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We investigated the impact of nutrient intake on hydration biomarkers in cyclists before and after a 161 km ride, including one hour after a 650 mL water bolus consumed post-ride. To control for multicollinearity, we chose a clustering-based, machine learning statistical approach. Five hydration biomarkers (urine color, urine specific gravity, plasma osmolality, plasma copeptin, and body mass change) were configured as raw- and percent change. Linear regressions were used to test for associations between hydration markers and eight predictor terms derived from 19 nutrients merged into a reduced-dimensionality dataset through serial k-means clustering. Most predictor groups showed significant association with at least one hydration biomarker: 1) Glycemic Load + Carbohydrates + Sodium, 2) Protein + Fat + Zinc, 3) Magnesium + Calcium, 4) Pinitol, 5) Caffeine, 6) Fiber + Betaine, and 7) Water, potassium + three polyols, and mannitol + sorbitol showed no significant associations with any hydration biomarker. All five hydration biomarkers were associated with at least one nutrient predictor in at least one configuration. We conclude that in a real-life scenario, some nutrients may serve as mediators of body water, and urine-specific hydration biomarkers may be more responsive to nutrient intake than measures derived from plasma or body mass.

Research has shown that the transition to parenthood is a particularly challenging period of life which is often associated with a decline in relationship quality and an increase in mental health problems. Emerging parents often experience difficulties in coping with new tasks and challenges in the relationship, resulting in inadequate mutual support, stress, conflicts and even depressive symptoms. To support expectant parents in establishing an effective and strong coparenting alliance, we have employed an educational coparenting intervention to teach important coparenting skills. The intervention was a non-randomized case-control study with 126 expectant parents. The intervention group participated in a five-session intervention, whereas the control group received an information booklet and had an optional meeting postpartum. The purpose of this study was to ease the transition to parenthood in order to prevent postpartum conflict and depression. Parents in the intervention group (n = 34 couples) showed significantly fewer conflicts postpartum than before (Z = -3.28, p = 0.00), and scored better in postnatal delegated dyadic coping (β = 0.25, p = 0.00, R2 = 0.32), a form of mutual support. Neither the intervention group (Z = -0.83, p = 0.40) nor the control group (Z = -0.86, p = 0.38) showed a significant increase in depression scores after childbirth. Although conflicts during the transition to parenthood declined and postnatal delegated dyadic coping strengthened, the study design does not allow to draw conclusion on group effects. Nevertheless, the promising results of this pilot intervention are a base for future studies.

Although trunk muscles extend across multiple vertebral joints, recent motor control studies have shown that a top-down progression of trunk control in typical infants occurs incrementally, one segment at a time, until independent sitting. The current study merges this surprising developmental pattern with parent behavior by exploring the relationship between how parents hold their infant and the segmental level for which the infant exhibits postural control. We measured trunk control of sixty infants (1–8 months) via the Segmental Assessment of Trunk Control. Spontaneous parental hold and variability was recorded during repeated sitting and standing conditions. Parent hold correlated with infant level of control in both sitting and standing, providing evidence for a positive interaction between parent behavior and segmental trunk development.

Wearable activity monitors are increasingly prevalent in health research, but there is as yet no data-driven study of artefact removal in datasets collected from typically developing children across childhood. Here, stride count data were collected via a commercially available activity monitor (StepWatch), which employs an internal filter for sub-threshold accelerations, but does not post-process supra-threshold activity data. We observed 428 typically-developing children, ages 2-15, wearing the StepWatch for 5 consecutive days. We developed a minimum per-minute stride-count below which the data outputted from the StepWatch could be considered 'idle' and not 'productive'. We found that a threshold stride count of 10 steps per minute captured 90% of samples in a weighted average among isolated non-zero stride-count samples offset by inactivity. This threshold did not vary by age, gender, or by an age-gender interaction. Filtering the activity data according to this threshold reduced overall stride count by 8-10% by age group, from 8177 ± 2659 to 7432 ± 2641 strides per day. The impact on number of bouts per day decreased from an overall average of 79.3 ± 17.2 to 72.7 ± 12.1; this effect varied by age group. This study delivers the first data-driven estimate of a minimum activity threshold in step- or stride units that may extend to other studies. We conclude that the impact of production-idle filtering on activity data is substantial and suggests a possible impetus for re-contextualizing extant studies and guidelines reported without such filtering.

