Postural strategies and sensory integration: no turning point between childhood and adolescence

Quantitative Gait and Balance Outcomes for Ataxia Trials: Consensus Recommendations by the Ataxia Global Initiative Working Group on Digital-Motor Biomarkers

With disease-modifying drugs on the horizon for degenerative ataxias, ecologically valid, finely granulated, digital health measures are highly warranted to augment clinical and patient-reported outcome measures. Gait and balance disturbances most often present as the first signs of degenerative cerebellar ataxia and are the most reported disabling features in disease progression. Thus, digital gait and balance measures constitute promising and relevant performance outcomes for clinical trials.This narrative review with embedded consensus will describe evidence for the sensitivity of digital gait and balance measures for evaluating ataxia severity and progression, propose a consensus protocol for establishing gait and balance metrics in natural history studies and clinical trials, and discuss relevant issues for their use as performance outcomes.

Postural adjustments preceding string release in trained archers

Optimal postural stability is required to perform in archery. Since the dynamic consequences of the string release may disturb postural equilibrium, they should be integrated into an archer motor programme to optimize postural stability. This study aimed to characterize the postural strategy archers use to limit the potentially detrimental impact of the bow release on their postural stability and identify characteristics that may explain a better performance. Six elite and seven sub-elite archers performed a series of 18 shots at 70 metres, standing on two force plates. Postural stability indicators were computed during the aiming and the shooting phase using the trajectory of the centre of pressure. Two postural strategies were defined, as whether they were triggered before (early) or after (late) the string release time. Both groups used anticipated postural adjustments, but elite archers triggered them before the string release more often and sooner. Scores differed between the two groups, but no differences were found between early and late shots. Trained archers seem to have finely integrated the dynamic consequences of their bow motion, triggering anticipated postural adjustments prior to the string release. However, it remains unclear whether this anticipation can positively influence the performance outcome.

Mediolateral Postural Control Mechanisms and Proprioception Improve With Kicking Sports Training During Adolescence

Sensorimotor stimulation during the sensitive period is crucial for proper brain development. Kicking sports (KS) training stimulates these sensorimotor functions. The purpose of this study was to investigate if incorporating specific sensorimotor stimulation in mediolateral axis and proprioceptive inputs during KS training will improve the specific sensorimotor performance in adolescents. We assessed stability limits in 13 KS practitioners and 20 control participants. Starting from an upright position, subjects were asked to lean as far as possible (forward, backward, rightward, and leftward). Three sensory conditions were tested: (1) eyes open, (2) eyes closed, and (3) eyes closed while standing on a foam mat. We analyzed the maximal center of pressure excursion and the root means square of the center of pressure displacements. Results showed that KS group had smaller root means square and larger maximal center of pressure excursions than those of control participants in mediolateral axis in all sensory conditions. Furthermore, the results also revealed a significant smaller root means square excursion in KS group under foam mat condition compared to control group ML axis. This study provides evidence that KS training improved the lateral balance control and proprioceptive integration.

Adolescents running in conventional running shoes have lower vertical instantaneous loading rates but greater asymmetry than running barefoot or in partial-minimal shoes

Footwear may moderate the transiently heightened asymmetry in lower limb loading associated with peak growth in adolescence during running. This repeated-measures study compared the magnitude and symmetry of peak vertical ground reaction force and instantaneous loading rates (VILRs) in adolescents during barefoot and shod running. Ten adolescents (age, 10.6 ± 1.7 years) ran at self-selected speed (1.7 ± 0.3 m/s) on an instrumented treadmill under three counter-balanced conditions; barefoot and shod with partial-minimal and conventional running shoes. All participants were within one year of their estimated peak height velocity based on sex-specific regression equations. Foot-strike patterns, peak vertical ground reaction force and VILRs were recorded during 20 seconds of steady-state running. Symmetry of ground reaction forces was assessed using the symmetry index. Repeated-measures ANOVAs were used to compare conditions (α=.05). Adolescents used a rearfoot foot-strike pattern during barefoot and shod running. Use of conventional shoes resulted in a lower VILR (P < .05, dz = 0.9), but higher VILR asymmetry (P < .05) than running barefoot (dz = 1.5) or in partial-minimal shoes (dz = 1.6). Conventional running shoes result in a lower VILR than running unshod or in partial-minimal shoes but may have the unintended consequence of increasing VILR asymmetry. The findings may have implications for performance, musculoskeletal development and injury in adolescents.

Postural control in adolescent boys and girls before the age of peak height velocity: Effects of task difficulty

BACKGROUND

Adolescent children experience a critical developmental period marked by rapid biological changes. Research question To describe the longitudinal changes in postural control that occur in adolescent boys and girls before the age of peak height velocity (PHV).

METHODS

Here, to address the gap of knowledge, we compared the postural control and activation strategies of the muscles that control the ankle joint in twenty-three boys (age 12.5 ± 0.29) and twenty-one girls (age 10.5 ± 0.32). They performed easy (two legs) and difficult (two legs-eyes closed; one leg) postural balance tasks at 18 and 9 months before PHV and at PHV. We quantified the center of pressure (COP) displacements in the anterior-posterior (AP) and mediolateral (ML) directions and electromyographic (EMG) activity of tibialis anterior (TA) and medial gastrocnemius (MG) muscles.

RESULTS

Boys exhibited greater AP and ML COP displacement than girls only for the one leg task (difficult task). Although boys and girls had similar postural control 18 months prior to PHV, girls exhibited lesser COP displacement at 9 months before PHV, which related to greater TA-MG coactivation (R² = 0.26; p < 0.01). In contrast, postural control was not different between boys and girls with an easy balance task (two legs) performed with eyes open and closed. Rather, we found that all children improved their COP displacement in the ML direction with maturity and both AP and ML COP was significantly lower with eyes open.

CONCLUSION

These findings provide novel evidence that postural control is superior in early adolescent girls than boys 9 months prior to PHV, likely associated with an earlier maturation of muscle coordination.

Influence of visual control on the quality of graphic gesture in children with handwriting disorders

Handwriting disorders (HD) are considered one of the major public health problems among school-aged children worldwide with significant interference on academic performances. The current study hypothesized that HD could be partly explained by a deficit in sensory feedback processing during handwriting. To explore this hypothesis, we have analyzed the effect of vision suppression on postural-gestural and on spatial/temporal/kinematic organization of drawing during an early pre-scriptural loop task with a digital pen, under two conditions: eyes open and eyes closed. Data collected from 35 children with HD were compared to data collected from typical children (typical group) from primary schools. The HD group showed significantly poorer postural control and an improvement on the spatial/temporal/kinematic organization of drawings when they closed their eyes compared to eyes opened. While in the typical group, postural-gestural organization became significantly more mature but there was no significant influence found on spatial/temporal/kinematic parameters of the loops. Thus, handwriting disorders could be explained by both proprioceptive/kinesthetic feedback disabilities and a disruptive effect of the visual control on the quality of the pre-scriptural drawings among these children who have kinesthetic memory and visuospatial disabilities. The ability of directing the strokes would remain dependent on sensory feedbacks, themselves insufficiently efficient, which would lead to difficulties in reaching a proactive control of handwriting. This current research is a liable contribution to enhance clinical practice, useful in clinical decision-making processes for handwriting disorders remediation.

