NSF DARE-transforming modeling in neurorehabilitation: perspectives and opportunities from US funding agencies.

In recognition of the importance and timeliness of computational models for accelerating progress in neurorehabilitation, the U.S. National Science Foundation (NSF) and the National Institutes of Health (NIH) sponsored a conference in March 2023 at the University of Southern California that drew global participation from engineers, scientists, clinicians, and trainees. This commentary highlights promising applications of computational models to understand neurorehabilitation ("Using computational models to understand complex mechanisms in neurorehabilitation" section), improve rehabilitation care in the context of digital twin frameworks ("Using computational models to improve delivery and implementation of rehabilitation care" section), and empower future interdisciplinary workforces to deliver higher-quality clinical care using computational models ("Using computational models in neurorehabilitation requires an interdisciplinary workforce" section). The authors describe near-term gaps and opportunities, all of which encourage interdisciplinary team science. Four major opportunities were identified including (1) deciphering the relationship between engineering figures of merit-a term commonly used by engineers to objectively quantify the performance of a device, system, method, or material relative to existing state of the art-and clinical outcome measures, (2) validating computational models from engineering and patient perspectives, (3) creating and curating datasets that are made publicly accessible, and (4) developing new transdisciplinary frameworks, theories, and models that incorporate the complexities of the nervous and musculoskeletal systems. This commentary summarizes U.S. funding opportunities by two Federal agencies that support computational research in neurorehabilitation. The NSF has funding programs that support high-risk/high-reward research proposals on computational methods in neurorehabilitation informed by theory- and data-driven approaches. The NIH supports the development of new interventions and therapies for a wide range of nervous system injuries and impairments informed by the field of computational modeling. The conference materials can be found at https://dare2023.usc.edu/ .

Latino grandparent opportunity to influence family health behaviors: The Healthy Us Grandparent Study (HUGS).

INTRODUCTION: Latino children are the fastest growing population of obese children in the United States, the most obese group of children by race and a significant disparity in childhood obesity. Extended family, often grandparents, are traditionally involved in childcare in Latino family structure, yet their influence on family health behaviors is unclear. This study explored grandparent involvement in the care of Latino children in South Texas and their possible influence on child body mass index (BMI) and family health behaviors to determine if they present an opportunity to improve child obesity treatment plans. METHODS: Partnering with the local school district, we surveyed parents (N = 174) and grandparents (N = 108) of 188 Latino, primary school-age children regarding grandparent care and family health behaviors. We weighed, measured, and interviewed children regarding grandparent care and their own health behaviors. RESULTS: All groups exceeded state and national obesity rates, with almost half the children in overweight or obese categories. Grandparents were routinely present in 30%-67% of the children sampled, dependent on respondent group. We found no significant relationship between grandparent involvement and child BMI, however grandparent cohabitation with the family was associated with less fast-food consumption by children (p = .001) and parents (p = .006) and healthier diet scores for children (p = .008) and grandparents (p = .004). More frequent exercise by parents (r = .33, p = .001) and grandparents (r = .25, p = .012) was associated with more frequent exercise by children. DISCUSSION: This study enhances understanding of grandparent involvement in the care of Latino children and illuminates opportunities to involve grandparents in family-focused, community-supported interventions, incorporating cultural understanding in decreasing Latino childhood obesity. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

How Are Wearable Activity Trackers Adopted in Older Adults? Comparison between Subjective Adoption Attitudes and Physical Activity Performance.

