Does adolescent idiopathic scoliosis relate to vestibular disorders? A systematic review

Incidence and Importance of Peripheral Vestibular Dysfunction in Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is a common form of scoliosis. As the name suggests, etiopathogenesis is not clearly defined, so treatment is still anchored in the musculoskeletal theory and correction/prevention of high Cobb angle values. This study aimed to determine whether there is any connection between developing scoliotic curvature and a positive history of motion sickness as a symptom of a peripheral vestibular dysfunction/deficit, and if vestibular rehabilitation exercises could be integrated into the treatment plan. The study was conducted over 12 months on a selected population of 159 patients to evaluate or treat scoliotic curvatures in a private clinic. The collected data were analyzed using IBM SPSS Statistics 25 and illustrated using Microsoft Office Excel/Word 2021. Patients with peripheral vestibular dysfunction had significantly higher Cobb angle values when compared to patients with a negative result in an instrumental test for peripheral vestibular dysfunction. Motion sickness was considerably more associated with peripheral vestibular dysfunction, and a positive Fukuda stepping test was associated with a positive history of motion sickness. Adolescent idiopathic scoliosis with higher Cobb angles is related to positive motion sickness history as part of peripheral vestibular dysfunction. Conservative treatment for scoliosis could incorporate sensory integration techniques, and a positive history of motion sickness could be an indicator of a higher risk of progression in adolescent idiopathic scoliosis.

Deficits of Sensory Integration and Balance as Well as Scoliotic Changes in Young Schoolgirls

The aim of this study was to assess the relationship between sensory integration and balance deficits as well as scoliotic changes in young schoolgirls. The study comprised 54 girls aged 11 years with scoliotic changes. The Clinical Test of Sensory Integration and Balance of the Biodex Balance System platform were used to analyze the deficits in sensory integration and balance. Scoliotic changes were assessed using the Diers Formetric III 4D optoelectronic method. In the present study, there was a significant relationship between sensory integration and balance deficits as well as spine curvature angle (°) (p = 0.01), vertebral surface rotation (°) (p = 0.03), pelvic tilt (°) (p = 0.02), and lateral deviation (mm) (p = 0.04). The integration of the sensory systems has a positive effect on the structure of the intended and controlled movement as well as body posture and the development of the spine. In the treatment of scoliotic changes, one should also consider exercises that improve sensory integration as well as position and balance reactions.

Postural control through force plate measurements in female AIS patients compared to their able-bodied peers

The present understanding of the mechanisms responsible for postural deficit in adolescent idiopathic scoliosis (AIS) is still insufficient. This is important because some authors see one of the causes of this disease in the impaired postural control. Moreover, there is a reciprocal link between the level of postural imbalance and the clinical picture of these people. Therefore, we compared the center-of-pressure (COP) indices of 24 patients with AIS to 48 controls (CON) during four 20-s quiet stance trials with eyes open (EO) or closed (EC) and on firm or foam surface. This included sway amplitude, speed, sample entropy and fractal dimension. AIS had poorer postural steadiness only in the most difficult trial. In the remaining trials, AIS did as well as CON, while presenting a greater COP entropy than CON. Thus, the factor that made both groups perform equally could be the increased sway irregularity in AIS, which is often linked to higher automaticity and lower attention involvement in balance control. After changing the surface from hard to foam, puzzling changes in sway fractality were revealed. The patients decreased the fractal dimension in the sagittal plane identically to the CON in the frontal plane. This may suggest some problems with the perception of body axes in patients and reveals a hitherto unknown cause of their balance deficit.

A perception bias of the gravitational vertical is confirmed in Adolescent Idiopathic Scoliosis

PURPOSE

Adolescent Idiopathic Scoliosis (AIS) is the most frequent spine deformity in adolescence. The cause of AIS remains unknown. Several studies show that AIS can be associated with a perception bias of gravitational vertical. In particularly, AIS patients with a right thoracic convexity exhibit deviation of the Subjective Postural Vertical. The origin of this disturbance could be located in trunk proprioceptive graciveptors. We wanted to verify this result with a population of lumbar and thoracolumbar AIS with left convexity.