To assess the efficacy of an off-loading wheelchair seat cushion in removing pressure from high-risk ischial tuberosities and the coccyx/sacrum in wheelchair sitting.Repeated-measures design.Private research laboratory.Manual wheelchair users with chronic spinal cord injuries (N=10).Three configurations of an off-loading wheelchair seat cushion compared with a flotation style (10-cm air inflation) wheelchair seat cushion.Outcome measures included peak pressure index (PPI), ischial tuberosity peak pressures, and the dispersion index or ratio of pressures under the ischial and sacral regions to the total of all pressures recorded.PPI and ischial tuberosities peak pressure ranged from a low of 39±18 and 68±46mmHg in the fully off-loaded cushion to a high of 97±30 and 106±34mmHg, respectively, for the flotation style cushion (2-way analysis of variance main effect across 4 conditions, P.001). Dispersion index ranged from a low of 8%±3% in the fully off-loaded cushion to a high of 16%±3% in the flotation style cushion. Pairwise comparisons yielded significance in all cushion-pair analyses (P.05 after multiple corrections).The force-removal approach of this orthotic off-loading cushion design effectively reduces a known extrinsic risk factor for pressure ulcers-interface pressure-in the high-risk ischial tuberosity and sacral/coccygeal regions of the buttocks.

Previous work focusing on understanding nutrient intake and its association with total body water homeostasis neglects to consider the collinearity of types of nutrients consumed and subsequent associations with hydration biomarkers. Therefore, the purpose of this study was to analyze consumption patterns of 23 a priori selected nutrients involved in osmotic homeostasis, as well as their association with 24 h urinary hydration markers among fifty African&ndash, American first-year college students through a repeated measures observation in a daily living setting. Through application of hierarchical clustering, we were able to identity four clusters of nutrients based on 24 h dietary recalls: (1) alcohol + pinitol, (2) water + calcium + magnesium + erythritol + inositol + sorbitol + xylitol, (3) total calories + total fat + total protein + potassium + sodium + zinc + phosphorous + arginine, and (4) total carbohydrates + total fiber + soluble fiber + insoluble fiber + mannitol + betaine. Furthermore, we found that consumption of nutrients in Cluster #2 was significantly predictive of urine osmolality (p = 0.004), no other clusters showed statistically significant associations with 24 h urinary hydration biomarkers. We conclude that there may be some nutrients that are commonly consumed concomitantly (at the day level), across a variety of settings and populations, and that a limited subset of the clustering of these nutrients may associate with body water status.

The incidence and etiology of prosthetic services utilization is poorly understood during the first 90 days post-delivery of the initial lower limb prosthesis. This period is of critical importance, as prevailing policy dictates limits on the reimbursement for certain services provided during this time period. The first step in understanding the financial ramifications of such policy is to examine the taxonomy behind clinical encounters during this tenuous time period.Quantify and categorize clinical encounters by incidence and etiology.Retrospective chart review.A central database containing data on prosthetic services was examined. Incidence and etiology were extracted through independent review of each patient chart.A total of 537 unique patients were identified, with 109 meeting the inclusion criteria. Chi-square testing showed that comfort ( p0.05), cosmesis ( p0.01), and mechanical failure ( p0.001) yielded statistical significance in scheduled versus unscheduled visits. Stepwise regression analysis demonstrated that both sex and K-level were important predictors of unscheduled visits.Taxonomization of clinical encounters experienced during the first 90 days provides a framework for future studies to be conducted. The data provided can serve as a basis for informing reimbursement policy, workforce planning, and advocacy. Clinical relevance Comfort is the most frequent reason for a clinical encounter during the first 90 days after delivering a lower limb prosthesis. The data on the taxonomy behind the clinical encounters can be used to guide workforce planning and advocate for just reimbursement policy that better reflect patient's needs.

Bed positioning poses a subtle, yet important, tradeoff in the competing needs of hospitalized patients, particularly those susceptible to lower respiratory tract infections and/or pressure ulcers. Although it is widely held that a minimum 30° incline is necessary to mitigate risk of ventilator-acquired pneumonia, it is unclear what effect semirecumbent positioning has on the risk of pressure ulcerations. The authors test several hypotheses with the objective of elucidating the relationship between bed incline, posture, and incline, pursuant to a more evidence-based recommendation for practice in clinical care. To this end, interfacial pressures from 40 healthy subjects were analyzed following observation in both supine and sidelying positions, at shallow (30°) and moderate (45°) bed-angle incline. Summarily, the authors report that supine postures reduce pressure signatures associated with pressure ulceration versus sidelying position: 15% increase area of contact (P = 1.3×10), and 17% decrease in ratio of peak to average pressure (P = 3.1×10). Within supine posture, the authors found significant increases in 4 measures of local pressure, including average pressure (10.4% decrease, P = .005) and coefficient of pressure variation (22.1%, P = 2.2×10) at moderate incline. The authors conclude that supine bed positionings at moderate incline appear to reduce predictors of pressure ulceration.