Wearable activity trackers can motivate older adults to engage in the recommended daily amount of physical activity (PA). However, individuals may not maintain their use of the trackers over a longer period. To investigate the attitudes of activity tracker adoption and their effects on actual PA performance, we conducted a three-month study. We gave activity trackers to 16 older adults and assessed attitudes on activity tracker adoption through a survey during the study period. We extracted participants' PA measures, step counts, and moderate and vigorous physical activity (MVPA) times. We observed significant differences in adoption attitudes during the three different periods (χ2(2, 48) = 6.27, p < 0.05), and PA measures followed similar decreasing patterns (F(83, 1357) = 12.56, 13.94, p < 0.00001). However, the Pearson correlation analysis (r = 0.268, p = 0.284) and a Bland-Altman plot indicated a bias between two PA measures. Positive attitudes at the initial stage did not persist through the study period, and both step counts and length of MVPA time showed waning patterns in the study period. The longitudinal results from both measures demonstrated the patterns of old adults' long-term use and adoption. Considering the accuracy of the activity tracker and older adults' athletic ability, MVPA times are more likely to be a reliable measure of older adults' long-term use and successful adoption of activity trackers than step counts. The results support the development of better activity tracker design guidelines that would facilitate long-term adoption among older adults.

Obesity, but not overweight, is associated with plantar light touch sensation in children aged 8 to 16 years: A cross-sectional study.

OBJECTIVE: Increased foot-ground contact loading engenders adaptive glabrous skin thickening and can decrease mechanoreceptor acuity and alter plantar cutaneous sensation. There has not been any research on whether overweight and obesity are similarly associated with normal plantar cutaneous sensation scores in children. This study investigated the associations between normal plantar cutaneous sensation scores and weight status (i.e., healthy weight, overweight, and obesity) in a sample of youth. METHODS: Plantar sensation was tested among 122 participants aged 8 to 16 years (10.3 ± 1.8 years; 140.0 ± 11.2 cm; 44.2 ± 16.0 kg) across the forefoot, midfoot, and rearfoot using Semmes-Weinstein pressure aesthesiometry (0.07 g and 0.4 g monofilaments). Weight status was determined using the Centers for Disease Control and Prevention growth charts. Age- and sex-adjusted models were used to explore the relationships between normal plantar sensation scores and weight status. Significant two-tailed tests were set at p < .05. RESULTS: Only obesity was inversely associated with normal plantar sensation scores on the left (ß = -.241; p = .009) and right (ß = -.222; p = .018) forefeet, left (ß = -.322; p = .001) and right (ß = -.253; p = .007) midfeet, and left (ß = -.286; p = .002) and right (ß = -.228; p = .014) wholefeet (relative to healthy weight) when using the 0.07 g monofilament. There was no association between obesity and plantar sensation when using the 0.4 g monofilament. CONCLUSIONS: Obesity is associated with diminished light touch plantar sensation. Considering previously reported higher mechanical loading and the fact that Merkel cells and the Aßfibers that innervate them are superficial to the hypodermis, adaptive glabrous skin thickening (rather than fat pad thickness) may underlie this association. Contrary to previous suggestions, overweight is not associated with decreased plantar cutaneous sensation.

Association between 90o push-up and cardiorespiratory fitness: cross-sectional evidence of push-up as a tractable tool for physical fitness surveillance in youth.

BACKGROUND: Despite being associated with health outcomes like abdominal adiposity, depression, anxiety, and cardiovascular disease risk among youth, largely, clinicians still do not adopt physical fitness testing. A clarion call for increased surveillance was previously issued, in order to address the US population-level lack of knowledge regarding pervasive inactivity among children. Because schools often do not send home annual physical fitness testing results, many lay parents are unaware of their child's physical fitness or the risk of associated adverse health outcomes. This study investigated associations between musculoskeletal fitness measures (including 90o push-up), cardiorespiratory fitness, and weight status. METHODS: Two hundred and ten students (9.7 ± 1.08 years, 138.6 ± 9.4 cm; 42.3 ± 14.4 kg) across third through fifth grades were tested for cardiorespiratory (i.e., Progressive Aerobic Cardiovascular Endurance Run (PACER)) and musculoskeletal (90o push-up, trunk lift, sit-and-reach and curl-up) fitness. The relationships between measures of musculoskeletal and cardiorespiratory fitness were modeled using a series of linear regression analyses. Models were adjusted for age, sex, and weight status. Significant two-tailed tests were set at p < .05. RESULTS: Of the four musculoskeletal fitness measures, only 90o push-up was significantly associated (ß = .353; p < .001) with PACER test scores (i.e., cardiorespiratory fitness). The related model (R2 = .324; F (4,205) = 26.061; p < .001) accounted for 32% of the variance in cardiorespiratory fitness. 90o push-up was associated with sit-and reach (ß = .298; p < .001) and curl up (ß = .413; p < = .001) test scores. When individually modeled, 90o push-up (ß = -.461; p < .001) and PACER (ß = -.436; p < .001) were inversely associated with weight status. CONCLUSIONS: The 90o push-up test (a measure of upper body muscle strength and endurance) was associated with cardiorespiratory fitness, anterior trunk muscle strength and endurance, and lower back and posterior thigh muscle flexibility in youth aged 8-12 years old. Although the current findings do not establish a causal relationship, it is concluded that the 90o push-up test is a tractable tool for physical fitness surveillance by clinicians, parents, and possibly youth themselves.