METHODS

It was a multicenter, cross-sectional case-control study. Thirty adolescents with left lumbar or thoraco-lumbar AIS (age 14.3 ± 1.7 years; Cobb angle 27.6° ± 6.1°) and 30 controls matched for age (14.0 ± 1.5 years), were compared for Subjective Visual Vertical (SVV) measured in static and dynamic (optokinetic stimulation) conditions, and Subjective Postural Vertical (SPV).

RESULTS

For SVV, there was no difference in the two groups, for static and dynamic conditions. The SPV was significantly different between the two groups (p < 0.0001). The SPV was shifted to the left for most of the AIS patients (med - 2.4°[- 3.6; - 1.7]) compared with controls (med 0°[- 0.5; 1.7]). Adolescents with AIS perceived verticality with significant greater uncertainty in postural modality than controls (p = 0.017).

CONCLUSION

Our study confirms a significant directional bias in the orientation of SPV in left lumbar or thoraco-lumbar AIS. This confirmation paves the way to a new physiopathological model focused on trunk proprioception.

LEVEL OF EVIDENCE

III.

Is self-image, in reference to the gravitational vertical, altered in adolescent idiopathic scoliosis? A multicenter, single-blind, case-control study

PURPOSE

Adolescent idiopathic scoliosis (AIS) is associated with perturbation of orthostatic postural control. In humans, orthostatic postural control is organized around the gravitational vertical (GV). Perception of the GV involves a bottom-up process (central integration of multisensorial information) and a top-down process that uses cognitive mechanisms relying on body image. This study hypothesized that AIS would be associated with an erroneous central representation of verticality. The objective was to demonstrate an altered top-down process of sense of verticality in AIS.

METHODS

This multicenter, single-blind, case-control study evaluated 63 adolescent girls with AIS divided into two groups (major AIS (n = 31) and minor AIS (n = 32)) and 30 matched non-scoliotic adolescents. Participants scored their perception of trunk appearance in an upright position using a pictographic scale. The outcome measure was the difference between perception score and real trunk deformity.

RESULTS

Participants with major AIS presented with misperception of their trunk appearance in an upright position when compared with those with minor AIS or controls.

CONCLUSION

Adolescents with major AIS underestimate their trunk deformity in an upright position. This suggests an altered representation of body image, affecting top-down control of sense of verticality.

Evaluation attempt of own body sensing amongst persons with and without scoliosis

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a common structural spine deformity affecting 2%-4% of adolescents. Due to the unknown cause of idiopathic scoliosis, its therapy is a long-term and often unsatisfactory process. In the literature, it is often suggested that problems related to the feeling of one's own body are caused by AIS.

OBJECTIVE

The aim of this study was to assess the feeling of one's own body among children with and without scoliosis on the example of feeling the head position, pelvis shape and balance.

METHOD

The research included 62 children: 30 with scoliosis and 25 without diagnosed scoliosis with an age range between 11 to 19 years. The minimum scoliosis value was 7∘ and the maximum was 53∘. The average value was 25∘. During the study, three functional tests were used: Cervical Joint Position Error Test (CJPET), Clinical Test of Sensory Integration on Balance (CTSIB) and Body proportion demonstration test (BPDT).

RESULTS

The results of the tests showed statistically significant differences (CJPET p= 3.54*10-14, CTSIB p= 0.0376, BPDT p= 0.0127). However, none of the studies showed a correlation between the results of people with scoliosis and the value of their Cobb angles.

The orthopedic characterization of cfap298tm304 mutants validate zebrafish to faithfully model human AIS

Cerebrospinal fluid (CSF) circulation relies on the beating of motile cilia projecting in the lumen of the brain and spinal cord cavities Mutations in genes involved in cilia motility disturb cerebrospinal fluid circulation and result in scoliosis-like deformities of the spine in juvenile zebrafish. However, these defects in spine alignment have not been validated with clinical criteria used to diagnose adolescent idiopathic scoliosis (AIS). The aim of this study was to describe, using orthopaedic criteria the spinal deformities of a zebrafish mutant model of AIS targeting a gene involved in cilia polarity and motility, cfap298tm304. The zebrafish mutant line cfap298tm304, exhibiting alteration of CSF flow due to defective cilia motility, was raised to the juvenile stage. The analysis of mutant animals was based on micro-computed tomography (micro-CT), which was conducted in a QUANTUM FX CALIPER, with a 59 µm-30 mm protocol. 63% of the cfap298tm304 zebrafish analyzed presented a three-dimensional deformity of the spine, that was evolutive during the juvenile phase, more frequent in females, with a right convexity, a rotational component and involving at least one dislocation. We confirm here that cfap298tm304 scoliotic individuals display a typical AIS phenotype, with orthopedic criteria mirroring patient's diagnosis.