Normative database of postural sway measures using inertial sensors in typically developing children and young adults

OBJECTIVE

Reference values utilizing the APDM MobilityLab® inertial sensor system have not been established in children and young adults ages 5-30. These values are necessary for clinicians and researchers to compare to children with balance impairments.

METHODS

A group of 144 typically developing children and young adults from age 5-30 years completed the instrumented SWAY test during 6 test conditions: normal stance, firm surface, eyes open (EO) and closed (EC); normal stance, foam surface, EO and EC; and tandem stance, firm surface, EO and EC. Selected variables for normative outcomes included total sway area, and the mean, sagittal and coronal values for RMS sway, jerk, sway velocity and path length. Sex differences were examined within age groups via t tests. The effect of age on postural sway variables was analyzed using a one-way ANOVA for the mean values of total sway area, RMS sway, velocity and jerk, followed by post-hoc pairwise comparisons.

RESULTS

All sway parameters decreased significantly with age (p < 0.0001). Adult-like total sway area and jerk were achieved by ages 9-10 except for jerk during EC on foam. RMS sway and sway velocity reached adult levels by ages 11-13 during all EO and tandem stance conditions, and 14-21 with EC during normal stance on firm and foam surfaces for RMS sway and EC on firm surfaces for velocity. Females ages 5-6 performed more poorly during EO firm and EC foam for certain variables, but better during EO tandem and females ages 7-13 outperformed males when sex differences were found.

SIGNIFICANCE

These reference values can now be used by clinicians and researchers to evaluate abnormal postural sway and response to interventions in children and young adults.

Immersive virtual reality interferes with default head-trunk coordination strategies in young children

The acquisition of postural control is an elaborate process, which relies on the balanced integration of multisensory inputs. Current models suggest that young children rely on an 'en-block' control of their upper body before sequentially acquiring a segmental control around the age of 7, and that they resort to the former strategy under challenging conditions. While recent works suggest that a virtual sensory environment alters visuomotor integration in healthy adults, little is known about the effects on younger individuals. Here we show that this default coordination pattern is disrupted by an immersive virtual reality framework where a steering role is assigned to the trunk, which causes 6- to 8-year-olds to employ an ill-adapted segmental strategy. These results provide an alternate trajectory of motor development and emphasize the immaturity of postural control at these ages.

Hand size representation in healthy children and young adults

Whereas we experience our body as a coherent volumetric object, the brain appears to maintain highly fragmented representations of individual body parts. Little is known about how body representations of hand size and shape are built and evolve during infancy and young adulthood. This study aimed to investigate the effect of hand side, handedness, and age on the development of central hand size representation. The observational study with comparison groups was conducted with 90 typically developing Belgian school children and young adults (48 male and 42 female; age range = 5.0-23.0 years; 49 left-handed and 41 right-handed). Participants estimated their hand size and shape using two different tasks. In the localization task, participants were verbally cued to judge the locations of 10 anatomical landmarks of an occluded hand. An implicit hand size map was constructed and compared with actual hand dimensions. In the template selection task, the explicit hand shape was measured with a depictive method. Hand shape indexes were calculated and compared for the actual, implicit, and explicit conditions. Participants were divided into four age groups (5-8 years, 9-10 years, 11-16 years, and 17-23 years). Implicit hand maps featured underestimation of finger length and overestimation of hand width, which is already present in the youngest children. Linear mixed modeling revealed no influence of hand side on finger length underestimation; nonetheless, a significant main effect of age (p = .001) was exposed. Sinistrals aged 11 to 16 years showed significantly less underestimation (p = .03) than dextrals of the same age. As for the hand shape, the implicit condition differed significantly with the actual and explicit conditions (p < .001). Again, the implicit shape index was subjected to handedness and age effects, with significant differences being found between sinistrals and dextrals in the age groups of 9 and 10 years (p = .029) and 11 to 16 years (p < .001). In conclusion, the implicit metric component of the hand representation in children and young adults is misperceived, featuring shortened fingers and broadened hands since a very young age. Crucially, the finger length underestimation increases with age and shows a different developmental trajectory for sinistrals and dextrals. In contrast, the explicit hand shape is approximately veridical and seems immune from age and handedness effects. This study confirms the dual character of somatoperception and establishes a point of reference for children and young adults.

Neuromuscular performance of balance and posture control in childhood and adolescence

This study examined a potential age-dependency of both posture and stability (balance) control in children and adolescents in a healthy population. Body posture with open and closed eyes was examined for a total of 456 test persons (age 6.7–17.6 years. Posture parameters (posture index, upper body tilt, trunk tilt) were assessed in the sagittal plane. Additionally, the oscillation of the center of pressure with open and closed eyes was additionally analyzed in a sub-sample of 318 subjects.

Absolute values of stability control parameters changed significantly during childhood and adolescence for both boys (p = 0.005) and girls (p = 0.01). Relative changes of stability and posture parameters when closing the eyes did not change (p > 0.05) and were independent of age, gender or sports activity in healthy children and adolescents.

The shifting of the body segments towards each other, as a result of the loss of visual information, does not seem to be primarily responsible for the increase in COP fluctuation. This is a further indication that stability control and posture control are complex interdependent mechanisms whose interaction is not yet fully understood.

How do children aged 6 to 11 stabilize themselves on an unstable sitting device? The progressive development of axial segment control

Postural control continues to develop during middle childhood as shown by the decrease in body sway in stance between the ages of 5 and 11. Although head and trunk control is crucial for balance control during both static and dynamic activities, evaluating its specific development and its contribution to overall postural control is methodologically challenging. Here, we used an unstable sitting device adapted to ensure that only the axial segments could control the balance of the device and thus the balance of the upper body. This study aimed to assess the development of the postural stabilization of axial body segments during middle childhood. Thirty-six children (in three age groups: 6-7yo, 8-9yo, and 10-11yo) and 11 adults sat on the unstable sitting device and had to stabilize their axial segments under several conditions: a moderate vs. high level of balance challenge, and eyes open vs. eyes closed. Upper-body postural sway (area, mean velocity and root mean square (RMS) of the center of pressure (CoP) displacement) decreased progressively with age (6-7yo > 8-9yo > 10-11yo > adults), and this effect was accentuated when the balance challenge was high (for CoP area) or in the "eyes closed" condition (for CoP area and RMS). The stabilization strategies were assessed by anchoring indexes computed from three-dimensional kinematics. A progressive shift was showed, from an "en bloc" pattern at 6-7 years of age toward a more articulated (i.e. adult-like) pattern at 10-11. A head-on-space stabilization strategy first emerged at the age of 8-9. Middle childhood is an important period for the development of axial segment stabilization, which continues to mature until adulthood. This development might be related to the introduction and progressive mastery of feedforward sensorimotor processes and might contribute strongly to the development of overall postural control.

