Cortical activity associated with the maintenance of balance during unstable stances.

Background: Humans continuously maintain and adjust posture during gait, standing, and sitting. The difficulty of postural control is reportedly increased during unstable stances, such as unipedal standing and with closed eyes. Although balance is slightly impaired in healthy young adults in such unstable stances, they rarely fall. The brain recognizes the change in sensory inputs and outputs motor commands to the musculoskeletal system. However, such changes in cortical activity associated with the maintenance of balance following periods of instability require further clarified. Methods: In this study, a total of 15 male participants performed two postural control tasks and the center of pressure displacement and electroencephalogram were simultaneously measured. In addition, the correlation between amplitude of center of pressure displacement and power spectral density of electroencephalogram was analyzed. Results: The movement of the center of pressure was larger in unipedal standing than in bipedal standing under both eye open and eye closed conditions. It was also larger under the eye closed condition compared with when the eyes were open in unipedal standing. The amplitude of high-frequency bandwidth (1-3 Hz) of the center of pressure displacement was larger during more difficult postural tasks than during easier ones, suggesting that the continuous maintenance of posture was required. The power spectral densities of the theta activity in the frontal area and the gamma activity in the parietal area were higher during more difficult postural tasks than during easier ones across two postural control tasks, and these correlate with the increase in amplitude of high-frequency bandwidth of the center of pressure displacement. Conclusions: Taken together, specific activation patterns of the neocortex are suggested to be important for the postural maintenance during unstable stances.

Effects of auditory noise intensity and color on the dynamics of upright stance.

Previous work assessing the effect of additive noise on the postural control system has found a positive effect of additive white noise on postural dynamics. This study covers two separate experiments that were run sequentially to better understand how the structure of the additive noise signal affects postural dynamics, while also furthering our knowledge of how the intensity of auditory stimulation of noise may elicit this phenomenon. Across the two experiments, we introduced three auditory noise stimulations of varying structure (white, pink, and brown noise). Experiment 1 presented the stimuli at 35 dB while Experiment 2 was presented at 75 dB. Our findings demonstrate a decrease in variability of the postural control system regardless of the structure of the noise signal presented, but only for high intensity auditory stimulation.

Stroke walking and balance characteristics via principal component analysis.

Balance impairment is associated gait dysfunction with several quantitative spatiotemporal gait parameters in patients with stroke. However, the link between balance impairments and joint kinematics during walking remains unclear. Clinical assessments and gait measurements using motion analysis system was conducted in 44 stroke patients. This study utilised principal component analysis to identify key joint kinematics characteristics of patients with stroke during walking using average joint angles of pelvis and bilateral lower limbs in every gait-cycle percentile related to balance impairments. Reconstructed kinematics showed the differences in joint kinematics in both paretic and nonparetic lower limbs that can be distinguished by balance impairment, particularly in the sagittal planes during swing phase. The impaired balance group exhibited greater joint variability in both the paretic and nonparetic limbs in the sagittal plane during entire gait phase and during terminal swing phase respectively compared with those with high balance scores. This study provides a more comprehensive understanding of stroke hemiparesis gait patterns and suggests considering both nonparetic and paretic limb function, as well as bilateral coordination in clinical practice. Principal component analysis can be a useful assessment tool to distinguish differences in balance impairment and dynamic symmetry during gait in patients with stroke.

Effectiveness of sensor-based interventions in improving gait and balance performance in older adults: systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Sensor-based interventions (SI) have been suggested as an alternative rehabilitation treatment to improve older adults' functional performance. However, the effectiveness of different sensor technologies in improving gait and balance remains unclear and requires further investigation. METHODS: Ten databases (Academic Search Premier; Cumulative Index to Nursing and Allied Health Literature, Complete; Cochrane Central Register of Controlled Trials; MEDLINE; PubMed; Web of Science; OpenDissertations; Open grey; ProQuest; and Grey literature report) were searched for relevant articles published up to December 20, 2022. Conventional functional assessments, including the Timed Up and Go (TUG) test, normal gait speed, Berg Balance Scale (BBS), 6-Minute Walk Test (6MWT), and Falling Efficacy Scale-International (FES-I), were used as the evaluation outcomes reflecting gait and balance performance. We first meta-analyzed the effectiveness of SI, which included optical sensors (OPTS), perception sensors (PCPS), and wearable sensors (WS), compared with control groups, which included non-treatment intervention (NTI) and traditional physical exercise intervention (TPEI). We further conducted sub-group analysis to compare the effectiveness of SI (OPTS, PCPS, and WS) with TPEI groups and compared each SI subtype with control (NTI and TPEI) and TPEI groups. RESULTS: We scanned 6255 articles and performed meta-analyses of 58 selected trials (sample size = 2713). The results showed that SI groups were significantly more effective than control or TPEI groups (p < 0.000) in improving gait and balance performance. The subgroup meta-analyses between OPTS groups and TPEI groups revealed clear statistically significant differences in effectiveness for TUG test (mean difference (MD) = - 0.681 s; p < 0.000), normal gait speed (MD = 4.244 cm/s; p < 0.000), BBS (MD = 2.325; p = 0.001), 6MWT (MD = 25.166 m; p < 0.000), and FES-I scores (MD = - 2.036; p = 0.036). PCPS groups also presented statistically significant differences with TPEI groups in gait and balance assessments for normal gait speed (MD = 4.382 cm/s; p = 0.034), BBS (MD = 1.874; p < 0.000), 6MWT (MD = 21.904 m; p < 0.000), and FES-I scores (MD = - 1.161; p < 0.000), except for the TUG test (MD = - 0.226 s; p = 0.106). There were no statistically significant differences in TUG test (MD = - 1.255 s; p = 0.101) or normal gait speed (MD = 6.682 cm/s; p = 0.109) between WS groups and control groups. CONCLUSIONS: SI with biofeedback has a positive effect on gait and balance improvement among a mixed population of older adults. Specifically, OPTS and PCPS groups were statistically better than TPEI groups at improving gait and balance performance, whereas only the group comparison in BBS and 6MWT can reach the minimal clinically important difference. Moreover, WS groups showed no statistically or clinically significant positive effect on gait and balance improvement compared with control groups. More studies are recommended to verify the effectiveness of specific SI. Research registration PROSPERO platform: CRD42022362817. Registered on 7/10/2022.