Research progress on the etiology and pathogenesis of adolescent idiopathic scoliosis

Etiology of adolescent idiopathic scoliosis (AIS), a complicated three-dimensional spinal deformity with early-onset, receives continuous attention but remains unclear. To gain an insight into AIS pathogenesis, this review searched PubMed database up to June 2019, using key words or medical subject headings terms including "adolescent idiopathic scoliosis," "scoliosis," "pathogenesis," "etiology," "genetics," "mesenchymal stem cells," and their combinations, summarized existing literatures and categorized the theories or hypothesis into nine aspects. These aspects include bone marrow mesenchymal stem cell studies, genetic studies, tissue analysis, spine biomechanics measurements, neurologic analysis, hormone studies, biochemical analysis, environmental factor analysis, and lifestyle explorations. These categories could be a guidance for further etiology or treatment researches to gain inspiration.

Impact of the Vestibular System on the Formation and Progression to Idiopathic Scoliosis: A Review of Literature

The physiopathogenesis of adolescent idiopathic scoliosis remains unknown. However, a multifactorial pathogenesis is being assumed. Besides biomechanical, biochemical, and genetic factors, some studies have focused on congenital or acquired abnormalities in the vestibular organ with consecutive development of scoliosis. This study aims to analyze a possible correlation between any vestibular organ congenital or acquired pathologies and scoliosis based on the current literature. Therefore, we conducted a literature search in three databases, with search terms such as “scoliosis,” “organ of balance,” “idiopathic scoliosis,” “vestibular organ,” “spine,” and “balance.” Fifteen studies were selected and used for research. The relationship between scoliosis and vestibular organ abnormalities was recorded from all included works. Seven studies demonstrated a direct correlation between vestibular organ anatomical abnormalities and the form of the scoliotic spine. Another study confirmed the influence of the pathology of the vestibular organ on scoliosis but questioned whether it had an impact on the formation or the progression of the curvature. Others demonstrated a temporal overlap of the embryonic development of the vestibular organ and the beginning of pre-scoliotic characteristics, but their relationship remained questionable. In three studies, the correlation remained unclear, and any context has been denied. It seems unlikely that an isolated vestibular disorder can trigger structural scoliosis. However, the vestibular system pathologies may certainly occur in the multifactorial genesis of idiopathic scoliosis. Whether the correlation refers to the expression or the progression of scoliosis or may even have an influence on both remains unclear. New treatment options could be derived from these findings with a positive influence on the course of the deformity.

Lateral semi-circular canal asymmetry in females with idiopathic scoliosis

Purpose

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal structural deformity that occurs in otherwise normal individuals. Although curve progression and severity vary amongst individuals, AIS can lead to significant cosmetic and functional deformity. AIS etiology has been determined to be genetic, however, exact genetic and biological processes underlying this disorder remain unknown. Vestibular structure and function have potentially been related to the etiopathogenesis of AIS. Here, we aimed to characterize the anatomy of the semicircular canals (SCC) within the vestibular system through a novel approach utilizing T2-weighted magnetic resonance images (MRI).

Methods

Three dimensional, MRI-based models of the SCCs were generated from AIS subjects (n = 20) and healthy control subjects (n = 19). Linear mixed models were used to compare SCC morphological measurements in the two groups. We compared side-to-side differences in the SCC measurements between groups (group*side interaction).

Results

Side-to-side differences in the lateral SCC were different between the two groups [false discovery rate adjusted p-value: 0.0107]. Orientation of right versus left lateral SCC was significantly different in the AIS group compared to the control group [mean side-to-side difference: -4.1°, 95% CI: -6.4° to -1.7°]. Overall, among subjects in the AIS group, the left lateral SCC tended to be oriented in a more horizontal position than subjects in the control group.

