Changes in the Sensory Weighting Strategies in Balance Control Throughout Maturation in Children

Child and Adolescent Manganese Biomarkers and Adolescent Postural Balance in Marietta CARES Cohort Participants

BACKGROUND

Manganese (Mn) plays a significant role in both human health and global industries. Epidemiological studies of exposed populations demonstrate a dose-dependent association between Mn and neuromotor effects ranging from subclinical effects to a clinically defined syndrome. However, little is known about the relationship between early life Mn biomarkers and adolescent postural balance.

OBJECTIVES

This study investigated the associations between childhood and adolescent Mn biomarkers and adolescent postural balance in participants from the longitudinal Marietta Communities Actively Researching Exposures Study (CARES) cohort.

METHODS

Participants were recruited into CARES when they were 7-9 y old, and reenrolled at 13-18 years of age. At both time points, participants provided samples of blood, hair, and toenails that were analyzed for blood Mn and lead (Pb), serum cotinine, hair Mn, and toenail Mn. In adolescence, participants completed a postural balance assessment. Greater sway indicates postural instability (harmful effect), whereas lesser sway indicates postural stability (beneficial effect). Multivariable linear regression models were conducted to investigate the associations between childhood and adolescent Mn biomarkers and adolescent postural balance adjusted for age, sex, height-weight ratio, parent/caregiver intelligence quotient, socioeconomic status, blood Pb, and serum cotinine.

RESULTS

CARES participants who completed the adolescent postural balance assessment (n = 123 ) were 98% White and 54% female and had a mean age of 16 y (range: 13-18 y). In both childhood and adolescence, higher Mn biomarker concentrations were significantly associated with greater adolescent sway measures. Supplemental analyses revealed sex-specific associations; higher childhood Mn biomarker concentrations were significantly associated with greater sway in females compared with males.

DISCUSSION

This study found childhood and adolescent Mn biomarkers were associated with subclinical neuromotor effects in adolescence. This study demonstrates postural balance as a sensitive measure to assess the association between Mn biomarkers and neuromotor function. https://doi.org/10.1289/EHP13381.

Multisensory and biomechanical influences on postural control in children

Children's ability to maintain balance requires effective integration of multisensory and biomechanical information. The current project examined the interaction between such sensory inputs, manipulating visual input (presence vs. absence), haptic (somatosensory) input (presence vs. absence of contact with a stable or unstable finger support surface), and biomechanical (sensorimotor) input (varying stance widths). Analyses of mean velocity of the center of pressure and the percentage stability gain highlighted the role of varying multisensory inputs in postural control. Developmentally, older children (6-11 years) showed a multisensory integration advantage compared with their younger counterparts (3-5.9 years), with the impact of varying sensory inputs more closely akin to that seen in adults. Subsequent analyses of the impact of anthropometric individual difference parameters (e.g., height, leg length, weight, areas of base of support) revealed a shifting pattern across development. For younger children, these parameters were positively related to postural stability across experimental conditions (i.e., increasing body size was related to increasing postural control). This pattern transitioned for older children, who showed a nonsignificant relation between body size and balance. Interestingly, because adults show a negative relation between anthropometric factors and stability (i.e., increasing body size is related to decreasing postural control), this shift for the older children can be seen as a developmental transition from child-like to adult-like balance control.

Postural stability in strabismus and amblyopia

BACKGROUND

Postural control is a complex skill based on the collaboration of dynamic sensory mechanisms, namely the visual, vestibular, and somatosensory systems.

METHODS

A literature survey regarding postural stability in strabismus and amblyopia was conducted using databases in order to collect data for a narrative review of published reports and available literature.

RESULTS

The results of the literature survey were analyzed to provide an overview of the current knowledge of postural stability in strabismus and amblyopia. The results revealed that although postural control depends on the fundamental integration of three essential components (the visual, vestibular, and somatosensory systems), the role of vision is critical in postural stability. Once normal binocular vision is undesirably disrupted in childhood by some reason, especially in strabismus and/or amblyopia, balance is also affected. Abnormal balance affects coordination in gross and fine motor controls in school-age children and results in weakened academic performance and delayed social progress. It also impacts a child's general health, self-esteem, and safety.

CONCLUSIONS

Binocular vision is imperative for the maturation and preservation of balance control in children, as balance performance is reduced in strabismus and/or amblyopia.

