Interaction between the development of postural control and the executive function of attention

Multitasking across the lifespan in different task contexts

We assessed lifespan development of multitasking in a sample of 187 individuals aged 8-82 years. Participants performed a visuo-spatial working memory (VSWM) task together with either postural control or reaction time (RT) tasks. Using criterion-referenced testing we individually adjusted difficulty levels for the VSWM task to control for single-task differences. Age-differences in single-task performances followed U-shaped patterns with young adults outperforming children and older adults. Multitasking manipulations yielded robust performance decrements in VSWM, postural control and RT tasks. Presumably due to our adjustment of VSWM challenges, costs in this task were small and similar across age groups suggesting that age-differential costs found in earlier studies largely reflected differences already present during single-task performance. Age-differences in multitasking costs for concurrent tasks depended on specific combinations. For VSWM and RT task combinations increases in RT were the smallest for children but pronounced in adults highlighting the role of cognitive control processes. Stabilogram diffusion analysis of postural control demonstrated that long-term control mechanisms were affected by concurrent VSWM demands. This interference was pronounced in older adults supporting concepts of compensation or increased cognitive involvement in sensorimotor processes at older age. Our study demonstrates how a lifespan approach can delineate the explanatory scope of models of human multitasking.

Locomotor-cognitive dual-tasking in children with developmental coordination disorder

Introduction

Children with Developmental Coordination Disorder (DCD) demonstrate deficits in predictive motor control and aspects of cognitive control compared with their typically developing (TD) peers. Adjustment to dynamic environments depends on both aspects of control and the deficits for children with DCD may constrain their ability to perform daily actions that involve dual-tasking. Under the assumption that motor-cognitive integration is compromised in children with DCD, we examined proportional dual-task costs using a novel locomotor-cognitive dual-task paradigm that enlisted augmented reality. We expect proportional dual-task performance costs to be greater for children with DCD compared to their TD peers.

Methods

Participants were 34 children aged 6-12 years (16 TD, 18 DCD) who walked along a straight 12 m path under single- and dual-task conditions, the cognitive task being visual discrimination under simple or complex stimulus conditions presented via augmented reality. Dual-task performance was measured in two ways: first, proportional dual-task costs (pDTC) were computed for cognitive and gait outcomes and, second, within-trial costs (p-WTC) were measured as the difference on gait outcomes between pre- and post-stimulus presentation.

Results

On measures of pDTC, TD children increased their double-limb support time when walking in response to a dual-task, while the children with DCD increased their locomotor velocity. On p-WTC, both groups increased their gait variability (step length and step width) when walking in response to a dual-task, of which the TD group had a larger proportional change than the DCD group. Greater pDTCs on motor rather than cognitive outcomes were consistent across groups and method of dual-task performance measurement.

Discussion

Contrary to predictions, our results failed to support dramatic differences in locomotor-cognitive dual-task performance between children with DCD and TD, with both groups tending to priorities the cognitive over the motor task. Inclusion of a within-trial calculation of dual-task interference revealed an expectancy effect for both groups in relation to an impending visual stimulus. It is recommended that dual-task paradigms in the future continue to use augmented reality to present the cognitive task and consider motor tasks of sufficient complexity to probe the limits of performance in children with DCD.

Effects of the BalanCI on Working Memory and Balance in Children and Young Adults With Cochleovestibular Dysfunction

OBJECTIVES

This study aimed to: (1) determine the interaction between cognitive load and balance in children and young adults with bilateral cochleovestibular dysfunction who use bilateral cochlear implants (CIs) and (2) determine the effect of an auditory balance prosthesis (the BalanCI) on this interaction. Many (20 to 70%) children with sensorineural hearing loss experience some degree of vestibular loss, leading to poorer balance. Poor balance could have effects on cognitive resource allocation which might be alleviated by the BalanCI as it translates head-referenced cues into electrical pulses delivered through the CI. It is hypothesized that children and young adults with cochleovestibular dysfunction will demonstrate greater dual-task costs than typically-developing children during dual balance-cognition tasks, and that BalanCI use will improve performance on these tasks.

