How sacculo-collic function assessed by cervical vestibular evoked myogenic Potentials correlates with the quality of postural control in hearing impaired children?

OBJECTIVE: Functional integrity of vestibular end organs is essential for gaze stabilization, dynamic visual acuity, postural control and spatial orientation. Some authors hypothesized on the importance of saccules for postural control and motor development in children, including achievements such as standing up and walking. The purpose of this article was to observe how saccular dysfunction assessed by cervical Vestibular Evoked Myogenic Potentials (cVEMPs) correlates with the quality of postural control in non-syndromic deaf children. METHOD: Seventy-six non-syndromic hearing-impaired children were retrospectively included. Sacculo-collic pathway was assessed with cVEMPs elicited in bone conduction. The response was quoted "normal" if a reproducible wave P13-N23 of at least 50µV in amplitude was present, if not, it was quoted "absent". The sample was divided in 3 groups depending on the presence of the sacculo-collic responses: normal bilateral group (Group 1), normal unilateral (Group 2) and absent bilaterally group (Group 3). Motor assessment was achieved with Movement Assessment Battery for Children, second edition (MABC-2). Postural control (PC) was assessed using the dynamic Balance Quest platform. The scores obtained with MABC-2, and the postural parameters recorded on the Balance Quest platform (sway of Centre of Pressure and spectral power index) were analyzed and compared throughout the groups. RESULTS: Group 1 (normal bilateral) showed the best scores regarding motor abilities and postural stability within available normative data. Group 3 (absent bilateral) had the lowest motor and postural control skills. A good correlation between the scores obtained by MABC-2 motor test and dynamic posturography (Balance Quest) was observed. CONCLUSIONS: The presence of at least one sacculo-collic response would predict satisfactory static and dynamic motor and postural control skills in non-syndromic hearing-impaired children. MABC-2 and Dynamic Posturography Balance Quest appears reliable and comparable tools for PC assessment in hearing impaired children. In the light of these results, it appears that in young children candidates for uni- or bilateral CI whose walking is not yet acquired, should receive a vestibular assessment before surgery to avoid the risk of bilateral sacculo-collic function impairment.

Impact of Somatosensory Input Deficiency on Subjective Visual Vertical Perception in Children With Reading Disorders.

Purpose: Preliminary evidence indicated that children with a reading disorder (RD) may have deviance in their ability to perform high demanding cognitive tasks, such as reading, depending on somatosensory inputs. Until now, only anecdotical reports suggested that improving somatosensory inputs may influence their ability to maintain a stable perception of the visual world despite continuous movements of our eyes, head, and body. Here, we investigated whether changes in upright perception, the subjective visual vertical (SVV), were modulated by somatosensory inputs in a group of children with RD. Method: The SVV task was used under two distinct conditions, i.e., with or without somatosensory inputs from the foot. We enrolled a group of 20 children with reading disorders and 20 sex-, age-, IQ- matched children with neurotypical development. Results: Responses to the SVV task were found to be significantly less accurate in children with RD than in children with neurotypical development (p < 0.001). In the latter, SVV response did not depend on somatosensory inputs from the foot. In contrast, in children with RD somatosensory inputs, either improved or worsen their SVV depending on the tilt direction (p < 0.01). Conclusion: Our results suggested that SVV responses in children with RD could be related to an immaturity for heteromodal sensory integration, including somatosensory inputs.

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.

Interactions between eye movements and posture in children with neurodevelopmental disorders.

In everyday life, our activities frequently involve the simultaneous performance of two or more tasks. Sharing attention between two concurrent tasks may result in a decrease in performance specifically among children with neurodevelopmental disorders. The objective of the study was to determine whether the influence of postural conditions (sitting condition, single task; standing condition, dual task) on eye movement performances on three visual tasks with high attentional load (visually-guided saccade task, memory-guided saccade task and fixation task) was different in children with neurodevelopmental disorders (attention deficit and hyperactive disorder, dyslexia, and high functioning autism spectrum disorder) when compared to typically developing children. One hundred and four children (26 per group, sex-age- and IQ-matched groups) were evaluated. We found that for the fixation task only, the three groups of children with neurodevelopmental disorders had poorer eye movements performances in the standing condition compared to the sitting condition while no such difference was found for typically developing children. We suggest that children with neurodevelopmental disorders have fewer attentional resources available for performing correctly oculomotor tasks with high attentional load leading to impairment of these tasks for maintaining a good level of postural stability.

Vertical disconjugacy during reading in dyslexic and non-dyslexic children.