Significance

Asymmetry within the SCCs of the vestibular system of individuals with AIS potentially results in abnormal efferent activity to postural muscles. Consequences of this muscular activity during periods of rapid growth, which often coincides with AIS onset and progression, warrant consideration.

PIEZO2: A Novel Molecule Involved in the Development of AIS

STUDY DESIGN

A case-control study.

OBJECTIVE

This study aimed to investigate the potential role of PIEZO2 gene in the development of AIS.

SUMMARY OF BACKGROUND DATA

Mutations of PIEZO2 gene have been reported to be associated with progressive scoliosis and impaired proprioception. Previous studies showed that patients with AIS may have impaired proprioception. However, there is lack of knowledge concerning the mechanism underlying the proprioception of AIS patients and the role of PIEZO2 gene in the etiology of AIS.

METHODS

Proprioception tests were performed in both AIS patients and age-matched healthy controls. Based on the falling risk scores, AIS patients were divided into impaired proprioception group and unimpaired proprioception group. Paraspinal muscle was collected from 34 AIS patients during surgery. The tissue expression of PIEZO2 was compared between the impaired group and the unimpaired group. In addition, the average number of muscle fibers in the muscle spindle was compared between the two groups.

RESULTS

Proprioception test showed that patients had significantly higher falling index (41.7 ± 16.5 vs. 11.3 ± 8.3, P = 0.004). In addition, the expression of PIEZO2 gene was remarkably decreased in the impaired group (0.51 ± 0.24 vs. 1.00 ± 0.33, P = 0.04). The average number of muscle fibers in the muscle spindle was significantly decreased in AIS patients of the impaired group than those of the unimpaired group (2.2 ± 1.3 vs. 3.5 ± 2.1, P = 0.04). PIEZO2 expression level was remarkably correlated with the average number of muscle fibers in the muscle spindle (r = 0.352, P = 0.04).

CONCLUSION

Proprioception is remarkably impaired in patients with AIS. Abnormal expression of PIEZO2 may play a role in AIS via altered proprioception and number of muscle fibers in the muscle spindles. Further investigation is warranted to illustrate the mechanism regulating PIEZO2 expression in AIS.

LEVEL OF EVIDENCE

4.

Case Report: Conservative Treatment of Adolescent Idiopathic Scoliosis Can Alter the Perception of Verticality. A Preliminary Study

Adolescent idiopathic scoliosis (AIS) is a lateral curvature of the spine of at least 10° Cobb's angle of unknown etiology. Some studies have found that patients with AIS have a Visual Verticality (VV) perception similar to healthy controls. This study aimed to analyze VV perception and postural balance differences in patients with AIS depending on the management, either based on observation or conservative treatment. Eighteen patients with AIS were included in this study. Nine patients were managed based on observation. The other nine underwent conservative treatment, such as bracing or exercise. Subjective Visual Vertical (SVV) and posturographic parameters were measured and analyzed. In the SVV test, patients who underwent treatment showed poor constant error in absolute values and mean absolute error, with statistically significant differences (p < 0.05). Only the Romberg Quotient for sway area was within the limits of statistical significance for posturographic parameters, with a lower value for patients under observation. This study found worse perception of verticality in patients receiving some type of conservative treatment than patients receiving only observation; whereas posturography showed similar values in both observation and treatment groups. Our results can be interpreted as the effect of treatment on the previous verticality perception adapted to the curvature.