DESIGN

Study participants were 15 typically-developing children (control group: mean age ± SD = 13.6 ± 2.75 years, 6 females) and 10 children and young adults who use bilateral CIs and have vestibular dysfunction (CI-V group: mean age ± SD=20.6 ± 5.36 years, 7 females). Participants completed two working memory tasks (backward auditory verbal digit span task and backward visuospatial dot matrix task) during three balance conditions: seated, standing in tandem stance with the BalanCI off, and standing in tandem stance with the BalanCI on. Working memory performance was quantified as total number of correct trials achieved. Postural stability was quantified as translational and rotational path length of motion capture markers worn on the head, upper body, pelvis, and feet, normalized by trial time.

RESULTS

Relative to the control group, children and young adults in the CI-V group exhibited poorer overall working memory across all balance conditions ( p = 0.03), poorer translational postural stability (larger translational path length) during both verbal and visuospatial working memory tasks ( p < 0.001), and poorer rotational stability (larger rotational path length) during the verbal working memory task ( p = 0.026). The CI-V group also exhibited poorer translational ( p = 0.004) and rotational ( p < 0.001) postural stability during the backward verbal digit span task than backward visuospatial dot matrix task; BalanCI use reduced this stability difference between verbal and visuospatial working memory tasks for translational stability overall ( p > 0.9), as well as for rotational stability during the maximum working memory span (highest load) participants achieved in each task ( p = 0.91).

CONCLUSIONS

Balance and working memory were impaired in the CI-V group compared with the control group. The BalanCI offered subtle improvements in stability in the CI-V group during a backward verbal working memory task, without producing a negative effect on working memory outcomes. This study supports the feasibility of the BalanCI as a balance prosthesis for individuals with cochleovestibular impairments.

Biological and environmental factors may affect children's executive function through motor and sensorimotor development: Preterm birth and cerebral palsy

Disruptive biological and environmental factors may undermine the development of children's motor and sensorimotor skills. Since the development of cognitive skills, including executive function, is grounded in early motor and sensorimotor experiences, early delays or impairments in motor and sensorimotor processing often trigger dynamic developmental cascades that lead to suboptimal executive function outcomes. The purpose of this perspective paper is to link early differences in motor/sensorimotor processing to the development of executive function in children born preterm or with cerebral palsy. Uncovering such links in clinical populations would improve our understanding of developmental pathways and key motor and sensorimotor skills that are antecedent and foundational for the development of executive function. This knowledge will allow the refinement of early interventions targeting motor and sensorimotor skills with the goal of proactively improving executive function outcomes in at-risk populations.

Association between the level of attention and dual-task costs on postural sway and cognitive yield in children, adolescents, and young adults

BACKGROUND

Postural stability requires attentional resources. Dual-task paradigms are used to investigate the attentional demand of the studied tasks. However, no studies have been conducted on the subjects' level of attention, analyzing its association with dual-task costs (DTC).

RESEARCH QUESTION

To evaluate the attentional level and DTC on postural sway and cognitive yield in children, adolescents, and young adults, investigating age-related differences, and to analyze if the participants' attention level is associated with DTC.

METHODS

Postural sway and cognitive-yield of 30 children, 24 adolescents, and 32 young adults were assessed in a dual-task paradigm. We calculated DTC on postural sway and cognitive yield. Attention level was tested using Psychological Battery for Attention Assessment. We tested the association between DTC and attention level.

RESULTS

Young adults showed higher DTC on area and velocity of postural sway than children and adolescents. No differences in DTC on cognitive yield were found between the groups. Children showed lower attention levels than adolescents and young adults. Attention level was negatively associated with DTC on cognitive yield in young adults. Focused Attention is responsible for 24.4% of the variance in DTC on cognitive yield.

CONCLUSION

Age impacts DTC on postural stability, but not on cognitive performance. The smaller changes in sway found in children/adolescents when dual-tasking, potentially reflect less developed attentional levels and postural control, which make them performing postural tasks closed to their stability boundaries, and, therefore, make them prioritize stability protection more than adults. Similar DTC on cognition between groups may reflect an equalization of the chosen cognitive task at everyone's difficulty level. The lower attention levels of children may reflect an attentional system in development, with prioritization o postural tasks when dual-tasking to maintain stability. Although attention level increases throughout age, attention only predicted DTC on cognition. Better Focused Attention's levels predicted lower DTC on cognitive yield for young adults.