Variability of spatiotemporal gait parameters in children with and without Down syndrome during treadmill walking.

BACKGROUND: Increasing walking speed and including bilateral external ankle load have been shown to improve aspects of the gait pattern of children with Down syndrome (DS). However, it is unknown if speed and ankle load improves the cycle-to-cycle variability in a similar way. RESEARCH QUESTION: How do changes of walking speed and external ankle load impact spatiotemporal variability during treadmill walking in children with and without DS? METHODS: Thirteen children with DS (aged 7-10 years) and thirteen age- and sex-matched typically developing (TD) children participated in this study. Subjects completed two bouts of 60-second treadmill walking at two different speeds (slow and fast) and two load conditions (no load and ankle load equaling to 2% bodyweight at each side). Kinematic data was captured using a Vicon motion capture system. Mean and coefficient of variance of spatiotemporal gait variables were calculated and compared between children with and without DS. RESULTS AND SIGNIFICANCE: Across all conditions, the DS group took shorter and wider steps than the TD group, but walked with a similar swing percentage, double support percentage, and foot rotation angle. Further, the DS group demonstrated greater variability of all spatiotemporal parameters, except for step width and foot rotation angle. Our results indicated that children with DS can modulate their spatiotemporal gait pattern accordingly like their TD peers when walking faster on a treadmill and/or with an external ankle load. Smaller step width variability in the DS group suggests that mediolateral stability may be prioritized during treadmill walking to safely navigate the treadmill and complete walking tasks. Similar temporal parameters but distinct spatial parameters in the DS group suggest that they may have developed similar rhythmic control but are confined by their spatial movement limitations.

Musculoskeletal Fitness Measures Are Not Created Equal: An Assessment of School Children in Corpus Christi, Texas.

This study investigated current obesity prevalence and associations between musculoskeletal fitness test scores and the odds of being underweight, overweight, or obese compared to having a healthy weight in elementary school children in Corpus Christi, Texas. The sample analyzed consisted of 492 public elementary school children between kindergarten and fifth grade. Their ages ranged from 5 to 11 years. Trunk lift, 90° push-up, curl-up, and back saver sit and reach tests were administered. Weight status was determined using BMI scores and the CDC growth charts. Obesity prevalence remains high among elementary school-aged children in Corpus Christi, Texas. Higher 90° push-up test scores were most consistently associated with decreased odds of being obese as compared to being overweight and having healthy weight except in kindergarten. Conversely, higher trunk lift test scores were associated with increased odds of being obese in second and fourth grades. When children achieved the minimum score to be classified in the Healthy Fitness Zone, those with healthy weight had similarly low musculoskeletal fitness (i.e., abdominal strength and endurance, hamstring flexibility, and trunk extensor strength and flexibility) as peers with overweight and obesity, especially in the lower grades. It was concluded that increased obesity prevalence in higher grades may be precipitated (at least in part) by low musculoskeletal fitness in the lower grades, especially kindergarten. Given previous associations in the literature, low musculoskeletal fitness may be symptomatic of poor motor skill competence in the current sample. These findings suggest a need for early and focused school-based interventions that leverage both known and novel strategies to combat pediatric obesity in Corpus Christi.