Lifespan changes in postural control

Lifespan development of postural control shows as an inverted U-shaped function with optimal performance in young adults and similar levels of underperformance in children and older adults. However, similarities in children and older adults might conceal differences in underlying control processes. We mapped out age-related differences in postural control using center-of-pressure trajectories of 299 participants ranging from 7 to 81 years old in three tasks: stable stance, compromised vision, and narrowed base of support. Summary statistics (path length, ellipse area) replicated the well-known U-shape function also showing that compromising vision and narrowing the base of support affected older adults more than children. Stabilogram diffusion analysis (SDA) allows to assess postural control performance in terms of diffusion at short (< 1 s) and longer timescales. SDA parameters showed the strongest short-term drift in older adults, especially under compromised vision or narrowed base of support conditions. However, older adults accommodated their poor short-term control by corrective adjustments as reflected in long-term diffusion under eyes closed conditions and initiating anti-persistent behavior earlier compared with children and young adults in tandem stance. We argue that these results highlight the adaptability of the postural control system and warrant a reinterpretation of previous postural control frameworks.

Sensory organization of balance control in children with vestibular migraine and recurrent vertigo of childhood

Background

Migraine plays an important role in some subgroups of children with recurrent vertigo. Moreover, the migraine component varies from definite to possibly absent as defined in this spectrum of three disorders—vestibular migraine of childhood (VMC), probable VMC (pVMC), and recurrent vertigo of childhood (RVC). However, studies on the sensory organization of balance control in these three disorders are rare.

Objective

To explore the balance control of children with RVC, VMC, and pVMC, when the three sensory systems are challenged.

Method

A retrospective analysis was performed on 125 children with VMC (18 female and 15 male; aged 11.64 ± 2.74), pVMC (10 female and eight male; aged 11.78 ± 2.51), and RVC (32 female and 42 male; aged 11.10 ± 2.60). All children in each subtype were divided into groups of children aged ≤ 12 years old and 13–17 years old. Vestibular examination screening and assessment for postural control using the six conditions of the sensory organization test (SOT) were performed. The three primary outcome measures were: equilibrium score (ES), strategy score (SS), and sensory analysis score of the SOT.

Results

Equilibrium score under six different conditions and composite score increased with age (all P-values &lt; 0.05). The somatosensory and visual scores also improved with growing (P-values &lt; 0.05). However, vestibular scores did not increase significantly with age as the other senses did (P &gt; 0.05). In the children ≤ 12 year-old group, children with VMC had a significantly higher visual preference score than those with pVMC and RVC (P &lt; 0.05). There was an effect of age on the horizontal HIT. Ocular vestibular evoked myogenic potential (oVEMP), cervical vestibular evoked myogenic potential (cVEMP), and unilateral weakness (UW) values showed no significant difference among three diseases.

Conclusion

Compared with patients at the age of 13–17 years old and with RVC and pVMC (both ≤ 12 years old), children with VMC had a higher degree of reliance on visual signals to maintain their balance and a poorer central integration of peripheral information before reaching 12 years of age. In addition, vision may predominate by weakening vestibular function based on visuo-vestibular interactions. It must be noted that peripheral vestibular examinations could not distinguish the three disease subtypes.

Balance control impairments in Fabry disease

Background

Fabry disease (FD) is a rare inherited lysosomal storage disorder caused by the deficiency of the enzyme alpha-galactosidase A. This deficiency leads to an accumulation of glycosphingolipids leading to progressive and multisystemic disease, including renal, cardiac, and neurological damages. FD may also have neuro-otological and visual impairments, which can generate postural control alterations, inner ear, and vision being involved in this function. This study aimed to evaluate the impact of FD on postural control.

Methods

In total, fourteen adult patients (8 men/6 women, mean age = 37.6 ± 11.4 years) and two children (mean age = 11 years) with FD and 19 healthy adults (12 men/7 women, mean age = 36.5 ± 16.9 years) and two healthy children (mean age = 10.5 years) took part in this study. Postural control was evaluated by a sensory organization test combining three visual situations (eyes open, eyes closed, and sway referenced visual surround motion) with two platform situations (stable platform and sway referenced platform motion), aiming to calculate a composite equilibrium score (CES), a high score being representative of good postural control. Somatosensory (R^SOM), visual (R^VIS), and vestibular (R^VEST) contributions to postural control were calculated, a low score reflecting a poor use of the indicated sensory input.