Working memory is a core executive function supporting dual-task locomotor performance across childhood and adolescence

Most daily-life ambulatory tasks involve dual tasking, for example, talking while walking. In children, the evidence supporting the effects of age on dual tasking is confounded by the difficulty of the cognitive task and lack of adjustment to suit individual cognitive abilities. To address this issue, the current study examined the effects of age, cognitive load, and executive functioning on the degree of dual-task gait interference across childhood and adolescence. We tested 120 typically developing children aged 6-11 years, adolescents aged 12-16 years, and young adults aged 18-25 years. Participants were asked to walk while performing a visuospatial working memory task at two levels of cognitive load (easy and difficult) adjusted to suit each participant's cognitive ability. Spatiotemporal characteristics and intra-individual variability of gait were measured using a GAITRite electronic walkway. Irrespective of the cognitive load level, children aged 6 to 11 years showed greater dual-task gait interference for selective spatiotemporal gait characteristics; however, the younger children showed a trade-off pattern in gait variability whereby they prioritized gait stability at the expense of cognitive performance. Our results also showed that age and working memory capacity were significant predictors of dual-task interference for a range of complementary gait parameters in the combined sample. Importantly, working memory capacity was part of a moderating relationship between age and dual-task gait interference. These findings emphasize the importance of dual-task prioritization strategies in younger children and highlight the role of individual differences in working memory capacity in performance in dual-task gait situations.

Using a dual-task paradigm to investigate motor and cognitive performance in children with intellectual disability

BACKGROUND

The purpose of the current study was to evaluate the effects of dual-task (DT) constraints on walking performance in children with intellectual disability (ID).

METHODS

Fifteen children with intellectual disability and fifteen age-matched typically developed children were asked to walk at a preferred speed: along a path (baseline condition), while carrying a glass of water and while quoting animal names.

RESULTS

The present study findings showed that DTs affect walking performance of both typically developed children and those with intellectual disability. In children with intellectual disability, DT walking decrements were significantly higher when performing a concurrent motor task than cognitive one.

CONCLUSIONS

DT constraints with a secondary motor or cognitive tasks seemed challenging for children with intellectual disability suggesting that future treatments or assessments should consider using DT constraints to manipulate the difficulty of tasks.

Relationship between attention and balance: a dual-task condition study in children

This study explored the relationship between motor functions and attention in children aged 4-5 years. A sample of 85 children was collected from a primary school (44 boys and 41 girls). We applied a standardized continuous attention performance test, the Kiddie Continuous Performance Test, under two conditions (sitting and balancing). Data were collected from two standardized balance tests, the Battelle and Pediatric Balance Scale. There was a significant relationship between attention and balance and gender differences that may condition the way to address balance issues in boys and girls. Gender should be considered when addressing balance problems to get efficient interventions. Balance skill may be a contributing factor in attention-deficit/hyperactivity disorder.

On-Field Signs Predict Future Acute Symptoms After Sport-Related Concussion: A Structural Equation Modeling Study

OBJECTIVES

This study investigated the relationship between on-field, objective signs immediately following sport-related concussion and self-reported symptom endorsement within 1 day post injury.

METHODS

A retrospective case series of 237 concussed high school athletes was performed. On-field signs were evaluated immediately post injury. Self-reported symptoms (2 clusters) were collected within 1 day post injury. A two-step structural equation model and follow-up bivariate regression analyses of significant on-field signs and symptom clusters were performed.

RESULTS

Signs of immediate memory, β=0.20, p=.04, and postural instability, β=0.19, p < .01, significantly predicted a greater likelihood of endorsing the cognitive-migraine-fatigue symptom cluster within 1 day post injury. Regarding signs correlated with specific symptoms, immediate memory was associated with symptoms of trouble remembering, χ 2 =37.92, p < .001, odds ratio (OR)=3.89 (95% confidence interval (CI) [2.47, 6.13]), and concentration difficulties, χ 2 =10.84, p=.001, OR=2.13 (95% CI [1.37, 3.30]). Postural instability was associated with symptom endorsement of trouble remembering, χ 2 =12.08, p < .001, OR=1.76 (95% CI [1.29, 2.40]).