Background. While recent clinical trials involving robot-assisted therapy have failed to show clinically significant improvement versus conventional therapy, it is possible that a broader strategy of intensive therapy—to include robot-assisted rehabilitation—may yield clinically meaningful outcomes. Objective. To test the immediate and sustained effects of intensive therapy (robot-assisted therapy plus intensive conventional therapy) on outcomes in a chronic stroke population. Methods. A multivariate mixed-effects model adjusted for important covariates was established to measure the effect of intensive therapy versus usual care. A total of 127 chronic stroke patients from 4 Veterans Affairs medical centers were randomized to either robot-assisted therapy (n = 49), intensive comparison therapy (n = 50), or usual care (n = 28), in the VA-ROBOTICS randomized clinical trial. Patients were at least 6 months poststroke, of moderate-to-severe upper limb impairment. The primary outcome measure was the Fugl-Meyer Assessment at 12 and 36 weeks. Results. There was significant benefit of intensive therapy over usual care on the Fugl-Meyer Assessment at 12 weeks with a mean difference of 4.0 points (95% CI = 1.3-6.7); P = .005; however, by 36 weeks, the benefit was attenuated (mean difference 3.4; 95% CI = −0.02 to 6.9; P = .05). Subgroup analyses showed significant interactions between treatment and age, treatment and time since stroke. Conclusions. Motor benefits from intensive therapy compared with usual care were observed at 12 and 36 weeks posttherapy; however, this difference was attenuated at 36 weeks. Subgroups analysis showed that younger age, and a shorter time since stroke were associated with greater immediate and long-term improvement of motor function.

The Academy of Pediatric Physical Therapy Research Summit IV issued a Call to Action for community-wide intensification of a research enterprise in inquiries related to pediatric brain injury and motor disability by way of technological integration. But the barriers can seem high, and the pathways to integrative clinical research can seem poorly marked. Here, we answer the Call by providing framework to 3 objectives: (1) instrumentation, (2) biometrics and study design, and (3) data analytics. We identify emergent cases where this Call has been answered and advocate for others to echo the Call both in highly visible physical therapy venues and in forums where the audience is diverse.

Pressure mapping is a frequently used tool with great power to provide information about the forces between a patient and a wheelchair seat. One widely recognized limitation to this paradigm is the possibility of data loss due to sensor saturation. In this study, we seek to quantify and describe the saturation observed in the measurement of interface pressures of wheelchair users. We recorded approximately two minutes of interface pressure data from 22 elderly wheelchair users (11M/11F, 80 ± 10 years) and found that 4.7% of data frames had 1 saturated sensor, and 9.0% had more than one saturated sensor, for a total of 13.7% of all frames of data. Data from three of the 22 subjects (13.6%) were substantially affected by the persistent presence of saturated sensors. We conclude that for this population of elderly wheelchair users, sensor saturation may be a concern and should be factored properly into study design a priori.

Understanding interactions between cognitive and motor performance is an important theoretical and practical aim of motor neuroscience. Toward this aim, we invited university students to move one hand back and forth at a self-paced rate either in silence or while overtly generating words from semantic categories. The same participants also generated words without movement. Word generation affected manual performance but manual performance did not affect word generation. Only the timing, but not the spatial features, of the hand movements were influenced by word generation. The simplicity of our procedure argues for its future use, both for theoretical and practical purposes.

To improve the characterization of motor impairment, we compared the sensitivities of a phase plane metric with temporal domain measures derived from integrated squared jerk (ISJ). Five subjects with stroke and a cohort of 21 neurologically intact volunteers performed self-paced, isolated elbow flexions. Analysis of angular trajectories from the stroke group revealed that temporal domain metrics failed to detect a performance deficit at the p < .05 level, while the phase plane metric did resolve a deficit (p < .01). When applied to a subset of movements with arrest periods, the phase measure also uniquely identified impairment (Wilcoxon rank-sum test, p < .001). Finally, when tested on a data-driven model, the phase measure, but not temporal metrics, increased monotonically with the severity of trajectory distortions. We conclude that motion smoothness can be accurately measured in the phase plane.

