Changes in lower limb co-contraction and stiffness by toddlers with Down syndrome and toddlers with typical development during the acquisition of independent gait

During gait acquisition, children learn to use their changing resources to meet the requirements of the task. Compared to typically developing toddlers (TD), toddlers with Down syndrome (DS) have functionally different musculoskeletal characteristics, such as hypotonia, and joint and ligament laxity, that could produce a reduced passive stiffness. The interplay between this inherently lower passive stiffness and the demands of walking may result in different strategies during gait acquisition. This study compared normalized global stiffness and lower limb's co-contraction indices (CCI) used by toddlers with TD (n=12) and with DS (n=12), during the early stages of gait acquisition. Stiffness and CCI were normalized by gravitational torque (mLg) in both phases of gait (stance, swing). Five longitudinal evaluations were conducted from the onset of locomotion until three months post-acquisition. All children were video taped and had electromyographic (EMG) recordings from muscle pairs of one leg, which were used to calculate CCI of hip, knee, ankle, and total leg CCI. Body and lower limb stiffness were calculated according to a hybrid pendulum resonance equation. Results from ANOVAs revealed no group differences on stiffness or on CCI's during stance but children with DS showed greater CCI during swing. Despite the structural musculoskeletal differences between toddlers with TD and with DS, the similarities observed in their processes of gait development suggest functional equivalences.     

Parents of children with Down Syndrome: Do resilience and social support matter to their experience of carer stress?

The study investigated personal resilience influences on the relationship between social support and parenting-stress among parents of children with Down syndrome (DS) in a Nigerian sample. One hundred and ninety three parent-carers of children with DS participated in the study (mothers?=?59%; mean age?=?46.47, age range?=?21 to 67, SD?=?10.42). The parent-carers responded to the measures of parenting-stress, perceived social support, and resilience. The result of the moderated multiple linear regression showed that parents with high social support and resilience have lower level of parenting-stress. Higher personal resilience significantly moderated the relationship between social support and parenting-stress so that parent-carers with low level of social support and higher personal resilience had lower level of parenting-stress. Resilience and social support oriented therapy appears to have efficacy for helping parent-carers of children with DS to manage their stress arising from raising such children.     

Body esteem and body fat in British school children from different ethnic groups

The aim of the study was to examine the relationship between body esteem and body fat in British school children. Two hundred and seventy seven, 11–14-year-old children from central England took part in the study. Body esteem was measured using the Body Esteem Scale for children and percent body fat was determined by skin-fold measures. Results indicate that body esteem and adiposity were negatively related for the whole sample, for boys and girls and for White children, Black children and Asian children. Factorial ANOVA also indicated differences in body esteem according to gender and ethnicity. Boys and Black children had significantly higher body esteem than girls and Asian children respectively. Differences in body fat were also evident according to gender with boys being leaner than girls. No differences in body esteem or body fat were evident across school years.     

Maternal sensitivity and overt aggression in young children with Down syndrome

Children with genetic syndromes offer a unique opportunity to combine genetic and environmental approaches to the study of aggression. Children with genetic syndromes associated with developmental delay are at increased risk for behavior problems, but little is known about risk and resilience factors. In this study, we examined maternal sensitivity of mothers of children with Down syndrome using home observations when their children were 2, 3, and 5 years old, and relations with maternal reports and observations of overt aggression at school at age 5. Maternal sensitivity at ages 2 and 3 years did not significantly predict child aggression at age 5, but low maternal sensitivity at age 5 was significantly related to overt aggression at both home and school. By replicating and extending earlier work, this study informs developmental theory and identifies an important maternal variable related to aggression in children with Down syndrome.     

Developmental patterns in body esteem from late childhood to young adulthood: A growth curve analysis

This study examines the long-term development of different domains of body esteem (BE), the most salient domain of adolescents' global self-esteem. The 11-year longitudinal study of Swedish youths, covering ages 10–21, showed that BE undergoes significant change from late childhood to young adulthood, with growth curve models revealing different developmental paths between domains and across gender. For girls, general appearance esteem and weight esteem decreased in the early adolescent phase and then stabilized. For boys, similar patterns were evident, but weight esteem was subject to change also in late adolescence. The third BE domain, appearance-evaluations ascribed to others, displayed a distinct developmental trajectory. This was the only domain where no gender differences were noted in terms of mean levels. It was also the only domain that demonstrated positive increases over time. Findings from the present long-term study contribute to a more coherent picture of the development of BE from late childhood and into young adulthood.     

The impact of weight, sex, and race/ethnicity on body dissatisfaction among urban children

The purpose of the current study was to examine the relative contributions of weight status, race/ethnicity, sex, and age on body dissatisfaction in a large group of diverse children. Participants were 4th–6th graders (N = 1212) in ten inner-city schools who participated in an obesity prevention study previously published. Children completed the body dissatisfaction subscale of the Eating Disorder Inventory-2 (EDI-2), and weight status was assessed by measured weights and heights. Multiple regression analyses were conducted. Relative weight status was the strongest predictor of body dissatisfaction, followed by race/ethnicity, and sex. Body dissatisfaction was greatest in obese, Asian, and female children. Overall, results indicated that children's body dissatisfaction varies based on relative weight status, as well as race/ethnicity and sex among urban children. Results highlight the strong need for additional research so that more definitive conclusions may be drawn regarding the development of body image among diverse groups of children.     