Asymmetric Unilateral Vestibular Perception in Adolescents With Idiopathic Scoliosis

The cause of Adolescent Idiopathic Scoliosis (AIS) remains unclear, but one proposed cause of AIS is asymmetric vestibular function and the related descending drive to the spine musculature. The objective of this study was to determine if asymmetric vestibular function is present in individuals with AIS. Ten individuals with AIS (8F, 2M) and 10 healthy age- and sex-matched controls were exposed to 10s-long virtual rotations induced by monaural or binaural electrical vestibular stimulation (EVS), and 10s-long real rotations delivered by a rotating chair. Using a forced-choice paradigm, participants indicated their perceived rotation direction (right or left) to stimuli of varying intensity. A Bayesian adaptive algorithm adjusted the stimulus intensity and direction to identify a stimulus level, which we called the direction recognition threshold, at which participants correctly identified the rotation direction 69% of the time. For unilateral vestibular stimuli (monaural EVS), the direction recognition thresholds were more asymmetric in all participants with AIS compared to control participants [(0.22-1.00 mA) vs. (0.01-0.21 mA); p < 0.001]. For bilateral vestibular stimuli, however, the direction recognition thresholds did not differ between groups for either the real or virtual rotations (multiple p > 0.05). Previous reports of semicircular canal orientation asymmetry in individuals with AIS could not explain the magnitude of the vestibular function asymmetry we observed, suggesting a functional cause to the observed vestibular asymmetry. Thus, the present results suggest that a unilateral vestibular dysfunction is linked to AIS, potentially revealing a new path for the screening and monitoring of scoliosis in adolescents.

Postural control in girls with adolescent idiopathic scoliosis while wearing a Chêneau brace or performing active self-correction: a pilot study

Background

It is known that adolescent idiopathic scoliosis (AIS) is often accompanied by balance deficits. This reciprocal relationship must be taken into account when prescribing new therapeutic modalities because these may differently affect postural control, interacting with therapy and influencing its results.

Objective

The purpose was to compare postural control in girls with AIS while wearing the Chêneau brace (BRA) or performing active self-correction (ASC) with their postural control in a quiet comfortable stance.

Methods

Nine subjects were evaluated on a force plate in three series of two 20-s quiet standing trials with eyes open or closed; three blocks were randomly arranged: normal quiet stance (QST), quiet stance with BRA, and quiet stance with ASC. On the basis of centre-of-pressure (COP) recordings, the spatial and temporal COP parameters were computed.

Results and Discussion

Performing ASC was associated with a significant backward excursion of the COP mean position with eyes open and closed (ES = 0.56 and 0.65, respectively; p < 0.05). This excursion was accompanied by an increase in the COP fractal dimension (ES = 1.05 and 0.98; p < 0.05) and frequency (ES = 0.78; p = 0.10 and ES = 1.14; p < 0.05) in the mediolateral (ML) plane. Finally, both therapeutic modalities decreased COP sample entropy with eyes closed in the anteroposterior (AP) plane. Wearing BRA resulted in ES = 1.45 (p < 0.05) while performing ASC in ES = 0.76 (p = 0.13).

Conclusion

The observed changes in the fractal dimension (complexity) and frequency caused by ASC account for better adaptability of patients to environmental demands and for their adequate resources of available postural strategies in the ML plane. These changes in sway structure were accompanied by a significant (around 25 mm) backward excursion of the mean COP position. However, this improvement was achieved at the cost of lower automaticity, i.e. higher attentional involvement in postural control in the AP plane. Wearing BRA may have an undesirable effect on some aspects of body balance.

Does postural stability differ between adolescents with idiopathic scoliosis and typically developed? A systematic literature review and meta-analysis

BACKGROUND

Postural stability deficits have been proposed to influence the onset and progression of adolescent idiopathic scoliosis (AIS). This study aimed to systematically identify, critically evaluate and meta-analyse studies assessing postural stability during unperturbed stance with posturography in AIS compared to typically developed adolescents.

METHODS

Studies from four electronic databases (PubMed, Scopus, CINAHL, PEDro) were searched and case-control methodological quality assessed using a risk-of-bias assessment tool and a posturography methodological quality checklist. Pooled data regarding centre of pressure (COP) parameters such as sway area, Mediolateral (ML) and Anteroposterior (AP) position and range were compared for AIS and typically developed adolescents using Cohen's d effect size (ES) and homogeneity estimates.