PURPOSE: The objective of this study was to explore vertical binocular coordination in dyslexic and non-dyslexic children during saccades and post-saccadic fixation period while reading a text. METHODS: Binocular eye movements were recorded by an infrared system (Mobile T2®, SuriCog) in thirty-six dyslexic children from 7.3 to 13.6 years of age (mean age: 10.4 ±â€¯0.3 years) who were asked to silently read a four-line text during binocular viewing. Data were compared to those of thirty-six age-matched non-dyslexic children. RESULTS: Vertical disconjugacy during post-saccadic fixation was higher in dyslexic children with respect to non-dyslexic children group. Vertical disconjugacy was not age-dependent either for dyslexic children or for non-dyslexic children. CONCLUSIONS: The poor binocular vertical coordination observed in dyslexic children while reading could suggest a deficiency in the cerebellum and/or extra-ocular muscles involved in vertical eye alignment. Moreover, the fact that this vertical binocular coordination was not age-dependent could be due to an abnormal eye position and/or to a dysfunction of midbrain structures involved in vertical vergences.

Postural Control and Emotion in Children with Autism Spectrum Disorders.

Autism Spectrum Disorders subjects (ASD) are well known to have deficits in social interaction. We recorded simultaneously eye movements and postural sway during exploration of emotional faces in children with ASD and typically developing children (TD). We analyzed several postural and ocular parameters. The results showed that all postural parameters were significantly greater in children with ASD; ASD made significantly fewer saccades and had shorter fixation time than TD, particularly in the eyes, and especially for unpleasant emotions. These results suggest that poor postural control of ASD and their impaired visual strategies could be due to a lack of interest in social cognition, causing a delay in the development of the cortical areas, and thus could have an effect on their postural control.

Postural Control in Children with Dyslexia: Effects of Emotional Stimuli in a Dual-Task Environment.

The aim of this study was to compare the visual exploration strategies used during a postural control task across participants with and without dyslexia. We simultaneously recorded eye movements and postural control while children were viewing different types of emotional faces. Twenty-two children with dyslexia and twenty-two aged-matched children without dyslexia participated in the study. We analysed the surface area, the length and the mean velocity of the centre of pressure for balance in parallel with visual saccadic latency, the number of saccades and the time spent in regions of interest. Our results showed that postural stability in children with dyslexia was weaker and the surface area of their centre of pressure increased significantly when they viewed an unpleasant face. Moreover, children with dyslexia had different strategies to those used by children without dyslexia during visual exploration, and in particular when they viewed unpleasant emotional faces. We suggest that lower performance in emotional face processing in children with dyslexia could be due to a difference in their visual strategies, linked to their identification of unpleasant emotional faces. Copyright © 2017 John Wiley & Sons, Ltd.

Discriminant validity of spatial and temporal postural index in children with neurodevelopmental disorders.

Autism, learning disabilities and attention deficit/hyperactive disorder are often comorbid disorders. In order to try and find some markers that might be transnosographic, we hypothesized that abnormal postural sway profiles may discriminate children with neurodevelopmental disorders (NDDs) from typically developing children. The aim of our study was thus to compare spatial and temporal measures of the Center of Pressure in three distinct groups of children with NDDs (high functioning autism spectrum disorders, learning disabilities (dyslexia) and attention deficit/hyperactive disorders) and in typically developing children. Postural performances were thus evaluated in 92 children (23 per group, sex-, age- and IQ-matched groups) by using the Multitest Equilibre platform (Framiral®). Two viewing conditions (eyes open and eyes closed) were tested on a stable and unstable platform. Results reported similar poor postural instability for the three groups of children with NDDs with respect to the typically developing children, and this was observed for both spatial as well as temporal analysis of displacement of the center of pressure. Such postural instability observed in children with NDDs could be due to impairment in using sensorial inputs to eliminate body sway, probably due to poor cerebellar integration.

Influence of both cutaneous input from the foot soles and visual information on the control of postural stability in dyslexic children.

Dyslexic children show impaired in postural stability. The aim of our study was to test the influence of foot soles and visual information on the postural control of dyslexic children, compared to non-dyslexic children. Postural stability was evaluated with TechnoConcept® platform in twenty-four dyslexic children (mean age: 9.3±0.29years) and in twenty-four non-dyslexic children, gender- and age-matched, in two postural conditions (with and without foam: a 4-mm foam was put under their feet or not) and in two visual conditions (eyes open and eyes closed). We measured the surface area, the length and the mean velocity of the center of pressure (CoP). Moreover, we calculated the Romberg Quotient (RQ). Our results showed that the surface area, length and mean velocity of the CoP were significantly greater in the dyslexic children compared to the non-dyslexic children, particularly with foam and eyes closed. Furthermore, the RQ was significantly smaller in the dyslexic children and significantly greater without foam than with foam. All these findings suggest that dyslexic children are not able to compensate with other available inputs when sensorial inputs are less informative (with foam, or eyes closed), which results in poor postural stability. We suggest that the impairment of the cerebellar integration of all the sensorial inputs is responsible for the postural deficits observed in dyslexic children.

