Effect of Postural Control Demands on Early Visual Evoked Potentials during a Subjective Visual Vertical Perception Task in Adolescents with Idiopathic Scoliosis

Neurophysiological, balance and motion evidence in adolescent idiopathic scoliosis: A systematic review

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a spinal deformity that affects approximately 4% of the world's population. Several hypotheses regarding the etiology of AIS have been investigated. In the last decades, impaired visual-spatial perception, alterations in spatial body orientation and sensory integration deficits have been documented.

OBJECTIVE

We aimed to summarize the neurophysiological, balance, and motion evidence related to AIS published in the last fifteen years, between January 2008 and April 2023. Both observational and interventional studies were considered. Only studies using quantitative assessment methods, such as electroencephalography (EEG), electromyography (EMG), magnetic resonance imaging (MRI), somatosensory evoked potentials, force platform, or motion capture, were included.

METHODS

1250 eligible records identified from online database searching were filtered by duplicate removal, title and abstract screening, and qualitative analysis. 61 articles met the inclusion criteria (i.e., Cobb range 10°-35°, age range 10-18 years) and were summarized.

RESULTS

We found significant evidence of impaired standing balance in individuals with AIS who greatly rely on visual and proprioceptive information to stay upright. EMG studies frequently reported an increased activity on the convex side of the intrinsic spinae muscles. EEG data show increased delta and theta power, higher alpha peak frequencies, and significant suppression in the alpha and beta bands in subjects with AIS during standing tasks. MRI studies report changes in white matter structures, differences in the vestibular system, and abnormal cortical activations over motor-related areas in subjects with AIS. Bracing appears to be an effective treatment for AIS, leading to improvements in static balance and gait. Methodological issues prevent reliable conclusions about the effects of other treatment options.

CONCLUSIONS

This review underscores the importance of quantitative assessment methods to explore the etiology and pathophysiology of AIS. Further research is needed to measure the impact of physical therapy and orthotic treatments on the neurophysiological mechanisms of the disease.

Effect of the type of brace on head to pelvis sagittal alignment of adolescents with Scheuermann's kyphosis

The aim of this study was to determine the effects of the Milwaukee brace and thoracolumbosacral orthosis (TLSO) on head to pelvis sagittal alignment in adolescents with Scheuermann's kyphosis (SK). A total of 52 adolescents with SK who were under brace treatment were studied. They underwent biplanar radiography of the head to pelvis (EOS Imaging, Paris, France) before and 6 months after the beginning of bracing. We measured T1 slope, neck tilt (NT), cervical sagittal vertical axis (cSVA), thoracic inlet angle (TIA), C0-C2 lordosis, C2-C7 lordosis, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA) and T1 spinopelvic inclination (T1SPi). There were no significant differences in baseline values of TIA, PT, SS, PI, SVA, TK, cSVA, NT and T1 slope between the two groups (p > 0.05). There were significant differences between the baseline and final measurements of T1 slope, cSVA, TK, LL, T1SPi and TIA in both groups (p < 0.05). The results imply that brace treatment can significantly affect head to pelvis sagittal parameters of adolescents with SK. However, there are no significant differences in the values of head to pelvis sagittal parameters when comparing short-term effect of TLSO and the Milwaukee brace.

Influence of Rehabilitation Aid with Biofeedback on the Rehabilitation Process during Remote Home-Based Rehabilitation

Ensuring the regularity and correctness of rehabilitation exercises in the home environment is a prerequisite for successful treatment. This clinical study compares balance therapy in the home environment on a conventional balance mat and an instrumented wobble board, with biofeedback supported by a rehabilitation scheme realized as web-based software that controls the course of rehabilitation remotely. The study included 55 patients with knee injuries. The control group consisted of 25 patients (12 females and 13 males, mean age 39 ± 12 years) and the study group of 30 patients (19 females and 11 males, mean age 40 ± 12 years). Treatment effects were compared using the ICS Balance Platform measurement system. Measurements showed significant differences in the change in ICS Balance platform parameters representing the dynamic stability of the patients. The dynamic stability improved more with the instrumented wobble board. The study did not show an influence of different methods of communication with patients during home-based rehabilitation.