Effects of head motion on postural stability in healthy young adults with chronic motion sensitivity

Background

Motion sensitivity, or motion sickness, is common in modern vehicular and visually stimulating environments. Several studies have shown a relationship between motion sensitivity and decreased postural stability. We aimed to evaluate the effects of head motion (horizontal and vertical) on postural stability in healthy adults with and without chronic motion sensitivity (CMS).

Methods

Sixty healthy adult men and women (age, 20–40 years) with CMS (CMS group, n = 30) and without CMS (non-CMS group, n = 30) participated in the study. Postural stability was assessed during three conditions (static, horizontal head motion, and vertical head motion) using computerized dynamic posturography. Group and condition-related differences in equilibrium scores were evaluated.

Results

There was no significant group x condition interaction (F_2,114 = 0.9, partial ƞ² = 0.04, p = 0.35). However, significant condition-related differences in equilibrium scores were observed (F_2,114 = 26.4, partial ƞ² = 0.31, p < 0.001). Equilibrium scores were significantly worse in the horizontal and vertical head motion conditions compared to those in the static condition (p < 0.001), but were comparable in vertical and horizontal head motion conditions (p = 0.27).

Conclusions

Postural stability was lower in the horizontal and vertical conditions compared to the static condition. However, horizontal and vertical head motions had comparable effects on postural stability in both CMS and non-CMS groups, contrary to our expectations.

Adolescent Awkwardness: Alterations in Temporal Control Characteristics of Posture with Maturation and the Relation to Movement Exploration

A phenomenon called adolescent awkwardness is believed to alter motor control, but underlying mechanisms remain largely unclear. Since adolescents undergo neurological and anthropometrical changes during this developmental phase, we hypothesized that adolescents control their movements less tightly and use a different coordinative structure compared to adults. Moreover, we tested if emerging differences were driven by body height alterations between age groups. Using 39 reflective markers, postural movements during tandem stance with eyes open and eyes closed of 12 adolescents (height 168.1 ± 8.8 cm) and 14 adults were measured, in which 9 adults were smaller or equal than 180 cm (177.9 ± 3.0 cm) and 5 taller or equal than 190 cm (192.0 ± 2.5 cm). A principal component analysis (PCA) was used to extract the first nine principal movement components (PMk). The contribution of each PMk to the overall balancing movement was determined according to their relative variance share (rVARk) and tightness of motor control was examined using the number of times that the acceleration of each PMk changed direction (Nk). Results in rVARk did not show significant differences in coordinative structure between adolescents and adults, but Nk revealed that adolescents seem to control their movements less tightly in higher-order PMk, arguably due to slower processing times and missing automatization of postural control or potential increases in exploration. Body height was found to not cause motor control differences between age groups.

Obesity Affects Postural Control in Middle Childhood and Adolescence but not in Early Childhood

Introduction: Overweight/obese children have postural control differences compared with normal-weight children. Nevertheless, there are not studies that analyze the effect of obesity during the entire period comprised between childhood and adolescence. The objective of this study was to determine the differences in postural control between normal-weight and overweight/obese participants during early and middle childhood and adolescence. Methods: 359 children were divided into six groups according to age and weight status. Each participant carried out one 30-s trial with eyes open (EO) and one 30-s trial with eyes closed (EC). Center of pressure signals were acquired using a Wii Balance Board. Mean velocity in antero-posterior (MVAP) and medio-lateral (MVML) directions and the 95% confidence interval ellipse area were calculated. Results: A Mann Whitney U-test showed significant differences between normal-weight and obese 8- to 12-year-old children in MVAP and MVML in both EO and EC. In 13- to 17-year-old adolescents, there were differences between normal-weight and overweight/obese in ellipse area and MVML, both in EO and EC condition. There were no differences in postural stability between normal-weight and overweight/obese 4- to 7-year-old children. Conclusions: Obesity reduces postural stability only in middle childhood and adolescence but not in early childhood.

Age and sex differences in human balance performance from 6-18 years of age: A systematic review and meta-analysis

Background

The process of growing leads to inter-individual differences in the timing of growth, maturational, and developmental processes during childhood and adolescence, also affecting balance performance in youth. However, differences in balance performance by age and sex in youth have not been systematically investigated yet.

Objective

The objective of the present study was to characterize and quantify age- and sex-related differences in balance performance in healthy youth.

Methods

A computerized systematic literature search was performed in the electronic databases PubMed, Web of Science, and SPORTDiscus. To be applicable for analysis, studies had to report at least one measure of static steady-state, dynamic steady-state, proactive or reactive balance in healthy children (6–12 years) and/or adolescents (13–18 years). Coding of the studies was done according to the following criteria: age, sex, and balance outcome. Study quality was assessed using the Appraisal tool for Cross-Sectional Studies. Weighted standardized mean differences were calculated and classified according to their magnitude.

Results

Twenty-one studies examined age-related differences in balance performance. A large effect for measures of static steady-state balance (SMD_ba = 1.20) and small effects for proxies of dynamic steady-state (SMD_ba = 0.26) and proactive balance (SMD_ba = 0.28) were found; all in favor of adolescents. Twenty-five studies investigated sex-related differences in balance performance. A small-sized effect was observed for static steady-state balance (SMD_bs = 0.33) in favor of girls and for dynamic steady-state (SMD_bs -0.02) and proactive balance (SMD_bs = -0.15) in favor of boys. Due to a lack of studies, no analysis for measures of reactive balance was performed.

Conclusions

Our systematic review and meta-analysis revealed better balance performances in adolescents compared to children, irrespective of the measure considered. Sex-related differences were inconsistent. These findings may have implications for example in terms of trainability of balance in youth that should be investigated in future studies.