Locomotor body scheme

The concept of body schema has been introduced and widely discussed in the literature to explain various clinical observations and distortions in the body and space representation. Here we address the role of body schema related information in multi-joint limb motion. The processing of proprioceptive information may differ significantly in static and dynamic conditions since in the latter case the control system may employ specific dynamic rules and constraints. Accordingly, the perception of movement, e.g., estimation of step length and walking distance, may rely on a priori knowledge about intrinsic dynamics of limb segment motion and inherent relationships between gait parameters and body proportions. The findings are discussed in the general framework of space and body movement representation and suggest the existence of a dynamic locomotor body schema used for controlling step length and path estimation.     

Effects on fathers of children with down syndrome

This study investigated research evidence for eight assertions found in the literature about effects on fathers of children with disabilities. Eighty-seven fathers of children with Down syndrome completed questionnaire instruments designed to measure demographic variables, adaptation, stress, personality, social support and marital functioning. The results provided little support for most of the assertions. It is concluded that the existing literature provides a somewhat erroneous perspective of the experiences of such fathers. These findings reinforce the need for further research specifically with fathers of children with mental retardation.     

Expression des états mentaux chez les enfants atteints du Syndrome de Williams : analyse d'interactions collaboratives mère-enfant

People affected by Williams syndrome (WS), a rare genetic disease, are characterized by a personality noted for its “hypersociability” along with relatively spared language in the face of significant cognitive deficit. Our research focuses on the intersection of two domains by examining linguistic markers of this sociability: how do children with WS perform in a collaborative interaction? Do they express mental states, how and what kind? And do they answer to the mental states expressed by others? We present data from three matched groups of 12 each: children with WS, children with Down syndrome (DS) and control group (CO) in a task in which the mother and child interacted in a standardized collaborative situation with a social stake (a precise aim to reach). The children with WS had comparable difficulties to those with DS in the interaction: they produced fewer turns and fewer utterances than controls. Children with WS produced more expressive mental states than either the DS or CO group. The WS children had more difficulties cooperating than did either the DS or CO children: the unrealized requests by the children are more numerous in the WS group. Thus in a collaborative interaction, the children with WS present a unique profile: difficulty in maintaining and participating in the interaction contrasting with a facility in expressing mental states about feelings and emotions.     

Support vector machine for classification of walking conditions of persons after stroke with dropped foot

Walking with dropped foot represents a major gait disorder, which is observed in hemiparetic persons after stroke. This study explores the use of support vector machine (SVMs) to classify different walking conditions for hemiparetic subjects. Seven participants with dropped foot (category 4 of functional ambulatory category) walked in five different conditions: level ground, stair ascent, stair descent, upslope, and downslope. The kinematic data were measured by two portable sensor units, each comprising an accelerometer and gyroscope attached to the lower limb on the shank and foot segments. The overall classification accuracy of stair ascent, stair descent, and other walking conditions was 92.9% using input features from the sensor attached to the shank. It was further improved to 97.5% by adding two more inputs from the sensor attached to the foot. Stair ascent was also classified by the inputs from the foot sensor unit with 96% accuracy. The performance of an SVM was shown to be superior to that of other machine learning methods using artificial neural networks (ANN) and radial basis function neural networks (RBF). The results suggested that the SVM classification method could be applied as a tool for pathological gait analysis, pattern recognition, control signals in functional electrical stimulation (FES) and rehabilitation robot, as well as activity monitoring during rehabilitation of daily activities.     

Self-objectification,body image disturbance,and eating disorder symptoms in young Australian children

Self-objectification has been examined extensively in adult populations. Despite theoretical evidence suggesting that children may also be vulnerable to experiencing self-objectification, whether children do self-objectify has not been determined. Accordingly, the present study examined the degree to which children self-objectify. The prevalence of body image and eating disturbances in this population, and the relationship between self-objectification and these disturbances, were also investigated. Results from over 250 boys and girls aged 6–11 years revealed that young girls report levels of self-objectification that are similar to those observed among older girls and women. Self-objectification was also found to be meaningfully related to body image and eating disturbances in children. A significant proportion of children reported body dissatisfaction and a minority engaged in disordered eating behaviours in the four weeks prior to the assessment. These results suggest that children may be at risk of experiencing the negative psychological outcomes associated with self-objectification.     

Measures of dynamic stability: Detecting differences between walking overground and on a compliant surface

Numerous measures of dynamic stability have been proposed to gauge fall risk in the elderly, including stride interval variability and variability of the center of mass. However, these measures have been deemed inadequate because they do not take into account temporal information. Therefore, research on the measurement of dynamic stability has turned to other analysis methods such as stride interval dynamics and the maximum Lyapunov exponent. Stride interval dynamics reflect the statistical persistence of an individual’s stride interval time series and the Lyapunov exponent quantifies local dynamic stability – the sensitivity of the system to infinitesimal perturbations. In this study, we compare the ability of these measurement tools to detect changes between overground and compliant-surface walking, a condition known to affect stability, to determine their aptness as measures of dynamic stability. Fourteen able-bodied participants completed three 15 min walks, two overground and one on a compliant surface. Our results show that the Lyapunov exponent may be more sensitive to gait changes than stride interval dynamics and gait variability measures.     

Cognitive performance is improved while walking: Differences in cognitive–sensorimotor couplings between children and young adults

We investigated how 9-year-olds and young adults performed a working memory task under different difficulty conditions while walking on a treadmill. Stride-length and stride-time variability tended to decrease with cognitive load in young adults, whereas children showed an increase in walking variability when cognitive load was very high. Participants in both age groups improved their cognitive performance when walking at their preferred speed as opposed to sitting or walking at a fixed, non-preferred speed. We conclude that the interaction of walking and cognitive performance is influenced by sharing resources between two tasks, and that performance improvements in cognition may be caused by an exercise-induced activation of resources.