Results

The CES was lower in adult patients with FD compared with the healthy subjects (p < 0.001). R^VIS (p = 0.001) and R^VEST (p = 0.003) were lower in patients with FD compared with the control group, whereas no difference in R^SOM was observed.

Conclusion

Inner ear and visual pathologies associated with the central nervous system impairments are factors of postural control impairments. Physical activities, which can also be rehabilitative, by maintaining or increasing the weight of proprioception, may help diminish dependency on altered sensorial inputs.

Correlation of SVINT and Sensory Organization Test in Children with Hearing Loss

Objective: The skull vibration-induced-nystagmus test (SVINT) is a noninvasive and effective screening tool for the function of the otolith and canal structures in children. It can instantaneously assess vestibular asymmetry. This study aimed to analyze the SVINT results of healthy children vs. children with hearing loss (HL) and to correlate it with sensory organization test (SOT) results as a functional balance evaluation tool. Design: This case-controlled study compared the results of SVINT to the results of the SOT of the computerized dynamic posturography (CDP) in a control group of 120 healthy normal-hearing children (i.e., NH group) vs. hearing loss (HL) group of 60 children, including 30 children with hearing aids (HAs) and 30 children with a unilateral cochlear implant (CI). The SVINT results were compared to the caloric test (CaT) and video head impulse test (vHIT) and associated with SOT scores. Results: Thirty-one children in the HL group had normal SVINT and normal SOT results. A total of 21 children in the HL group had SVINT-negative and abnormal results in the SOT (possibly due to bilateral vestibular loss (BVL)). Eight children in the HL group had positive SVINT and abnormal SOT results. However, none of the children had only positive SVINT with normal SOT findings. Moreover, 52% of children had a normal result on both the SOT and CaT, whereas 27% had abnormal results on both tests (17% bilateral weakness and 10% unilateral), and 22% had the only result of the SOT suggesting a functional abnormality. Similarly, when associating the result to vHIT, 51% had normal results on both tests, and 25% had abnormal results (13% bilateral and 12% unilateral weakness). Conclusion: SVINT findings can be correlated with SOT findings in the case of the unilateral vestibular lesion (UVL), which adds a diagnostic value in these pediatric cases but may differ in the case of the bilateral vestibular lesion (BVL). However, SVINT findings need to be cautiously interpreted in light of other test findings such as the SOT, CaT, and vHIT.

Postural control in Chiari I malformation: protocol for a paediatric prospective, observational cohort - potential role of posturography for surgical indication

INTRODUCTION

Chiari I malformation (CM1) is an anatomical abnormality characterised by the cerebellar tonsils descending at least 5 mm below the foramen magnum. CM1 causes obstruction of cerebrospinal fluid (CSF) circulation as well as direct compression on the brainstem, thus causing typical consequences (syringomyelia), and typical clinical features (characteristic headaches and neurological impairment). Surgery is the only available treatment, indicated when symptomatology is present. However, sometimes patients have atypical complaints, which are often suggestive of otolaryngological (ears, nose and throat, ENT) involvement. This may be difficult for a neurosurgeon to explain. Our study aims to investigate the relationship between one of these atypical symptoms, for example, postural instability, in a paediatric population using a Computerised Dynamic Posturography (Equitest, NeuroCom, Clackamas, OR). To our knowledge, there are no previously published studies carried out on children with CM1, using dynamic posturography.

METHODS AND ANALYSIS

Forty-five children aged 6-18 years old presenting with radiologically confirmed CM1 and presenting ENT clinical complaints will be included in the study for a duration of 3 years. As primary endpoint, posturographic results will be described in the population study. Second, posturographic results will be compared between patients with and without indication for surgery. Finally, preoperative and postoperative posturographic results, as well as CSF circulation quality at foramen magnum level, syringomyelia, sleep apnoea syndrome, scoliosis and behaviour will be compared in the operated patient group.

ETHICS AND DISSEMINATION

This protocol received ethical approval from the Clinical Research Delegation of Nancy University Hospital, in accordance with the National Commission on Informatics and Liberties (Commission Nationale de l'Informatique et des Libertés) (protocol number 2019PI256-107). Our data treatment was in accordance with the Methodology of reference Methodology Reference-004 specification for data policy. The study findings will be disseminated via peer-reviewed publications and conference presentations, especially to the Neurosphynx's rare disease healthcare network.

TRIAL REGISTRATION NUMBER

NCT04679792; Pre-results.