Targeted Athletic Training Improves the Neuromuscular Performance in Terms of Body Posture From Adolescence to Adulthood - Long-Term Study Over 6 Years

Poor posture in childhood and adolescence is held responsible for the occurrence of associated disorders in adult age. This study aimed to verify whether body posture in adolescence can be enhanced through the improvement of neuromuscular performance, attained by means of targeted strength, stretch, and body perception training, and whether any such improvement might also transition into adulthood. From a total of 84 volunteers, the posture development of 67 adolescents was checked annually between the age of 14 and 20 based on index values in three posture situations. 28 adolescents exercised twice a week for about 2 h up to the age of 18, 24 adolescents exercised continually up to the age of 20. Both groups practiced other additional sports for about 1.8 h/week. Fifteen persons served as a non-exercising control group, practicing optional sports of about 1.8 h/week until the age of 18, after that for 0.9 h/week. Group allocation was not random, but depended on the participants’ choice. A linear mixed model was used to analyze the development of posture indexes among the groups and over time and the possible influence of anthropometric parameters (weight, size), of optional athletic activity and of sedentary behavior. The post hoc pairwise comparison was performed applying the Scheffé test. The significance level was set at 0.05. The group that exercised continually (TR20) exhibited a significant posture parameter improvement in all posture situations from the 2nd year of exercising on. The group that terminated their training when reaching adulthood (TR18) retained some improvements, such as conscious straightening of the body posture. In other posture situations (habitual, closed eyes), their posture results declined again from age 18. The effect sizes determined were between η² = 0.12 and η² = 0.19 and represent moderate to strong effects. The control group did not exhibit any differences. Anthropometric parameters, additional athletic activities and sedentary behavior did not influence the posture parameters significantly. An additional athletic training of 2 h per week including elements for improved body perception seems to have the potential to improve body posture in symptom free male adolescents and young adults.

Visual dependence affects postural sway responses to continuous visual field motion in individuals with cerebral palsy

The current study aimed to explore the impact of visual dependence on sensorimotor coupling of postural sway and visual motion in adults and teens with spastic cerebral palsy (CP). We hypothesized that individuals with CP would exhibit greater magnitudes of sway than healthy individuals, and the presence of visual dependence (VD) would produce instability in the direction of visual motion. Participants stood in a virtual environment in which the visual scene remained static or continuously rotated 30 degree/second in pitch-up or pitch-down. Increased center of pressure and center of mass responses were observed in the direction of visual scene motion in those with CP. Those with VD exhibited reduced frequency responses in anterior-posterior direction than those who were visually independent. VD suggests deficient sensorimotor integration that could contribute to postural instability and reduced motor function. Individuals with CP who are visually dependent may benefit from more sensory focused rehabilitation strategies.

ABBREVIATIONS

AP, anterior-posterior; CP, cerebral palsy; COM, center of mass; COP, center of pressure; MDF, median frequency; ML, mediolateral; PD, pitch down (nose down) rotation; PU, pitch up (nose up) rotation; RFT, rod and frame test; RMS, root mean square; SLP, slope of the fitted line; TD, typical development; VD, visual dependence; VI, visual independence; VOR, vestibulo-ocular reflex; VPI, visual perceptual impairment.

Changes of spatial and temporal characteristics of dynamic postural control in children with typical neurodevelopment with age: Results of a multicenter pediatric study

BACKGROUND

The aim of this multicenter study is to investigate the effect of chronological age and gender in postural control.

METHODS

To approach an ecological model, we used a multicenter posturography assessment. We analyzed postural control with surface, mean velocity of center of pressure [CoP] and temporal analysis, with Postural Instability Index [PII] being a more sensitive parameter in postural evaluation. A large sample of 156 age- and gender-matched healthy children recruited in several pediatrics hospitals, participated.

RESULTS

Our current results showed a significant decrease of all postural parameters (surface, mean velocity of CoP and PII) with age, and only on stable support condition. Our study additionally described a gender effect in conditions where all sensory inputs are most challenged with a mean velocity of CoP being significantly smaller in girls with respect to boys.

CONCLUSION

We concluded that postural control improves with age linked with maturation process. Moreover, this maturation process seems not yet achieved at 16.08 years and still ongoing beyond. Interestingly, our result reported specificities linked with gender effect. Indeed, girls and boys do not proceed in the same way to maintain their postural control. We could make hypothesis that more children maintain their postural control efficiently; with a low energy cost, the more they could allocate attention to learning during childhood.

Cerebellar motor syndrome from children to the elderly

More than a century after the description of its cardinal components, the cerebellar motor syndrome (CMS) remains a cornerstone of daily clinical ataxiology, in both children and adults. Anatomically, motor cerebellum involves lobules I-V, VI, and VIII. CMS is typically associated with errors in the metrics of voluntary movements and a lack of coordination. Symptoms and motor signs consist of speech deficits, impairments of limb movements, and abnormalities of posture/gait. Ataxic dysarthria has a typical scanning (explosive with staccato) feature, voice has a nasal character, and speech is slurred. Cerebellar mutism is most common in children and occurs after resection of a large midline cerebellar tumor. Ataxia of limbs includes at various degrees dysmetria (hypermetria: overshoot, hypometria: undershoot), dysdiadochokinesia, cerebellar tremor (action tremor, postural tremor, kinetic tremor, some forms of orthostatic tremor), isometrataxia, disorders of muscle tone (both hypotonia and cerebellar fits), and impaired check and rebound. Handwriting is irregular and some patients exhibit megalographia. Cerebellar patients show an increased body sway with a broad-based stance (ataxia of stance). Gait is irregular and staggering. Delayed learning of complex motor skills may be a prominent feature in children. CMS is currently explained by the inability of the cerebellum to handle feedback signals during slow movements and to create, store, select, and update internal models during fast movements. The cerebellum is embedded in large-scale brain networks and is essential to perform accurate motor predictions related to body dynamics and environmental stimuli. Overall, the observations in children and adults exhibiting a CMS fit with the hypothesis that the cerebellum contains neural representations reproducing the dynamic properties of body, and generates and calibrates sensorimotor predictions. Therapies aiming at a reinforcement or restoration of internal models should be implemented to cancel CMS in cerebellar ataxias. The developmental trajectory of the cerebellum, the immature motor behavior in children, and the networks implicated in CMS need to be taken into account.

Development of postural control and maturation of sensory systems in children of different ages a cross-sectional study

OBJECTIVE

To evaluate the stability, postural adjustments and contributions of sensory information for postural control in children.

METHODS

40 boys and 40 girls were equally divided into groups of 5, 7, 9 and 12 years (G5, G7, G9 and G12). All children were submitted to dynamic posturography using a modified sensory organization test, using four sensory conditions: combining stable or sway referencing platform with eyes opened, or closed. The area and displacements of the center of pressure were used to determine stability, while the adjustments were used to measure the speed of the center of pressure displacements. These measurements were compared between groups and test conditions.

RESULTS

Stability tends to increase with age and to decrease with sensory manipulation with significant differences between G5 and G7 in different measures. G7 differed from G12 under the conditions of stable and sway platform with eyes open. G9 did not differ from G12. Similar behavior was observed for adjustments, especially in anterior-posterior directions.

CONCLUSION

Postural stability and adjustments were associated with age and were influenced by sensory manipulation. The ability to perform anterior-posterior adjustments was more evident and sensory maturation occurred firstly on the visual system, then proprioceptive system, and finally, the vestibular system, reaching functional maturity at nine years of age. Seven-year-olds seem to go through a period of differentiated singularity in postural control.