Toe spatiotemporal differences between transition steps when ascending shorter flight stairways of different heights.

BACKGROUND: Studies have typically treated the first and second floor-to-stair transition steps (TS1 and TS2) as one stride. However, because the foot is devoid of plantar cutaneous input from the stair surface at TS1, these steps may have different toe spatiotemporal profiles, and resultantly, different susceptibilities to a trip and/or a fall. This study compared vertical toe clearance, forward velocity, and their respective variability magnitudes between TS1 and TS2 when ascending stairs of different heights. METHODS: Twenty young adults (seven males and 13 females) (21.68 ± 2.49 years; 169.70 ± 9.56 cm; 63.91 ± 9.62 kg) negotiated an intervening three-step staircase placed midpoint on a 10 m walkway. There were three stair heights: low stairs (LS), medium stairs (MS), and high stairs (HS). Vertical toe clearance, forward velocity, and their variability magnitudes were calculated. RESULTS: Vertical toe clearance was only higher (P < 0.05) at TS1 than TS2 in the medium and high stairs. Vertical toe clearance was more variable (P < 0.05) in the low compared to medium stairs. Also, forward toe velocity was greater at TS1 than TS2, but was lower in the medium and high stairs. CONCLUSION: The locomotor system appeared cautious by exaggerating vertical toe clearance at both TS1 and TS2 only in low stairs, possibly due to higher forward toe velocity. If the exaggeration strategy consistently persists, this finding may suggest decreased trip or fall risk at both TS1 and TS2 only when transitioning onto low stairs.

The Effects of Walking Surface on the Gait Pattern of Children With Idiopathic Toe Walking.

Idiopathic toe walking treatments are not conclusively effective. This study investigated the effects of walking surface on gait parameters in children with idiopathic toe walking. Fifteen children with idiopathic toe walking and 15 typically developing children aged 4 to 10 years completed the study, which included a barefoot gait exam over three 4-m walkways. Each of the walkways was covered with a different surface: vinyl tile, carpet, and pea gravel. Temporal-spatial parameters were recorded along with a measure of early heel rise (HR32). Children with idiopathic toe walking and typically developing children shared similarly changed gait patterns on each surfaces. Only HR32 was significantly different between the groups (P < .001). Children with idiopathic toe walking showed significantly less toe-walking on the gravel walkway (P < .001). Walking surface plays a significant role in altering gait patterns in both children with idiopathic toe walking and typically developing children. Walking on a gravel surface should be further explored for idiopathic toe walking.

Children Display Adult-Like Kinetic Patterns in the Time Domain, But Not in the Frequency Domain, While Walking With Ankle Load.

This study used both time and frequency domain analyses to investigate walking patterns with ankle load in children and adults. Twenty-two children aged 7-10 years and 20 young adults participated in this study. Three levels of ankle load were manipulated: no load, low load (2% of body mass on each side), and high load (4% of body mass on each side). An instrumented treadmill was used to register vertical ground reaction force (GRF) and spatiotemporal parameters, and peak vertical GRFs were determined. A frequency domain analysis was conducted on the vertical GRF data. Results demonstrate that, in the time domain, children showed adult-like spatiotemporal parameters and adult-like timing and magnitude of the 2 peak vertical GRFs under each load. In the frequency domain, children produced a lower power from the second harmonic than young adults, although both groups showed the highest power from this harmonic and increased this power with ankle load. It was concluded that children aged 7-10 years may start showing adult-like neuromuscular adaptations to increasing ankle load and display similar spatiotemporal control of foot falls and foot-floor kinetic interaction; however, a frequency domain analysis is effective in revealing different kinetic and neuromuscular characteristics between children and adults.

Walking dynamics in preadolescents with and without Down syndrome.