Reaching tasks are considered well-executed if they appear "smooth," a quality that is typically quantified by its opposite, jerk, the rate of change of acceleration. While jerk is a theoretically sound measure, its application to spastic individuals sometimes yields counter-intuitive results, and does not reveal motor impairment across the workspace. To more generally quantify spontaneous accelerative transients (SATs) within a movement, a pseudo-wavelet transform was devised that iteratively compared angular trajectories to a series of straight-line approximants. Cumulative linear fit errors were expressed in terms of flexion angle, yielding an SAT map of the entire motion. To compare SAT maps with traditional smoothness measures, two scalar indices were extracted from them: residual excursion deviation (RED), representing the integral over Deltatheta and the ratio of peak error to mean error (PEME) on the map. Fifteen subjects, including five subjects with chronic stroke performed elbow flexions throughout their entire ranges of motion, Deltatheta, at a comfortable pace with their arms supported in the transverse plane. Maps revealed that stroke subjects were significantly less coordinated than controls, as measured both by RED: 8.0+/-2.9 x 10(-3) versus 3.1+/-0.8 x 10(-3) and PEME: 6.6+/-0.9 versus 12.1+/-1.9, both P

Inter-limb learning transfer (ILT) between the upper-limbs has been well documented, but no corresponding study of the lower limbs has been done. We investigated ILT in the lower limbs of subjects who learned to move a cursor toward targets within 800 ms using ankle movements: plantar/dorsi-flexion and inversion/eversion. Twenty-two healthy right-dominant subjects were divided into two groups: half performed the tasks first using the right foot (group RL), and the other half performed it first with the left foot (group LR). Targets appeared on a computer screen at head-height while subjects were seated with one foot on a goniometric ankle platform. Subjects were required to move the cursor toward one of three randomly appearing targets under two conditions: (1) neutral or no visual motor rotation, and (2) with a 30 degrees visuo-motor rotation. Performance was quantified by computing the z-score for direction and position errors for each subject and ILT was assessed by comparing group performances for each foot. Results demonstrated that group LR but not group RL experienced significant ILT of directional as well as positional information in both tasks in a manner reflective of the distinctly different functional roles played by the upper and lower limbs.

Because of the high mortality rate after rupture of small abdominal aortic aneurysms (AAAs), surveillance is recommended to detect aneurysm expansion; however, the effects of clinical risk factors on long-term patterns of AAA expansion are poorly characterized.To identify significant clinical risk factors associated with the AAA expansion rate for both constant and accelerated expansion trajectories.A multivariate mixed-effects model was established to identify clinical risk factors associated with the AAA expansion rate. Separate shape factor analysis was used to characterize steady vs accelerated expansion over time. Five hundred sixty-seven patients hospitalized at Veterans Affairs medical centers were randomized to the surveillance arm of the Aneurysm Detection and Management (ADAM) study conducted by the Veterans Affairs Cooperative Studies Program from 1992 to 2000. The patients had an AAA with a maximum diameter from 3.0 to 5.4 cm, which was monitored until a 5.5-cm maximum diameter was reached or the aneurysm became symptomatic. Thirty-three participants were not included in this analysis owing to missing or extraneous values in key predictor variables. The mean (SD) follow-up time was 3.7 (2.0) years.The primary outcome measure was the AAA expansion rate, determined by measurement of the maximum diameter by ultrasonography at regular intervals. The objective to assess the association of clinical variables with the expansion of the AAA was formulated after data collection.The mean (SD) linear expansion rate of AAAs was 0.26 (0.01) cm/y. Current smoking was associated with a 0.05 (0.01)-cm/y increase in the linear expansion rate (95% CI, 0.25-0.28; P .001), diastolic blood pressure with a 0.02 (0.01)-cm/y increase per 10 mm Hg (95% CI, 0.01-0.04; P = .001), and diabetes mellitus with a 0.11 (0.02)-cm/y decrease (95% CI, 0.07-0.16; P .001). Diastolic blood pressure and baseline AAA diameter were associated with accelerated AAA expansion (P = .001 and P .001, respectively).Smoking cessation and control of diastolic blood pressure are direct actions that should be taken to reduce the rate of AAA expansion. Other clinical risk factors, except for diabetes, were not associated with the AAA expansion rate. This study also provides evidence of differing trajectories in AAA expansion over time, a finding that merits further investigation.