Interrelationship between postural balance and body posture in children and adolescents

[Purpose] This study examined possible interrelationships between postural sway and posture parameters in children and adolescents with a particular focus on posture weakness. [Subjects and Methods] 308 healthy children and adolescents (124 girls, 184 boys, aged 12.3 ± 2.5 years) participated in the study. Posture parameters (posture index, head protrusion, trunk inclination) were determined based on posture photos in the sagittal plane. Postural sway was measured during 20 seconds on a force plate. The Pearson’s product-moment correlation coefficients between the anthropometric and posture parameters and the sway path length (SPL) were calculated, as well as the coefficient of determination R². [Results] There is a weak but significant correlation between age or body mass index of the test subjects and the SPL. There is no statistically significant correlation between posture parameters and the SPL. Children and adolescents with posture weakness do not exhibit a changed SPL. [Conclusion] Therefore, therapy of poor posture must be considered separately from therapeutic measures for the improvement of balance skills.

The developmental dynamics of gait maturation with a focus on spatiotemporal measures

Gait analysis is recognised as a powerful clinical tool for studying relationships between motor control and brain function. By drawing on the literature investigating gait in individuals with neurological disorders, this review provides insight into the neural processes that contribute to and regulate specific spatiotemporal sub-components of gait and how they may mature across early to late childhood. This review also discusses the roles of changing anthropomorphic characteristics, and maturing sensory and higher-order cognitive processes in differentiating the developmental trajectories of the sub-components of gait. Importantly, although studies have shown that cognitive-gait interference is larger in children compared to adults, the contributing neurocognitive mechanisms may vary across age groups who have different types of attentional or cognitive vulnerabilities. These findings have implications for current models of gait maturation by highlighting the need for a dynamic model that focuses on the integration of various factors that contribute to gait though experience and practice. This is essential to elucidating why gait and other motor deficits are often contiguous with cognitive neurodevelopmental disorders.

Decreased postural control in adult survivors of childhood cancer treated with chemotherapy

The objective of cancer treatment is to secure survival. However, as chemotherapeutic agents can affect the central and peripheral nervous systems, patients must undergo a process of central compensation. We explored the effectiveness of this compensation process by measuring postural behaviour in adult survivors of childhood cancer treated with chemotherapy (CTS). We recruited sixteen adults treated with chemotherapy in childhood for malignant solid (non-CNS) tumours and 25 healthy age-matched controls. Subjects performed posturography with eyes open and closed during quiet and perturbed standing. Repeated balance perturbations through calf vibrations were used to study postural adaptation. Subjects were stratified into two groups (treatment before or from 12 years of age) to determine age at treatment effects. Both quiet (p = 0.040) and perturbed standing (p ≤ 0.009) were significantly poorer in CTS compared to controls, particularly with eyes open and among those treated younger. Moreover, CTS had reduced levels of adaptation compared to controls, both with eyes closed and open. Hence, adults treated with chemotherapy for childhood cancer may suffer late effects of poorer postural control manifested as reduced contribution of vision and as reduced adaptation skills. These findings advocate development of chemotherapeutic agents that cause fewer long-term side effects when used for treating children.

Does somatosensation change with age in children and adolescents? A systematic review

BACKGROUND

Somatosensory modalities, such as touch, proprioception and haptic ability, greatly influence the achievement of developmental milestones for children. Describing somatosensory impairment, natural variability and typical or expected developmental changes across age groups will help establish frameworks for intervention in clinical populations. This systematic review aimed to determine how different somatosensory modalities develop across childhood into adolescence to use as a point of reference for children at risk of somatosensory impairment.

METHODS

Searches of five electronic databases were undertaken through EBSCO-host (MEDLINE, CINAHL, PsycINFO, SPORTDiscus and ERIC) for studies measuring at least one somatosensory modality in typically developing individuals between birth and 18 years and analysed by age. Characteristics of studies were collected including country of origin, sample size, demographics and outcome measure used. Quality assessment and data extraction were performed by two independent reviewers.

RESULTS

Twenty three cross-sectional studies were included from a total of 188 articles retrieved: 8 examined aspects of touch, 5 proprioception and 10 haptic ability. Variability of study designs and variation in assessment tools precluded any formal meta-analysis.

CONCLUSIONS

Somatosensation matures through childhood into adolescence; however, the present review found the pattern of somatosensory development varied depending on the assessment tool used and the aspect of somatosensation being measured, making it difficult to describe typical performance. There is a need for comprehensive assessment batteries to measure the somatosensation, including touch, proprioception and haptic ability, of children at risk of somatosensory impairment to aid in the development of effective interventions.

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.

Balance in subjects with congenital or early onset strabismus: Influence of age

Few studies have investigated the relationship between strabismus and balance, and those that do exist focused on patients within a limited age range, while no studies on possible age-related changes have yet been conducted. Therefore, the aim of our study was to investigate whether the balance strategies adopted by patients with congenital or early onset strabismus change with age. Forty strabismic patients and 36 healthy subjects were enrolled in the study. Both patients and healthy subjects were divided into three subgroups according to age (children, adolescents, and adults) and underwent a stabilometric evaluation. When we compared the whole group of strabismic patients with the group of healthy subjects, we found that the center of pressure area and the trunk oscillations in the former were significantly different from those in the latter; when we considered the three age groups separately, only values in children with strabismus were different from those in the age-matched control group of healthy subjects. Strabismus was found to affect balance in children by inducing a postural strategy characterized by a reduction in physiological trunk oscillations. Gaining a better insight into postural control in strabismic subjects and its evolution with age may be crucial to improving rehabilitation in such patients and planning tailored rehabilitation treatment.

Changes in Habitual and Active Sagittal Posture in Children and Adolescents with and without Visual Input - Implications for Diagnostic Analysis of Posture

INTRODUCTION

Poor posture in children and adolescents has a prevalence of 22-65% and is suggested to be responsible for back pain. To assess posture, photometric imaging of sagittal posture is widely used, but usually only habitual posture positions (resting position with minimal muscle activity) are analysed.

AIM

The objective of this study was 1) to investigate possible changes in posture-describing parameters in the sagittal plane, when the subjects changed from a habitual passive posture to an actively corrected posture, and 2) to investigate the changes in posture parameters when an actively corrected posture was to be maintained with closed eyes.

MATERIALS AND METHODS

In a group of 216 male children and adolescents (average 12.4 ± 2.5 years, range 7.0 - 17.6 years), six sagittal posture parameters (body tilt BT, trunk incline TI, posture index PI, horizontal distances between ear, shoulder and hip and the perpendicular to the ankle joint) were determined by means of photometric imaging in an habitual passive posture position, in an actively erect posture with eyes open, and in active stance with eyes closed. The change in these parameters during the transition between the posture positions was analysed statistically (dependent t-Test or Wilcoxon-Test) after Bonferroni correction (p<0.004).

