists’ experience is weak or absent. There were significant differences between each institution’s ratios for COP displacement as well as for the maximum GRF. It was considered that years of therapists’ experience does not necessarily correlate with physiotherapy skill, especially if participants had six or more years of experience. Greater differences were observed between institutions with regards to the characteristics of physiotherapy skill.

Shift in Weight

Shift in Weight

COVID-19 IN THE MENA REGION: AN UPDATE

This manuscript is an updated version of a previous study that discusses the status of COVID-19 in the Middle East and North Africa (MENA). It aims to analyze the change in COVID-19 caseload and outcome, as well as the progress in vaccination programs in the region. It dissects factors contributing to the asymmetrical distribution of the disease. Data was recovered from the World Health Organization, COVID-19 Weekly Epidemiological Update, Our World in Data organization, and the detailed reports issued by the ministry of health of each country. Information gathered included new cases, cumulative cases, and cumulative deaths, in addition to the total vaccine doses administered and population size of each country. PubMed and Medline were also surfed for relevant studies. The numbers correspond to the data between January 29, 2020, and November 17, 2021. The MENA region reported 15,351,715 cases and 272,428 deaths accounting for 6.1% and 5.31% of the global numbers respectively. Iran reserved the highest number of cases and deaths in the region despite achieving 50% fully vaccinated community. Iraq moved to the second rank in terms of caseload (2,070,883 cases), while Saudi Arabi had remarkable downward shift in disease weight. Lebanon and Egypt lost control over the pandemic. Syria, Yemen, and Libya have recorded near to the ground vaccination proportions. Case fatality rate ranged between 0.25%-19.39%. This region exhibits significant inequality in the pandemic trend secondary to wide variation in political, economic, social and medical solidity among the countries.

Structure-activity relationship of antioxidant polysaccharides from Salvia miltiorrhiza based on multiple fingerprint profiles and chemometrics analysis

The polysaccharides of Salvia miltiorrhiza (SMP) from 10 different sources were obtained by water extraction and alcohol precipitation, and their physicochemical properties and structures were analyzed. Multidimensional fingerprints based on high-performance liquid chromatography (HPLC), high-performance gel permeation chromatography (HPGPC) and proton nuclear magnetic resonance (1H-NMR) were established, and monosaccharide composition (galactose, glucose), molecular weight (SP1 2.07 × 106 Da-5.57 × 106 Da, SP3 692.20 Da–707.22 Da) and chemical shift (δ2 4.982 ppm, δ4 5.317 ppm) could be used for the quality control of SMP. The antioxidant activity was evaluated, and the spectrum effect relationship was studied. Galactose in the monosaccharide composition and the 2.07 × 106 Da-5.57 × 106 Da component in molecular weight were found to have a positive correlation effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, which can provide a preliminary basis and data reference for the quality control and structure-activity relationship study of SMP.

Potential biomechanical risk factors on developing lead knee osteoarthritis in the golf swing

The load on the lead knee joint during a golf swing is greater than that observed during gait. However, current evidence regarding golf swing biomechanics for risks associated with knee osteoarthritis (OA) is limited. Therefore, this study investigated golf swing styles associated with knee adduction and abduction moments, which are considered to be crucial loading regions of the medial and lateral compartments of knee OA, respectively. Thirteen professional male golfers performed five shots using a 5-iron club, and their swings were recorded using a motion capture system with two force platforms for the feet. A regression analysis was performed to calculate the correlation coefficients between the peak knee adduction and abduction moments of the lead leg and varus/valgus angle, toe-out angle, stance width, weight transfer, and shoulder sway. Swinging with a narrower stance width at address (r = − 0.62, p = 0.02) with more weight shift (r = 0.66, p = 0.014) and shoulder sway (r = 0.79, p = 0.001) towards the target during the downswing were associated with a higher peak knee adduction of the lead leg, whereas a greater valgus angle at address (r = 0.60, p = 0.03) was associated with a higher peak knee abduction of the lead leg. Based on these findings, we anticipate future research to support postural changes, particularly a wider stance width and restricted shoulder sway for golfers who are classified to be at high risk of developing medial compartment knee OA, as well as a lower valgus (tibial medial tilt) angle at address for those classified to be at high risk of developing lateral compartment knee OA.