RESULTS

Eighteen studies for quality analysis and 9 of these for meta-analysis were identified from 971 records. Risk-of-bias assessment identified 6 high, 10 moderate and 2 low risk-of-bias studies. The posturography methodological quality checklist identified 4 low, 7 moderate and 7 high-quality studies. Meta-analysis was performed for sway area whereas ML and AP are presented in three different meta-analyses due to divergent measurement units used in the studies: ML position 1 (MLP1), ML position 2 (MLP2) and ML range (MLR); AP position 1 (APP1), AP position 2 (APP2) and AP range (APR). Cohen's d showed a medium ES difference in sway area 0.65, 95% CI (0.49-0.63), whereas ML showed no (MLP1, MLP2) and large (MLR) ES differences; MLP1 0.15, 95% CI (0.08-0.22); MLP2 0.14, 95% CI (0.08-0.19); and MLR 0.94, 95% CI (0.83-1.04). Cohen's d for AP showed small ES (APP1) and large ES difference (APP2 and APR); APP1 0.43, 95% CI (0.31-0.54); APP2 0.85, 95% CI (0.72-0.97); and APR 0.98, 95% CI (0.87-1.09). Cochran's Q and Higgins I2 showed homogeneity between studies.

CONCLUSIONS

There is moderate quality evidence for decreased postural stability in AIS measured as COP parameters sway area, ML and AP range with a positional shift posteriorly in the sagittal plane. The findings support studying postural stability in early stage AIS and also prospectively identify cause and effect of the curvature as well as effectiveness of postural control interventions in the prevention of scoliosis progression.

Considerations for Testing and Treating Children with Central Vestibular Impairments

This perspective explores common pediatric diagnoses that could present with central vestibular pathway dysfunction, leading to delays in motor development and postural control, and gaze instability. Specifically, the following diagnoses are considered: cerebral palsy, myelomeningocele, vestibular migraine, attention-deficit hyperactivity disorder, developmental coordination disorder, concussion, childhood cancer, congenital muscular torticollis, adolescent idiopathic scoliosis, and autism. Suggestions for clinical screening, vestibular function testing, and vestibular rehabilitation for children with these diagnoses are based on evidence for the efficacy of testing and interventions for children with peripheral vestibular hypofunction. More research is needed to explore peripheral and central vestibular function in children with these diagnoses. Testing and intervention methods may need to be modified to accommodate for the specific behavior and motor challenges that some children might present. Researchers should develop technology so that gaze stabilization exercises can be delivered in a fun, functional, and effective way.

Clinical balance tests, proprioceptive system and adolescent idiopathic scoliosis

PURPOSE

Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spinal column of unknown etiology. Multiple factors could be involved, including neurosensory pathways and, potentially, an elective disorder of dynamic proprioception. The purpose of this study was to determine whether routine balance tests could be used to demonstrate an elective alteration of dynamic proprioception in AIS.

METHODS

This was a multicentre case-control study based on prospectively collected clinical data, in three hospitals pediatric, with spine consultation, from January 2013 through April 2015. From an original population of 547 adolescents, inclusion and non-inclusion criteria indentified 114 adolescents with right thoracic AIS (mean age 14.5 ± 1.9 years, Cobb angle 35.7 ± 15.3°) and 81 matched adolescents without scoliosis (mean age 14.1 ± 1.9 years). Participants performed three routine clinical balance tests to assess the static and dynamic proprioception: the Fukuda-Utenberger stepping test (angle of rotation in degrees and distance of displacement in cm) to assess dynamic balance; the sharpened Romberg test and the unipedal stance test (eyes closed) to assess static balance.

RESULTS

There was no significant difference between AIS subjects and controls for the static tests, but there was a significant difference for the dynamic test for both measures: distance of displacement (p < 0.01) and angle of rotation (p < 0.0001). This result confirms our initial these: the dynamic proprioception is altered electively in AIS.

CONCLUSION

These findings confirm recent AIS studies. Our results might be related to immature central integration of dynamic proprioceptive input leading to a poorly adapted motor response, particularly for postural control of the, in AIS. These balance tests can be performed in routine practice. Their validity as a biomarker for screening and monitoring purposes should be assessed.

Sensorimotor Control Impairment in Young Adults With Idiopathic Scoliosis Compared With Healthy Controls

OBJECTIVE

It has been hypothesized that the impaired sensorimotor control observed in adolescents with idiopathic scoliosis (IS) may be related more to the onset of scoliosis than to the maturation of sensory systems or sensorimotor control mechanisms. The objective of this study was to assess sensorimotor control in adults diagnosed with IS in adolescence versus healthy controls.