The Effect of Training on Postural Control in Dyslexic Children.

The aim of this study was to explore whether a short postural training period could affect postural stability in dyslexic children. Postural performances were evaluated using Multitest Equilibre from Framiral. Posture was recorded in three different viewing conditions (eyes open fixating a target, eyes closed and eyes open with perturbed vision) and in two different postural conditions (on stable and unstable support). Two groups of dyslexic children participated in the study, i.e. G1: 16 dyslexic participants (mean age 9.9 ± 0.3 years) who performed short postural training and G2: 16 dyslexic participants of similar ages (mean age 9.1 ± 0.3 years) who did not perform any short postural training. Findings showed that short postural training improved postural stability on unstable support surfaces with perturbed vision: indeed the surface, the mean velocity of CoP and the spectral power indices in both directions decreased significantly, and the cancelling time in the antero-posterior direction improved significantly. Such improvement could be due to brain plasticity, which allows better performance in sensory process and cerebellar integration.

The effect of face exploration on postural control in healthy children.

The objective was to explore how face exploration affects postural control in healthy children. The novelty here is that eye movements and posture were simultaneously recorded. Three groups of children participated in the study: 12 children of 7.8±0.5 years old, 13 children of 10.4±0.5 years old and 12 children of 15.7±0.9 years old. Eye movements were recorded by video-oculography and postural stability was recorded by a platform. Children were invited to explore five emotional faces (neutral, happy, sad fear and angry). Analysis of eye movements was done on saccadic latency, percentage of exploration time spent and number of saccades for each specific region of interest (ROI): eyes, nose and mouth. Analysis of posture was made on surface area, sway length and mean velocity of the center of pressures (CoP). Results showed that visual strategies, exploration and postural control develop during childhood and adolescence. Indeed, after nine years-old, children started to look the eyes ROI firstly, then the nose ROI and finally the mouth ROI. The number of saccades decreased with the age of children. The percentage of exploration time spent in eyes ROI was longer than the others ROIs and greater for unpleasant faces (sad, fear and angry) with respect to pleasant emotional face (happy). We found that in front of sad and happy faces the surface area of the CoP was significantly larger compared to other faces (neutral and angry). These results suggest that visual strategies and postural control change during children's development and can be influenced by the emotional face.

Spatial and temporal analysis of postural control in dyslexic children.

OBJECTIVE: The aim of this study is to examine postural control of dyslexic children using both spatial and temporal analysis. METHODS: Thirty dyslexic (mean age 9.7±0.3years) and thirty non-dyslexic age-matched children participated in the study. Postural stability was evaluated using Multitest Equilibre from Framiral®. Posture was recorded in the following conditions: eyes open fixating a target (EO) and eyes closed (EC) on stable (-S-) and unstable (-U-) platforms. RESULTS: The findings of this study showed poor postural stability in dyslexic children with respect to the non-dyslexic children group, as demonstrated by both spatial and temporal analysis. In both groups of children postural control depends on the condition, and improves when the eyes are open on a stable platform. Dyslexic children have spectral power indices that are higher than in non-dyslexic children and they showed a shorter cancelling time. CONCLUSION: Poor postural control in dyslexic children could be due to a deficit in using sensory information most likely caused by impairment in cerebellar activity. SIGNIFICANCE: The reliability of brain activation patterns, namely in using sensory input and cerebellar activity may explain the deficit in postural control in dyslexic children.

Spatial and temporal postural analysis: a developmental study in healthy children.

The aim of this study was to explore further the development of postural control in healthy children. The novelty of this study was to resort to both spatial and temporal analysis of the center of pressure (CoP). Forty-six healthy children from 4 to 16 years old (mean age: 9.1±3 years) and a group of 13 healthy adults (mean age: 25±3 years) participated to this study. Postural control was tested on both a stable and an unstable platform in three different visual conditions: eyes open fixating a target, under optocinetic stimulation, and eyes closed. Resul*ts showed a significant decrease of both surface area as well as mean velocity of the center of pressure (CoP) during childhood. With the children's increasing age, the spectral power indices decreased significantly and the canceling time increased significantly. Such improvement in postural control could be due to a better use of sensorial inputs and cerebellar integration during development, allowing subjects to achieve more efficient postural control.