RESULTS

When moving from a habitual passive to an active posture BT, TI, PI, dEar, dShoulder, and dHip decreased significantly(p< 0.004). When the eyes were closed, only the perpendicular distances (dEar, dShoulder, and dHip) increased significantly. The parameters that describe the alignment of the trunk sections in relation to each other (BT, TI, PI), remained unchanged in both actively regulated posture positions.

CONCLUSION

Changes in sagittal posture parameters that occur when a habitual passive posture switches into an active posture or when an active posture is to be maintained while the eyes are closed can be used for diagnostic purposes regarding poor posture and posture regulation.

Effects of cold water immersion on variables of balance in healthy subjects with open and closed eyes

AbstractIntroduction Cryotherapy is the use of cold as therapeutic approach. Although often used, its impact on the postural balance is not well-known.Objectives To analyze the effects of cold water immersion in the postural balance on single-leg balance in healthy subjects through the variables of center-of-pressure, velocity anteroposterior and medial-lateral oscillations, comparing conditions open and closed eyes in the moments before, immediately, 20 and 40 minutes after cold water immersion.Material and methods Cross-sectional study with 30 male subjects, cold water immersion at 5 °C during 15 minutes assessed in a force platform, protocol of 3 trials of 30 seconds each with 10 seconds of rest, the average of the 3 trials was used for analysis. The software GraphPad Prisma 5.0 was used for statistical analysis, with the ANOVA test for repeated measures and comparisons with test of Friedman and post-test of Dunn.Results It was observed improvement of the balance by the results of the following variables: in the condition Open Eyes (OE) it was observed significant difference only in the velocity anteroposterior (AP) in the moment before immersion when compared to the 40-minute moment. Significant differences were observed in the condition Closed Eyes (CE) in the following comparisons: in the Center-of-Pressure (COP) only at the immediate moment when compared to the 40-minute moment; in the velocity AP in the moment before when compared to the 40-minute moment, in the immediate moment when compared to the 20-minute and 40-minute moments; and in the medial-lateral velocity (Vel-ML) in two comparisons: in the moment before immersion when compared to the 20-minute and 40-minute moments after cryotherapy. Results show safety in performing activities after cryotherapy.Conclusion Improvement of the postural balance after cold water immersion on the predetermined conditions of this study.

Adolescent idiopathic scoliosis and spinal fusion do not substantially impact on postural balance

BACKGROUND

The spinal curvature in patients with Adolescent Idiopathic Scoliosis (AIS) causes an asymmetry of upper body postural alignment, which might affect postural balance. However, the currently available studies on balance in AIS patients are not consistent. Furthermore, it is not known whether potential deficits are similar between patients with single and double curves. Finally, the effects of a corrective posterior spinal fusion on postural balance have not yet been well established.

METHODS

Postural balance was tested on a force plate, in 26 female subjects with AIS (12-18 years old; preoperative Cobb-angle: 42-71°; single curve n = 18, double curve n = 6) preoperatively, at 3 months and 1 year postoperatively. We also conducted a balance assessment in 18 healthy age-matched female subjects. Subjects were tested during quiet double-leg standing in four conditions (eyes open/closed; foam/solid surface), while standing on one leg, while performing a dynamic balance (weight shifting) task and while performing a reaching task in four directions.

RESULTS

AIS subjects did not demonstrate greater COP velocities than controls during the double-leg standing tasks. In the reaching task, however, they achieved smaller COP displacements than healthy controls, except in the anterior direction. AIS patients with double curves had significantly greater COP velocities in all test conditions compared to those with a single curve (p < 0.05). For the AIS group, a slight increase in COP velocities was observed in the foam eyes closed and right leg standing condition at 3 months post surgery. At 1-year post surgery, however, there were no significant differences in any of the outcome measures compared to the pre-surgery assessment, irrespective of the curve type.

CONCLUSIONS

Postural balance in AIS patients scheduled for surgery was similar to healthy age matched controls, except for a poorer reaching capacity. The latter finding may be related to their reduced range of motion of the spine. Patients with double curves demonstrated poorer balance than those with a single curve, despite the fact that they have a more symmetrical trunk posture. Postural balance one year after surgery did not improve as a result of the better spinal alignment, neither did the reduced range of trunk motion inherent to fusion negatively affect postural balance.

Subjective visual vertical and postural capability in children born prematurely

Purpose

We compared postural stability and subjective visual vertical performance in a group of very preterm-born children aged 3-4 years and in a group of age-matched full-term children.

Materials and Methods

A platform (from TechnoConcept) was used to measure postural control in children. Perception of subjective visual vertical was also recorded with posture while the child had to adjust the vertical in the dark or with visual perturbation. Two other conditions (control conditions) were also recorded while the child was on the platform: for a fixation of the vertical bar, and in eyes closed condition.

Results

Postural performance was poor in preterm-born children compared to that of age-matched full-term children: the surface area, the length in medio-lateral direction and the mean speed of the center of pressure (CoP) were significantly larger in the preterm-born children group (p < 0.04, p < 0.01, and p < 0.04, respectively). Dual task in both groups of children significantly affected postural control. The subjective visual vertical (SVV) values were more variable and less precise in preterm-born children.

Discussion-Conclusions

We suggest that poor postural control as well as perception of verticality observed in preterm-born children could be due to immaturity of the cortical processes involved in the motor control and in the treatment of perception and orientation of verticality.

Long-term effects from bacterial meningitis in childhood and adolescence on postural control

Bacterial meningitis in childhood is associated with cognitive deficiencies, sensorimotor impairments and motor dysfunction later in life. However, the long-term effects on postural control is largely unknown, e.g., whether meningitis subjects as adults fully can utilize visual information and adaptation to enhance stability. Thirty-six subjects (20 women, mean age 19.3 years) treated in childhood or adolescence for bacterial meningitis, and 25 controls (13 women, mean age 25.1 years) performed posturography with eyes open and closed under unperturbed and perturbed standing. The meningitis subjects were screened for subjective vertigo symptoms using a questionnaire, clinically tested with headshake and head thrust test, as well as their hearing was evaluated. Meningitis subjects were significantly more unstable than controls during unperturbed (p≤0.014) and perturbed standing, though while perturbed only with eyes open in anteroposterior direction (p = 0.034) whereas in lateral direction both with eyes open and closed (p<0.001). Meningitis subjects had poorer adaption ability to balance perturbations especially with eyes open, and they frequently reported symptoms of unsteadiness (88% of the subjects) and dizziness (81%), which was found significantly correlated to objectively decreased stability. Out of the 36 subjects only 3 had unilateral hearing impairment. Hence, survivors of childhood bacterial meningitis may suffer long-term disorders affecting postural control, and would greatly benefit if these common late effects became generally known so treatments can be developed and applied.