CONCLUSIONS

Certain post-concussion on-field signs exhibited after injury were associated with specific symptom endorsement within 1 day post injury. Based on these associations, individualized education-based interventions and academic accommodations may help reduce unanticipated worry from parents, students, and teachers following a student-athlete's sport-related concussion, especially in cases of delayed onset symptoms. (JINS, 2018, 24, 476-485).

The Effect of Visual Environmental Distraction on Gait Performance in Children

PURPOSE

Identify the effect of visual distraction on gait parameters in children and describe the role of walking experience (WE) in the management of visual distraction.

METHODS

Forty-two typically developing children, mean age 43.2 months (SD = 22.9) participated and were divided into three groups according to WE: early walkers (6-11 months of WE), preschool walkers (12-37 months of WE), and experienced walkers (38-79 months of WE). Gait parameters measured under two conditions (no visual distraction and with visual distraction) included: velocity, step length, step width, and double limb support percentage (DLS%) of gait cycle. Multivariate analysis of variance assessed differences in gait between groups (effect of WE) and within groups (effect of condition).

RESULTS

Significant main effects of WE group F(8,74) = 5.300, p ≤.001 and visual distraction condition F(4,36) = 2.586, p = 0.053 were found. Visual environmental distraction significantly affected gait performance in children regardless of walking experience. Velocity decreased from 110.04 to 97.73 cm/sec (p = 0.003) while DLS% of gait cycle increased from 18.29% to 20.39% (p = 0.025).

CONCLUSIONS

Results suggest physical therapists need to consider attentional requirements when assessing gait; even in children with more WE. If attention to task is a limiting factor for performance or learning of a motor task, it may need to be addressed directly as part of the treatment plan.

Attentional load of walking in children aged 7-12 and in adults

The amount of attentional resources necessary to walk in children, and how they evolve during childhood remains unclear. This study examined children's gait parameters in different dual-task conditions. 53 children, divided into two age groups (7-9 and 10-12 years old), and 18 adults walked on a mat in three different cognitive conditions: watching a video (video condition), listening its soundtrack (audio condition), and without any additional task (control condition). Questions were asked at the end of the video and audio conditions to make sure that participants were paying attention to the stimuli. A GAITRite® system was used for recording the gait data. Results showed an increase of velocity and step duration, and a decrease of cadence and percentage of double limb support duration from 7 years of age to adulthood during dual-task walking compared with single-task walking. This improvement seemed to be linear from 7 years to adults' age. The interference of dual-task on gait was larger for the video than for the auditory task and decreased with age. We concluded that walking requires a significant amount of attentional resources in children and that children rely more than adults on visual processes for walking.

Effects of distractors on upright balance performance in school-aged children with attention deficit hyperactivity disorder, preliminary study

INTRODUCTION

Attention deficit hyperactivity disorder is a common impairing neuropsychiatric disorder with onset in early childhood. Almost half of the children with attention deficit hyperactivity disorder also experience a variety of motor-related dysfunctions ranging from fine/gross motor control problems to difficulties in maintaining balance.

OBJECTIVES

The main purpose of this study was to investigate the effects of distractors two different auditory distractors namely, relaxing music and white noise on upright balance performance in children with attention deficit hyperactivity disorder.

METHODS

We compared upright balance performance and the involvement of different sensory systems in the presence of auditory distractors between school-aged children with attention deficit hyperactivity disorder (n=26) and typically developing controls (n=20). Neurocom SMART Balance Master Dynamic Posturography device was used for the sensory organization test. Sensory organization test was repeated three times for each participant in three different test environments.

RESULTS

The balance scores in the silence environment were lower in the attention deficit hyperactivity disorder group but the differences were not statistically significant. In addition to lower balance scores the visual and vestibular ratios were also lower. Auditory distractors affected the general balance performance positively for both groups. More challenging conditions, using an unstable platform with distorted somatosensory signals were more affected. Relaxing music was more effective in the control group, and white noise was more effective in the attention deficit hyperactivity disorder group and the positive effects of white noise became more apparent in challenging conditions.

CONCLUSION

To the best of our knowledge, this is the first study evaluating balance performance in children with attention deficit hyperactivity disorder under the effects of auditory distractors. Although more studies are needed, our results indicate that auditory distractors may have enhancing effects on upright balance performance in children with attention deficit hyperactivity disorder.