The common responses to pressure sensor saturation are extreme: either discarding of data, or wholesale alteration of experimental protocol. Here, we test four simplistic strategies for restoring missing data due to sensor saturation, avoiding such drastic measures.We tested these algorithms on 62 pressure maps collected from 42 individuals (20 M/22 F, 54.1 ± 26.2 years, 1.7 ± 0.1 m, 71.9 ± 17.8 kg) under a variety of seating conditions. These strategies were tested via a cross-validation design, censoring the maximum pressure value in the datasets and measuring prediction error.The four strategies showed various prediction error rates: ? = 0.43 ± 0.14 (simple substitution), ? = 0.16 ± 0.21 (scaled substitution), ? = 0.19 ± 0.21 (feature extraction), and ? = 0.24 ± 0.32 (extrapolation by non-linear modeling).For single-sensor saturation, it may be possible to restore missing data using simple techniques. Implications for Rehabilitation We present a method for imputing missing data from pressure sensor arrays. The implications for rehabilitation are as follows. Improved flexibility in design of protocols concerning interfacial pressure measurement. Restoration of missing data from existing datasets. Reduction in recruitment burden for future studies. Reduction in exposure risk to study participants.

Repetitive reaching movements to a fixed target can be generally characterized by bell-shaped velocity profiles and sigmoidal trajectories with variable morphologies across multiple repetitions. A neuromuscular correspondence of these kinematic variations has thus far eluded electromyographic (EMG) analysis. We recorded EMG and elbow kinematics from fourteen healthy individuals performing repetitive, self-paced, isolated elbow flexions, with their arms supported against gravity. The global kinematic pattern of each flexion was classified as either sigmoidal (S) or non-sigmoidal (NS), based on goodness of fit with analytical curves. Ten of the fourteen subjects generated an approximately equal number of S and NS types (383 movement cycles). Trajectories of the other four subjects were not classifiable or did not vary sufficiently and were excluded from subsequent analysis. A post hoc predictor of trajectory type was derived by testing linear support vector machines trained with a strategically selected 3-feature sub-space of the early phase of enveloped biceps EMG during a leave-one-out cross-validation paradigm. Results showed that EMG features predicted kinematic morphology with sensitivity and specificity both exceeding 80%. The high predictive accuracy suggests neuromotor signals coding for subtle variations in elbow kinematics during self-paced, unloaded motions, can be deciphered from the biceps EMG.

While surface electromyography (SEMG) can accurately register electrical activity of muscles during gait, there are no methods to estimate muscular force non-invasively. To better understand the mechanical behavior of muscle, we evaluated surface muscle pressure (SMP) in conjunction with SEMG. Changes in anterior thigh radial pressure during isometric contractions and gait were registered by pressure sensors on the limb. During isometric knee extensions by a single subject, SMP waveforms correlated well with SEMG (r=0.97), and SEMG onsets preceded those of SMP by 35-40 ms. SMP and SEMG signals were simultaneously recorded from the quadriceps of 10 healthy subjects during gait at speeds of 0.4, 0.8, 1.1, 1.4 and 2.2m/s. Muscle activity onset and cessation times were objectively determined for both modalities, and results showed high intra-class correlations. SMP waveforms were highly consistent from stride to stride, while SEMG waveforms varied widely. SEMG waveforms were typically brief, while SMP waveforms tended to be biphasic and outlasted the SEMG by approximately 40% of gait cycle at all speeds. These results are consistent with mechanical models of muscle, and demonstrate the use of SMP to estimate the timing of knee extensor muscle stiffness during gait.

Ductal carcinoma in situ (DCIS) of the breast is a non-invasive tumor in which cells proliferate abnormally, but remain confined within a duct. Although four distinguishable DCIS morphologies are recognized, the mechanisms that generate these different morphological classes remain unclear, and consequently the prognostic strength of DCIS classification is not strong. To improve the understanding of the relation between morphology and time course, we have developed a 2D in silico particle model of the growth of DCIS within a single breast duct. This model considers mechanical effects such as cellular adhesion and intra-ductal pressure, and biological features including proliferation, apoptosis, necrosis, and cell polarity. Using this model, we find that different regions of parameter space generate distinct morphological subtypes of DCIS, so elucidating the relation between morphology and time course. Furthermore, we find that tumors with similar architectures may in fact be produced through different mechanisms, and we propose future work to further disentangle the mechanisms involved in DCIS progression.