Children's head movements and postural stability as a function of task

Manual dexterity and postural control develop throughout childhood, leading to changes in the synergistic relationships between head, hand and posture. But the postural developments that support complex manual task performance (i.e. beyond pointing and grasping) have not been examined in depth. We report two experiments in which we recorded head and posture data whilst participants simultaneously performed a visuomotor task. In Experiment 1, we explored the extent to which postural stability is affected by concurrently performing a visual and manual task whilst standing (a visual vs. manual-tracking task) in four age groups: 5-6 years (n = 8), 8-9 years (n = 10), 10-11 years (n = 7) and 19-21 years (n = 9). For visual tracking, the children's but not adult's postural movement increased relative to baseline with a larger effect for faster moving targets. In manual tracking, we found greater postural movement in children compared to adults. These data suggest predictive postural compensation mechanisms develop during childhood to improve stability whilst performing visuomotor tasks. Experiment 2 examined the extent to which posture is influenced by manual activity in three age groups of children [5-6 years (n = 14), 7-8 years (n = 25), and 9-10 years (n = 24)] when they were seated, given that many important tasks (e.g. handwriting) are learned and performed whilst seated. We found that postural stability varied in a principled manner as a function of task demands. Children exhibited increased stability when tracing a complex shape (which required less predictive postural adjustment) and decreased stability in an aiming task (which required movements that were more likely to perturb posture). These experiments shed light on the task-dependant relationships that exist between postural control mechanisms and the development of specific types of manual control.

Reliability of postural control measures in children and young adolescents

Although many studies have been carried out regarding postural stability during pediatric age, reliable information and a complete analysis of all age groups are still lacking. The purpose of this study was to verify the test-retest reliability of posturographic parameters in four sensory conditions and provide normative values for children and young adolescents. 289 subjects, aged 6-14 years, were assessed by means of the static posturography system SVeP. 173 elementary school pupils (114 males and 59 females, aged 6-10 years; mean age 8.80 ± 1.53) and 116 middle school students (60 males and 56 females, aged 11-14 years; mean age 12.6 ± 0.9) underwent static posturography in two consecutive trials with four testing conditions: eyes open and eyes closed with and without foam pads. The participants were divided into nine age groups. Thirty healthy young adults were also recruited for comparison. The analysis of test-retest reliability demonstrated an excellent reliability of velocity measurement and a moderate reliability of area measurement. Velocity and area decreased significantly with age in all sensory conditions, indicating an improvement in postural control from childhood to adolescence. Postural stability had not reached the adult level by the age of 13-14 years. Reliable information regarding postural stability can be obtained in children and young adolescents by means of stabilometric parameters. These data can be used as a reference for early detection of atypical postural development and for the assessment of dizziness and balance disorders in children.

Reliability and validity of the Trunk Impairment Scale in children and adolescents with cerebral palsy

Standardized clinical tools are useful for treatment planning and evaluation, however clinical tools to assess quality in trunk movements in children with cerebral palsy (CP) are sparse. We have recently reported good intra- and inter-observer reliability of the Trunk Impairment Scale (TIS) in 5-12 year old children with CP. The aim of this study was to assess reliability in adolescents (13-19 years old), and to assess the construct validity in children and adolescents in the whole age spectrum from 5 to 19 years. Video recordings of 17 children with CP with Gross Motor Function Classification (GMFCS) level I-IV were analyzed by three observers on two occasions. For construct validity the TIS was compared with Gross Motor Function Measure (GMFM), in 37 children with GMFCS levels I-IV. Intraclass correlation coefficients varied between 0.82 and 0.98, and 86% of the kappa values varied between 0.61 and 1.00, suggesting high inter- and intra-observer reliability. The smallest detectable difference (SDD) of the TIS (scale range 0-23) varied between 2.55 and 3.82 for intra- and 4.07-8.23 for inter-observer observations. The high inter-observer SDD was partly due to consistently lower TIS scores by one observer. The correlation between the TIS total score and the dimension scores of the GMFM was high (Spearman's rho: 0.80-0.87), while decreasing GMFCS levels were associated with increasing total TIS score; both findings indicating good construct validity of the TIS. This study suggests that the TIS is a reliable and valid measure of trunk control for both children and adolescents with cerebral palsy.

Balance function in patients with Williams syndrome

Impaired control of balance has been described in Williams syndrome (WS). The aim of this study was to investigate balance function by means of clinical and instrumental tests in order to measure postural sway in people with WS in an objective way. 23 WS patients (11 males, 12 females, mean age 17.52 ± 8.33 years) and 23 healthy subjects (11 males, 12 females, mean age 17.74 ± 8.93 years) performed static posturography with eyes open and closed, on a firm surface and on foam pads. The WS patients had higher mean length, velocity and surface values than controls under all of the test conditions, and their length and surface values were significantly higher in the eyes open test. The cognitive abilities of the WS patients were not related to their stabilometric performance. The greatest differences between the WS patients and the controls were found mainly in the older subjects. WS patients are more unstable than healthy subjects of the same age, particularly when they use visual information to maintain their balance: i.e. under conditions of normal everyday life. Possible explanations may be the ophthalmologic problems and the visuospatial difficulties attributed to a neural processing abnormality involving the dorsal stream impairment model. The balance function of WS patients is different from that of normal developing subjects, especially after adolescence when postural control is generally complete. This suggests an atypical developmental trajectory.

Balancing on a Slackline: 8-Year-Olds vs. Adults

Children are less stable than adults during static upright stance. We investigated whether the same holds true for a task that was novel for both children and adults and highly dynamic: single-legged stance on a slackline. We compared 8-year-olds with young adults and assessed the following outcome measures: time on the slackline, stability on the slackline (calculated from slackline reaction force), gaze movement, head-in-space rotation and translation, trunk-in-space rotation, and head-on-trunk rotation. Eight-year-olds fell off the slackline quicker and were generally less stable on the slackline than adults. Eight-year-olds also showed more head-in-space rotation and translation, and more gaze variability around a visual anchor point they were instructed to fixate. Trunk-in-space and head-on-trunk rotations did not differ between groups. The results imply that the lower postural stability of 8-year-olds compared to adults – as found in simple upright stance – holds true for dynamic, novel tasks in which adults lack the advantage of more practice. They also suggest that the lack of head and gaze stability constitutes an important limiting factor in children’s ability to master such tasks.