Changes in Standing and Walking Performance Under Dual-Task Conditions Across the Lifespan

Simultaneous performance of a postural and a concurrent task is rather unproblematic as long as the postural task is executed in an automatic way. However, in situations where postural control requires more central processing, cognitive resources may be exceeded by the addition of an attentionally demanding task. This may lead to interference between the two tasks, manifested in a decreased performance in one or both tasks (dual-task costs). Owing to changes in attentional demands of postural tasks as well as processing capacities across the lifespan, it might be assumed that dual-task costs are particularly pronounced in children and older adults probably leading to a U-shaped pattern for dual-task costs as a function of age. However, these changes in the ability of dual-tasking posture from childhood to old age have not yet been systematically reviewed. Therefore, Web of Science and PubMed databases were searched for studies comparing dual-task performance with one task being standing or walking in healthy groups of young adults and either children or older adults. Seventy-nine studies met inclusion criteria. For older adults, the expected increase in dual-task costs could be confirmed. In contrast, in children there was only feeble evidence for a trend towards enlarged dual-task costs. More good-quality studies comparing dual-task ability in children, young, and, ideally, also older adults within the same paradigm are needed to draw unambiguous conclusions about lifespan development of dual-task performance in postural tasks. There is evidence that, in older adults, dual-task performance can be improved by training. For the other age groups, these effects have yet to be investigated.

Moving to Capture Children's Attention: Developing a Methodology for Measuring Visuomotor Attention

Attention underpins many activities integral to a child's development. However, methodological limitations currently make large-scale assessment of children's attentional skill impractical, costly and lacking in ecological validity. Consequently we developed a measure of 'Visual Motor Attention' (VMA)-a construct defined as the ability to sustain and adapt visuomotor behaviour in response to task-relevant visual information. In a series of experiments, we evaluated the capability of our method to measure attentional processes and their contributions in guiding visuomotor behaviour. Experiment 1 established the method's core features (ability to track stimuli moving on a tablet-computer screen with a hand-held stylus) and demonstrated its sensitivity to principled manipulations in adults' attentional load. Experiment 2 standardised a format suitable for use with children and showed construct validity by capturing developmental changes in executive attention processes. Experiment 3 tested the hypothesis that children with and without coordination difficulties would show qualitatively different response patterns, finding an interaction between the cognitive and motor factors underpinning responses. Experiment 4 identified associations between VMA performance and existing standardised attention assessments and thereby confirmed convergent validity. These results establish a novel approach to measuring childhood attention that can produce meaningful functional assessments that capture how attention operates in an ecologically valid context (i.e. attention's specific contribution to visuomanual action).

Effect of Cognitive Load on Seating Posture in Children

Although children are frequently required to sit upright, it is often difficult to maintain this posture when performing cognitive tasks. Information about the relationship between a cognitive tasks and postural seating control is important for children to complete tasks more effectively. To determine the muscle activity and body sway of children in a seated posture while performing a cognitive task, changes in muscle activity and center of pressure (COP) were recorded while 4(th) grade children performed arithmetic tasks. Electromyography was recorded from the internal oblique and lumbar multifidus muscles, and the COP was recorded using a baropodometer placed on the stool. These variables were measured during easy (EA) and difficult (DA) arithmetic tasks. EMG activity decreased during the EA and DA tasks, while the COP was displaced in the DA task. The results of the arithmetic tasks were not related to the EMG or COP changes. Attention to maintain a seated posture may be reduced when children perform cognitive tasks. Therefore, it may be better to allow children to alter their posture especially when they are performing difficult tasks. In this research, we only used arithmetic tasks as the cognitive exercise, and therefore, other types of tasks should be examined.

Classification of body movements based on posturographic data

The human body, standing on two feet, produces a continuous sway pattern. Intended movements, sensory cues, emotional states, and illnesses can all lead to subtle changes in sway appearing as alterations in ground reaction forces and the body's center of pressure (COP). The purpose of this study is to demonstrate that carefully selected COP parameters and classification methods can differentiate among specific body movements while standing, providing new prospects in camera-free motion identification. Force platform data were collected from participants performing 11 choreographed postural and gestural movements. Twenty-three different displacement- and frequency-based features were extracted from COP time series, and supplied to classification-guided feature extraction modules. For identification of movement type, several linear and nonlinear classifiers were explored; including linear discriminants, nearest neighbor classifiers, and support vector machines. The average classification rates on previously unseen test sets ranged from 67% to 100%. Within the context of this experiment, no single method was able to uniformly outperform the others for all movement types, and therefore a set of movement-specific features and classifiers is recommended.