Comparative Effects of Neuromuscular- and Strength-Training Protocols on Pathomechanical, Sensory-Perceptual, and Motor-Behavioral Impairments in Patients with Chronic Ankle Instability: Randomized Controlled Trial

(1) Background: Chronic ankle instability (CAI) is a complex condition that includes limited mobility, perceived instability, and recurrent ankle sprains are common characteristics that reduce the quality of life in subjects who suffer from CAI. Neuromuscular training and strength training have been recommended in CAI management interventions. However, there are contradictory findings on results when comparing neuromuscular training, strength training, and the control group. The objective of this study was to compare the effectiveness of 8 weeks of neuromuscular intervention training, strength training, and no intervention in a sporting population with reported CAI. (2) Methods: Sixty-seven athletes with CAI were randomly assigned to a neuromuscular training group (NG), strength training group (SG), or control group (CG). Participants completed 8 weeks of neuromuscular training (a combination of static and dynamic exercises), strength training (resistance band exercises), or no training. Outcome measures were assessed at baseline and after 8 weeks and included selfs-reported instability feeling (CAIT), dynamic balance (SEBT), ankle dorsiflexion range of motion (WBLT), and functional status (FAAM and FAAM-SPORT). (3) Results: There were significant differences between strength and control groups in the posteromedial direction of SEBT, FAAM, and FAAM-SPORT after 8 weeks of intervention. (4) Conclusions: Neuromuscular training and strength training based on resistance bands exercises showed significant improvements in ankle dorsiflexion, subjective feeling of instability, functional status, and dynamic balance in patients with CAI.

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.

Short-Term Effects of Balance Training with Stroboscopic Vision for Patients with Chronic Ankle Instability: A Single-Blinded Randomized Controlled Trial

Chronic Ankle Instability (CAI) is one of the most common musculoskeletal dysfunctions. Stroboscopic vision (SV) training has been deemed to enhance somatosensorial pathways in this population group; nevertheless, until recently no studies have addressed the additional effects of this treatment option to the traditional therapeutic approach.

METHODS

To evaluate the effectiveness of a partial visual deprivation training protocol in patients with CAI, a randomized controlled trial was carried out. Patients with CAI (n = 73) were randomized into either a balance training, SV training, or a control (no training) group. For participants assigned into training groups, they received 18 training sessions over 6 weeks. The primary outcome was dynamic balance as measured by the Star Excursion Balance Test assessed at baseline and after 6 weeks of intervention. Secondary outcome measures included ankle dorsiflexion range of motion, self-reported instability feeling, and ankle functional status.

RESULTS

Better scores in stroboscopic training and balance training groups in all outcome measures were observed in comparison with the control group with moderate to large effect sizes. Stroboscopic training was more effective than neuromuscular training in self-reported instability feeling (cohen's d = 0.71; p = 0.042) and anterior reach distance of the star excursion balance test (cohen's d = 1.23; p = 0.001).

CONCLUSIONS

Preliminary findings from the effects of SV Stroboscopic training in patients with CAI, suggest that SV may be beneficial in CAI rehabilitation.

Visuo-postural dependency index (VPDI) in human postural control

Background

Computerized stabilometry has been utilized to investigate the effect of vision on the neuromechanisms of human postural control. However, this approach lacks operational methods to quantify visual dependency during upright stance. This study had three goals: (1) To introduce the concept of visuo-postural dependency indices (VPDI) representing balance sway characteristics in multiple analytical domains (spatial, temporal, frequency, and structural), (2) To investigate the age and gender effects on VPDIs, and (3) To investigate the degree of relationships between VPDI and both subjective visual vertical and horizontal perception (SVV and SVH, respectively).

Methods

102 participants (16 to 80 years old) performed bipedal stances on a force platform with eyes open and closed. Response variables included the VPDIs computed for each postural index. In addition, 29 participants also performed SVV and SVH assessments.