METHODS

The study included 20 young adults 20 to 24 years of age (10 healthy controls and 10 diagnosed with adolescent IS but not treated for it). Binaural bipolar galvanic vestibular stimulation (GVS) was delivered to assess sensorimotor control. Vertical forces under each foot and upper body kinematics along the frontal plane were measured before GVS (2-second window), during GVS (2-second window), immediately after the cessation of GVS (1-second window), and during the following 2 seconds. Balance control was assessed by calculating the root mean square values of vertical forces and upper body kinematics.

RESULTS

Compared with healthy controls, the IS group showed greater body sway upon GVS; the amplitude of this sway was even greater immediately after the cessation of GVS-an outcome requiring sensorimotor control.

CONCLUSION

Compared with normal controls, adults who had been diagnosed with IS in adolescence showed altered balance control immediately following GVS. This finding suggests that dysfunctional sensorimotor control may be related to the onset of scoliosis rather than to a transient suboptimal development of the sensory systems or sensorimotor control mechanisms.

Cervicocephalic relocation test to evaluate cervical proprioception in adolescent idiopathic scoliosis

PURPOSE

Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine associated with disturbed postural control. Cervical proprioception participates in controlling orthostatic posture via its influence on head stabilization. We hypothesized that patients with AIS exhibit altered cervical proprioception.

METHODS

We conducted a case-control study to evaluate cervical proprioception using the cervicocephalic relocation test (CRT) in 30 adolescents with AIS (15.5 ± 1.5 years; Cobb 24.8° ± 9.5°) versus 14 non-scoliotic controls (14.6 ± 2.0 years). CRT evaluates cervical proprioception by measuring the capacity to relocate the head on the trunk after active rotation of the head in the transversal plane without visual control. Each subject performed ten right and then ten left head rotations.

RESULTS

The CRT results were pathological in 12 AIS patients (40 %). The CRT mean was significantly different between AIS patients with a pathological CRT (5° ± 1.4° for right rotation; 4.2° ± 0.9° for left rotation) compared with AIS patients with a normal CRT (2.7° ± 0.6° for right rotation; 2.9° ± 0.8° for left rotation) or with the control group (3.5° ± 2.1° for right rotation; 3.1° ± 1.2° for left rotation).

CONCLUSION

Cervical proprioception is impaired in certain AIS patients. This anomaly may worsen the prognosis of AIS (headache; balance disorders; worsened spinal deformity; complication after spinal fusion). We recommend systematic screening for altered cervical proprioception in AIS patients.

Evaluation of motion sickness susceptibility by motion sickness susceptibility questionnaire in adolescents with idiopathic scoliosis: a case-control study

PURPOSE

Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine, with unknown origin. Some studies have noted impaired postural balance in AIS, in particular, difficulty to manage situations with sensory conflict. The motion sickness susceptibility can be secondary to a sensory conflict, for example, between visual and vestibular information. Our hypothesis is: patients with AIS have difficulty in managing situations with sensory conflict and therefore have increased motion sickness susceptibility. The purpose of this study was to evaluate in AIS subjects by evaluating their susceptibility to motion sickness, as compared to a control group.

METHODS

We conducted an analysis of data on motion sickness susceptibility collected prospectively from 2012, with the B score of motion sickness susceptibility questionnaire. This evaluation was completed for 65 adolescents (age 14.5 ± 1.6 year) with major right thoracic AIS (Cobb = 40.7° ± 13.1°) and 71 matched controls (14.6 ± 1.6 year).

RESULTS

Adolescents with major right thoracic AIS were more susceptible to motion sickness (B score = 5.3 ± 5.8) than controls (B score = 3.4 ± 3.7) with significant difference (p = 0.025).

CONCLUSIONS

We interpret our results suggesting there is difficulty for patients with AIS to manage situations with sensory conflict. Previous studies focusing on situations with sensory conflict in AIS have required sophisticated technology. They are not accessible for routine patient management. Our research shows the same result with simple, non invasive, low-cost and quick method: B score of motion sickness susceptibility questionnaire.