Performance of a cognitive, but not visual, secondary task interacts with alcohol-induced balance impairment in novice and experienced motorcycle riders

The appropriateness of applying drink driving legislation to motorcycle riding has been questioned as there may be fundamental differences in the effects of alcohol on driving and motorcycling. It has been suggested that alcohol may redirect riders' focus from higher-order cognitive skills such as cornering, judgement and hazard perception, to more physical skills such as maintaining balance. To test this hypothesis, the effects of low doses of alcohol on balance ability were investigated in a laboratory setting. The static balance of twenty experienced and twenty novice riders was measured while they performed either no secondary task, a visual (search) task, or a cognitive (arithmetic) task following the administration of alcohol (0%, 0.02%, and 0.05% BAC). Subjective ratings of intoxication and balance impairment increased in a dose-dependent manner in both novice and experienced motorcycle riders, while a BAC of 0.05%, but not 0.02%, was associated with impairments in static balance ability. This balance impairment was exacerbated when riders performed a cognitive, but not a visual, secondary task. Likewise, 0.05% BAC was associated with impairments in novice and experienced riders' performance of a cognitive, but not a visual, secondary task, suggesting that interactive processes underlie balance and cognitive task performance. There were no observed differences between novice vs. experienced riders on static balance and secondary task performance, either alone or in combination. Implications for road safety and future 'drink riding' policy considerations are discussed.

Adrenarche and middle childhood

Middle childhood, the period from 6 to 12 years of age, is defined socially by increasing autonomy and emotional regulation, somatically by the development of anatomical structures for subsistence, and endocrinologically by adrenarche, the adrenal production of dehydroepiandrosterone (DHEA). Here I suggest that DHEA plays a key role in the coordinated development of the brain and body beginning with middle childhood, via energetic allocation. I argue that with adrenarche, increasing levels of circulating DHEA act to down-regulate the release of glucose into circulation and hence limit the supply of glucose which is needed by the brain for synaptogenesis. Furthermore, I suggest the antioxidant properties of DHEA may be important in maintaining synaptic plasticity throughout middle childhood within slow-developing areas of the cortex, including the insula, thamalus, and anterior cingulate cortex. In addition, DHEA may play a role in the development of body odor as a reliable social signal of behavioral changes associated with middle childhood.

Applying motor-control theory to physical therapy practice: a case report

PURPOSE

This case report describes the application of an integrated, systems-based theory of motor control to physical therapy practice.Client Description: The patient was a 5-year-old boy with spastic hemiplegic cerebral palsy who was entering kindergarten. Parent concerns related to the child's safety in playground activities such as playing on the slide.

INTERVENTIONS

Motor-control theory, including factors related to the task, the environment, and the individual, was used to guide and direct physical therapy management related to the patient goal of safely and effectively climbing the ladder to the playground slide.Patient Outcomes: When the child entered kindergarten, he was able to safely ascend the ladder to the playground slide, using a modified movement pattern, when distractions were minimized. However, attentional issues continued to affect task execution when other children were present.

IMPLICATIONS

This case report demonstrates a means by which current knowledge and theory can be integrated into clinical practice.

FUTURE DIRECTIONS

Applying motor-control theory to this case led to the development of clinical questions for future research.

Development of postural control during gait in typically developing children: the effects of dual-task conditions

The purpose of this study was to investigate the typical development of postural control in younger (5-6 yrs) and older (7-16 yrs) children (YTD and OTD) during two gait tasks, including level walking and obstacle-crossing, using a dual-task paradigm, and to compare the results of the children's performance with that of healthy young adults (HYA). Our findings revealed that gait control in typical children requires attentional resources to maintain stability. Moreover, dual-task interference was less in HYA compared to YTD and OTD. Gait performance decrements in the dual-task context were greater in YTD compared to OTD, whereas cognitive performance decrements in YTD and OTD were similar. In addition, dual-tasking affected cognitive performance more in YTD when gait task difficulty was increased. Results suggest a developmental trend in attentional resources used to control gait in typical children. Postural control during gait under dual-task conditions was improved when children were more mature, as attentional resources increased with age.