Effect of low versus high balance training complexity on balance performance in male adolescents.

OBJECTIVE: The current study aimed to determine the effects of low (i.e., balance task only) versus high (i.e., balance task combined with an additional motor task like dribbling a basketball) balance training complexity (6 weeks of training consisting of 2 × 30 min balance exercises per week) on measures of static and dynamic balance in 44 healthy male adolescents (mean age: 13.3 ± 1.6 years). RESULTS: Irrespective of balance training complexity, significant medium- to large-sized pretest to posttest improvements were detected for static (i.e., One-Legged Stance test, stance time [s], 0.001 < p ≤ 0.008) and dynamic (i.e., 3-m Beam Walking Backward test, steps [n], 0.001 < p ≤ 0.002; Y-Balance-Test-Lower-Quarter, reach distance [cm], 0.001 < p ≤ 0.003) balance performance. Further, in all but one comparison (i.e., stance time with eyes opened on foam ground) no group × test interactions were found. These results imply that balance training is effective to improve static and dynamic measures of balance in healthy male adolescents, but the effectiveness seems unaffected by the applied level of balance training complexity.

Acute responses of postural alignment and intermuscular coherence to anti-gravitational muscle engagement-A randomized crossover trial.

INTRODUCTION: Posture is a facet of clinical assessment in several rehabilitative disciplines. Despite extensive clinical focus, the precision with which posture can be evaluated and intervened upon is limited by the very general terms used to describe it. The purpose of this crossover trial was to quantify the effects of targeted postural intervention motivated by theoretical sagittal gravitational collapsing (SGC) tendencies on: 1) distance from SGC, 2) intermuscular coherence (iCOH), and 3) kinematic chain connectivity. METHODS: Ten healthy adults (24.50 ± 1.18 years, 172.72 ± 10.19 cm, 76.47 ± 14.60 kg) completed pre- and post-intervention testing on two occasions involving contrasting interventions: promote postural muscle (PPM) vs. reduce compensatory muscle (RCM) engagement. Distance from SGC, iCOH, and kinematic chain connectivity were quantified from electromyography and/or kinematic data acquired during tests administered before and after interventions. Effects of Treatment [PPM, RCM] and Time [Pre, Post] were tested with linear mixed models. RESULTS: A Treatment*Time interaction was observed for distance from SGC. Post-intervention distance from SGC was greater following PPM only (p < 0.01). A Treatment*Time interaction was observed for hi-frequency trunk muscle iCOH, with a post-intervention increase corresponding to the RCM intervention (p < 0.007). Additional iCOH effects did not differ by intervention. CONCLUSION: Distance from SGC is acutely modifiable and increases following exercises to facilitate anti-SGC muscles. Convergent findings related to kinematic chain connectivity and prescriptive neural binding were not observed. These observations suggest that it may be possible to describe, evaluate, and intervene upon posture in reference to a specific, mechanistic theory regarding the function of postural alignment.

Are lower limb symmetry and self-reported symptoms associated with functional and neuromuscular outcomes in Brazilian adults with anterior cruciate ligament reconstruction? A cross-sectional study.