The effects of repetitive haemarthrosis on postural balance in children with haemophilia

Sensory information from visual, vestibular and proprioceptive systems is necessary to control posture and balance. Impairment in proprioception due to repetitive joints bleeding may lead to a deficit in postural balance which, in turn, leads to high joint stress and risk of bleeding recurrence. Despite the increase in attention in this field during the past few years, the data concerning to how bleeds can affect postural control in children with haemophilia (CWH) remain scarce. This study aimed to evaluate the postural balance in CWH. Twenty CWH Haemophilia Group (HG) and 20 age-matched children Control Group (CG) were recruited to this study. A force plate was used to record centre of pressure (COP) displacement under four different postural conditions during quiet standing: eyes open on firm surface, eyes open on foam surface, eyes closed on firm surface and eyes closed on a foam surface. Variables of COP as sway area and mean velocity and in anterior-posterior (y) medio-lateral (x) direction were processed and for each variable sensory, quotients were calculated and compared between groups. No differences were found in visual and vestibular quotients variables between groups. A higher value was found in sway area variable on proprioception quotient in the HG when compared with CG (P = 0.042). CWH with repetitive joint bleed on lower limbs showed differences in postural balance when compared with non-haemophiliac children. The identification of early balance impairments in CWH can help us understand better the effects of bleeds inside joints on postural control and plan a more effective preventive and rehabilitative treatment.

Independent walking as a major skill for the development of anticipatory postural control: evidence from adjustments to predictable perturbations

Although there is suggestive evidence that a link exists between independent walking and the ability to establish anticipatory strategy to stabilize posture, the extent to which this skill facilitates the development of anticipatory postural control remains largely unknown. Here, we examined the role of independent walking on the infants' ability to anticipate predictable external perturbations. Non-walking infants, walking infants and adults were sitting on a platform that produced continuous rotation in the frontal plane. Surface electromyography (EMG) of neck and lower back muscles and the positions of markers located on the platform, the upper body and the head were recorded. Results from cross-correlation analysis between rectified and filtered EMGs and platform movement indicated that although muscle activation already occurred before platform movement in non-walking infants, only walking infants demonstrated an adult-like ability for anticipation. Moreover, results from further cross-correlation analysis between segmental angular displacement and platform movement together with measures of balance control at the end-points of rotation of the platform evidenced two sorts of behaviour. The adults behaved as a non-rigid non-inverted pendulum, rather stabilizing head in space, while both the walking and non-walking infants followed the platform, behaving as a rigid inverted pendulum. These results suggest that the acquisition of independent walking plays a role in the development of anticipatory postural control, likely improving the internal model for the sensorimotor control of posture. However, despite such improvement, integrating the dynamics of an external object, here the platform, within the model to maintain balance still remains challenging in infants.

A small sample test of the factor structure of postural movement and bilateral motor integration using structural equation modeling

The goal of this study was to examine the relationship between the validity of postural movement and bilateral motor integration in terms of sensory integration theory. Participants in this study were 61 Chinese children ages 48 to 70 months. Structural equation modeling was applied to assess the relation between measures tapping postural movement and bilateral motor integration: for postural movement, the measures involve the Monkey Task, Side-Sit Co-contraction, Prone on Elbows, Wheelbarrow Walk, Airplane, and Scooter Board Co-contraction from the DeGangi-Berk Test of Sensory Integration, and Standing Balance with Eyes Closed/Opened in Southern California Sensory Integration Tests. For bilateral motor integration, the measures chosen were the Rolling Pin Activity, Jump and Turn, Diadokokinesis, Drumming, and Upper Extremity Control from the DeGangi-Berk Test of Sensory Integration, and Cross the Midline in Southern California Sensory Integration Tests (SCSIT). Postural movement was highly correlated with the bilateral motor integration. The factor structure fit the theoretical conceptualization, classifying postural movement and bilateral motor integration together in the same category. Therapists could combine two separate objectives (postural movement and bilateral motor integration) of intervention in an activity to improve the adaptive skills based on the vestibular-proprioceptive integration.

Spherical lenses and prisms lead to postural instability in both dyslexic and non dyslexic adolescents

There is controversy as to whether dyslexic children present systematic postural deficiency. Clinicians use a combination of ophthalmic prisms and proprioceptive soles to improve postural performances. This study examines the effects of convergent prisms and spherical lenses on posture. Fourteen dyslexics (13-17 years-old) and 11 non dyslexics (13-16 years-old) participated in the study. Quiet stance posturography was performed with the TechnoConcept device while subjects fixated a target at eye-level from a distance of 1_m. Four conditions were run: normal viewing; viewing the target with spherical lenses of -1 diopter (ACCOM1) over each eye; viewing with -3 diopters over each eye (ACCOM3); viewing with a convergent prism of 8 diopters per eye. Relative to normal viewing, the -1 lenses increased the surface of body sway significantly whereas the -3 diopter lenses only resulted in a significant increase of antero-posterior body sway. Thus, adolescents would appear to cope more effectively with stronger conflicts rather than subtle ones. The prism condition resulted in a significant increase in both the surface and the antero-posterior body sway. Importantly, all of these effects were similar for the two groups. Wavelet analysis (time frequency domain) revealed high spectral power of antero-posterior sway for the prism condition in both groups. In the ACCOM3 condition, the spectral power of antero-posterior sway decreased for non dyslexics but increased for dyslexics suggesting that dyslexics encounter more difficulty with accommodation. The cancelling time for medium range frequency (believed to be controlled by the cerebellum), was shorter in dyslexics, suggesting fewer instances of optimal control. We conclude that dyslexics achieve similar postural performances albeit less efficiently. Prisms and lenses destabilize posture for all teenagers. Thus, contrary to adults, adolescents do not seem to use efferent, proprioceptive ocular motor signals to improve their posture, at least not immediately when confronted to convergence accommodation conflict.

Do adolescent idiopathic scoliosis (AIS) neglect proprioceptive information in sensory integration of postural control?

Introduction

It has been reported that AIS rely much more on ankle proprioception to control the amplitude of the balance control commands as compared to age-matched healthy adolescents. Our hypothesis was that AIS do not neglect proprioceptive information to control posture probably because of their vestibular deficits. We investigated the proprioceptive contribution to postural control in AIS which expresses spinal deformity during a crucial transitional period of ontogenesis.

Methods

10 adolescents with idiopathic scoliosis (AIS) with moderate spinal deformity (10° < Cobb Angle >35°) and 10 control adolescents (CA) had to maintain vertical stance while very slow oscillations in the frontal plane (below the detection threshold of the semicircular canal system) were applied to the support with the eyes open and closed. Postural orientation and segmental stabilisation were analysed at head, shoulder, trunk and pelvis levels.

Results

Scoliosis did not affect vertical orientation control and segmental stabilization strategies. Vision improves postural control in both CA and AIS, which seem more dependent on visual cues than adults.

Conclusions

AIS as CA were unable to control efficiently their postural orientation on the basis of the proprioceptive cues, the only sensory information available in the EC situation, whereas in the same condition healthy young adults present no difficulty to achieve the postural control. This suggests that AIS as CA transitory neglect proprioceptive information to control their posture. These results and previous studies suggest the existence of different afferent pathways for proprioceptive information subserving different parts in sensory integration of postural control. We conclude that the static proprioceptive system is not affected by the idiopathic scoliosis, while the dynamic proprioceptive system would be mainly affected.