Behavioral data and neural correlates for postural prioritization and flexible resource allocation in concurrent postural and motor tasks

This study was undertaken to investigate the reciprocity effect between postural and suprapostural performances and its underlying neural mechanisms wherein subjects executed a perceptual-motor suprapostural task and maintained steady upright postures. Fourteen healthy individuals conducted force-matching maneuvers (static vs. dynamic) under two stance conditions (bipedal stance vs. unipedal stance); meanwhile, force-matching error, center of pressure dynamics, event-related potentials (ERPs), and the movement-related potential (MRP) were monitored. The behavioral results showed that force-matching error and postural sway were differently modulated by variations in stance pattern and force-matching version. Increase in postural challenge undermined the precision of static force-matching but facilitated a dynamic force-matching task. Both static and dynamic force-matching tasks improved postural control of unipedal stance but not of bipedal stance, in reference to the control conditions. ERP results revealed a stance-dependent N1 response, which was greater around the parietal cortex in the unipedal stance conditions. Instead, P2 was modulated by the effect of the suprapostural motor task, with a smaller P2 in the right parietal cortex for dynamic force-matching. Spatiotemporal evolution of the MRP commenced at the left frontal-central area and spread bilaterally over the frontal-central and parietal cortex. MRP onset was subject to an analogous interaction effect on force-matching performance. Our findings suggest postural prioritization and a structural alternation effect of stance pattern on postural performance, relevant to implicit expansion and selective allocation of central resources for relative task-loads of a postural-suprapostural task.

A neurocognitive perspective on developmental disregard in children with hemiplegic cerebral palsy

A common problem in children with hemiplegic cerebral palsy (CP) is the asymmetrical development of arm and hand capacity caused by the lack of use of the affected upper limb, or developmental disregard. In this paper, we provide a neuropsychological model that relates developmental disregard to attentional processes and motor learning. From this model, we hypothesize that high attentional demands associated with the use of the affected upper limb might hinder its use in daily life, and therefore may be a factor in developmental disregard. This can be assessed with a dual-task paradigm. However, until now, this has not been applied to children with CP. We provide recommendations for using a dual-task paradigm in children with CP based on empirical studies in typically developing children and children with developmental coordination disorder. Ultimately, these dual-task studies may be used to improve interventions aimed at reducing developmental disregard.

The interrelation between cognitive and motor development in typically developing children aged 4-11 years is underpinned by visual processing and fine manual control

We charted the interrelation between cognitive and motor skills in typically developing children aged 4-11 years across broad ability measures from standardized tests and investigated the nature of this relationship by examining effects of age and sex. Results indicated a significant, moderate correlation between gross cognitive and motor scores across all participants. Correlations between indices of the standardized measures and a principal component analysis revealed that visual processing (VP) and fine manual control (FMC) largely accounted for the interrelation between the overall domains. Age and sex affected the strength of gross correlation: 7-year-olds showed a weaker correlation than all other ages and females exhibited a significantly stronger correlation than males. However, the correlation between VP and FMC was constant across all age and sex groups, except 4-year-old males. These findings advance evidence that from an early age, cognitive and motor development is linked by elucidating the underlying nature of this relationship. These results have important implications for clinical, educational, and experimental practice.

Effects of a secondary task on postural control in children with Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder characterized by involuntary motor and vocal tics. Sub-clinical postural control anomalies have recently been reported in children with TS. The goal of the present study was to determine whether these anomalies interact with attention in postural control. Thirty-two younger (below 10 years) and 21 older (above 10 years) children with TS were compared to 13 younger and 15 older age-matched controls. Postural control was examined during standing with and without a secondary visual attention task. Sway velocity was higher in younger children than older ones and also higher in children with TS than in controls. The secondary task exacerbated the velocity anomalies in younger children with TS. The effects were independent of tic severity, medication, and attention deficit. The results suggest that postural control anomalies in TS are sensitive to attentional requirements.