BACKGROUND: A force-driven harmonic oscillator (FDHO) model reveals the elastic property of general muscular activity during walking. OBJECTIVE: This study aimed to investigate whether children with Down syndrome (DS) have a lower K/G ratio, a primary variable derived from the FDHO model, compared with children with typical development during overground and treadmill walking and whether children with DS can adapt the K/G ratio to walking speeds, external ankle load, and a treadmill setting. DESIGN: A cross-sectional study design was used that included 26 children with and without DS, aged 7 to 10 years, for overground walking and 20 of them for treadmill walking in a laboratory setting. METHODS: During overground walking, participants walked at 2 speeds: normal and fastest speed. During treadmill walking, participants walked at 75% and 100% of their preferred overground speed. Two load conditions were manipulated for both overground and treadmill walking: no load and an ankle load that was equal to 2% of body mass on each side. RESULTS: Children with DS showed a K/G ratio similar to that of their healthy peers and increased this ratio with walking speed regardless of ankle load during overground walking. Children with DS produced a lower K/G ratio at the fast speed of treadmill walking without ankle load, but ankle load helped them produce a K/G ratio similar to that of their healthy peers. LIMITATIONS: The FDHO model cannot specify what muscles are used or how muscles are coordinated for a given motor task. CONCLUSIONS: Children with DS show elastic property of general muscular activity similar to their healthy peers during overground walking. External ankle load helps children with DS increase general muscular activity and match their healthy peers while walking fast on a treadmill.

Frequency domain analysis of ground reaction force in preadolescents with and without Down syndrome.

Children with Down syndrome (DS) display less stable and coordinated gait patterns in the time domain than their healthy peers. However, little is known about whether this group difference exists in the frequency domain. The purpose of this study was to investigate differences in vertical ground reaction force (GRF) in the frequency domain between preadolescents with and without DS. Twenty children at 7-10 years of age with and without DS participated in this study. Participants walked on an instrumented treadmill at two speeds with and without external ankle load. Vertical GRF was collected and the data was processed through a Fourier transform. Frequency content variables included fundamental frequency, power of the first five harmonics, and the frequency and number of harmonics at 95%, 99% and 99.5% of total power. Preadolescents with DS had a similar fundamental frequency as their healthy peers even though the DS group walked at slower speeds. The DS group displayed a different power spectrum of the first five harmonics and had the lower frequency and number of harmonics at 99% and 99.5% of total power. However, walking at a faster speed with external ankle load helped the DS group produce a power spectrum more similar to healthy children. Frequency content of vertical GRF provides additional assessment parameters in functional gait evaluation of children with DS. Treadmill intervention at a faster speed and with external ankle load appears to be clinically promising and needs further investigation.

Kinetic patterns of treadmill walking in preadolescents with and without Down syndrome.

This study investigated the effect of both walking speed and external ankle load on the kinetic patterns of treadmill walking in preadolescents with and without Down syndrome (DS). Ten preadolescents with DS and ten age- and gender-matched children with typical development (TD) participated in this study. We manipulated two treadmill speeds and two external ankle loads. Treadmill speeds were equal to 75% and 100% of the preferred overground walking speed. Two load conditions were with and without external ankle load which was equal to 2% of body weight on each side. We used an instrumented treadmill to collect vertical ground reaction force (GRF). Both timing and magnitude of peak GRFs, the loading and unloading rates, and various impulses were calculated from the GRF data. The results show that the DS group produced a shorter duration of propulsion, a lower FZ2 (second peak GRF) and vertical propulsive impulse, a higher loading rate and a lower unloading rate than the TD group. At a faster treadmill speed the DS group increased the duration of propulsion, the unloading rate and the vertical propulsive impulse, but reduced the magnitude of FZ2. External ankle load helped the DS group increase FZ2 and vertical propulsive impulse and might facilitate the push off and the initiation of leg swing during treadmill walking. External ankle load may therefore be included in the future physical intervention and exercise programs for the DS group to strengthen leg muscles and develop more efficient push off during locomotion.