Results

Fifteen VPDIs showed to be robust indicators of visual input modulation, and the variation across their magnitudes of modulation revealed a non-homogeneous response to changes in visual stimuli. Gender and age were not found to be a significant factor to VPDI modulation.

Conclusions

VPDIs revealed to be potential measures capable to quantitatively assess visuo-postural dependency and aid the assessment of fall risks and balance impairments.

The Effects of Active Self-correction on Postural Control in Girls with Adolescent Idiopathic Scoliosis: The Role of an Additional Mental Task

Due to balance deficits that accompany adolescent idiopathic scoliosis (AIS), the potential interaction between activities of daily living and active self-correction movements (ASC) on postural control deserves particular attention. Our purpose was to assess the effects of ASC movements with or without a secondary mental task on postural control in twenty-five girls with AIS. It is a quasi-experimental within-subject design with repeated measures ANOVA. They were measured in four 20-s quiet standing trials on a force plate: no task, ASC, Stroop test, and both. Based on the center-of-pressure (COP) recordings, the COP parameters were computed. The ASC alone had no effect on any of the postural sway measures. Stroop test alone decreased COP speed and increased COP entropy. Performing the ASC movements and Stroop test together increased the COP speed and decreased COP entropy as compared to the baseline data. In conclusion, our results indicate that AIS did not interfere with postural control. The effects of the Stroop test accounted for good capacity of subjects with AIS to take advantage of distracting attentional resources from the posture. However, performing both tasks together exhibited some deficits in postural control, which may suggest the need for therapeutic consultation while engaging in more demanding activities.

Interference of Visual Conditions and Stance Postures on Center of Pressure Sway in Patients with Schizophrenia with History of Fall

This study examines the interaction effects among incidences of falls, visual conditions, and stance postures on the magnitude of center of pressure sway (MCOPS) in patients with schizophrenia. The coordinates of COP in ten postural control demands were measured in subjects with at least one or without any falls in the previous year. MCOPS was calculated by the default program in Balance 3.78 software. Cognitive functions were also measured. The findings include: (1) the MCOPS increased as the postural control demands increase in subjects who have fallen; (2) MCOPS in subjects without falls was the largest for the lowest postural control demands; (3) MCOPS increased when the eyes were closed in subjects without a history of falls but decreased in subjects with a history of falls; (4) cognition function in subjects who have fallen was inferior to that in those without falls. The interference visual condition and stance postures on MCOPS tended to be different in schizophrenia with or without incidences of falls indicating the possible association between psychomotor dysfunction and falls in the subjects.

Center of pressure progression patterns during level walking in adolescents with idiopathic scoliosis

The purpose of this study was to determine whether functional walking performance measured with Timed Up-and-Go (TUG) and center of pressure (CoP) progression pattern is different across adolescents with various curve severity of idiopathic scoliosis (IS). The CoP coordinates during a stance phase for self-paced level walking between adolescent with three different severities of IS (mild IS, moderate IS, and severe IS) and age-matched normal subjects were measured with foot pressure measurement. The average data of three trials were compared among groups with repeated measure analysis of variance. Results showed that the TUG was different between normal and AIS subjects, indicating use of TUG as a marker of functional walking performance in AIS is plausible but studies with larger sample size is needed before using TUG to identify AIS with different scoliosis severity. The results also showed that the CoP displacement, velocity and acceleration during a stance phase was different across groups, and with the most prominent deviations found in the moderate IS group. The medial-lateral shifting of the CoP trajectory at mid-foot regions in all IS groups deviated the most. A tendency of asymmetry in CoP progression pattern between feet in IS groups was also found. The deviation of the spine alignment in frontal plane could change the CoP progression patterns during level walking, suggesting the risk of the locomotors subjecting to abnormal loading during daily walking. Education and conservative interventions might be needed for preservation of medical outcome and prevention of back pain and/or musculoskeletal consequences later in the lives of AIS with and without surgical correction.