INTRODUCTION: After anterior cruciate ligament (ACL) reconstruction, determining readiness to return to participation is challenging. The understanding of which neuromuscular performance parameters are associated with limb symmetry and self-reported symptoms may be useful to improve monitoring the rehabilitation towards adequate decision-making to return. OBJECTIVES: To compare the ACL-operated and injury-free lower limbs regarding functional performance; and to investigate whether lower limb strength and functional performance are associated with self-reported symptoms and functional lower limb symmetry. METHOD: Thirty-four participants were included. Functional performance was assessed by using the Y-Balance test, Single-leg Hop, and Functional Movement Screen. An isokinetic dynamometer was used to evaluate the strength levels in open and closed kinetic chains. The functional lower limb symmetry was calculated considering the single-leg hop test results for each lower limb. RESULTS: There were no differences in dynamic balance (Y-Balance) between the operated and injury-free limbs. The operated limb presented a worst performance in the single-leg hop. Self-reported symptoms prevalence and lower limb symmetry were associated with knee extension strength and functional performance (Y-Balance). CONCLUSION: Individuals submitted to ACL-reconstruction presented worse functional performance in the operated limb compared to the injury-free limb. Both knee strength and dynamic balance were associated with limb symmetry and self-reported symptoms.

Differences and correlations between horizontal and vertical single-leg jump performance, dynamic balance, and ankle dorsiflexion range of motion in male amateur rugby players according to playing positions.

OBJECTIVES: To explore the differences and correlations in the Y-Balance Test (YBT) scores, ankle-dorsiflexion range of motion (ADFROM), single-leg drop jump (SLDJ) and single-leg hop for distance (SLHD) in amateur male rugby players by playing positions and limb dominance. DESIGN: Cross-sectional study. SETTING: Argentinian amateur rugby club. PARTICIPANTS: Male (n = 58) senior amateur rugby players. MAIN OUTCOME MEASURES: ADFROM, YBT (anterior [AN], posteromedial, posterolateral, and composite [COM]), SLDJ and SLHD performances. RESULTS: Forwards demonstrated different anthropometric traits than backs (p < 0.001 to 0.003; ES: -0.508 to -1.331), whereas the latter attained better jump performance (p < 0.001-0.05; ES: 0.297-1.349) and YBTCOM scores compared to the former, irrespective of limb dominance (p: 0.007-0.034; ES: 0.569-0.730). With regards to the associations, forwards' BMI (rho: -0.35 to -0.52, ES: 0.184) and ADFROM values (rho: 0.41 to 0.53, ES: 0.184; r: 0.43 to 0.50, ES: 0.184) were associated to jump performance among both limbs. In contrast, for the backs, leg length was associated with SLHD (rho: 0.42-0.45, ES: 0.214) and YBTCOM (rho: -0.67 to -0.76, ES: 0.215). Likewise, ADFROM values (r: 0.44-0.56, ES: 0.185) were moderately associated to YBTAN in both limbs. CONCLUSIONS: Backs attained better dynamic balance, wider ADFROM, and better unilateral vertical and horizontal jumps performances in dominant and non-dominant limb, compared to forwards. Additionally, ADFROM maybe an important aspect to consider when aiming to improve balance and jump performance among forwards and backs.

Pain and disability were related to Y-balance test but not with proprioception acuity and single-leg triple-hop test in patients with patellofemoral pain: A cross-sectional study.

INTRODUCTION: Patellofemoral pain is a common complaint between physically active subjects. Patients with patellofemoral pain present limitations to performing daily activities. Pain could alter proprioceptive acuity and lead to movement impairment. The aim of this study was to investigate the relationship of pain and disability with proprioception acuity and physical performance in patients with patellofemoral pain. METHODS: Forty-eight patients with patellofemoral pain [age 31.15 (5.91) years; 30 (62.50%) males] were recruited. Data collected included pain intensity, pain duration, disability, joint position sense (JPS) test at 20° and 60° of knee flexion, and physical performance tests (Single-Leg Triple-Hop Test and Y- Balance Test). Spearman's rank correlation coefficient (rs) and 95% confidence intervals (CI) were computed to assess the relationship between the variables. RESULTS: Pain intensity was correlated with Y-Balance Test posteromedial component (rs = -0.32, 95%CI = -0.55 to -0.03, p = 0.029) and the composite score (rs = -0.35, 95%CI = -0.58, -0.07, p = 0.015). Pain duration was correlated with Y-Balance Test posterolateral component (rs = -0.23, 95% CI = -0.53 to -0.01, p = 0.047). Disability was correlated with Y-Balance Test posteromedial component (rs = 0.41, 95% CI = 0.14 to 0.62, p = 0.004). Pain and disability were not correlated with JPS and the Single-Leg Triple-Hop Test. CONCLUSION: Pain and disability were related to Y-Balance Test but not to proprioceptive acuity and Single-Leg Triple-Hop Test in patients with patellofemoral pain.

Investigating scapula positioning in individuals with non-specific lower back pain: A preliminary study.

INTRODUCTION: Low back pain (LBP) is an economic and physically disabling burden on individuals and society. With 70% of cases classed as non-specific, there is a need for further research into the causes and consequences associated. The involvement of postural balance in musculoskeletal conditions is gaining increasing interest in research and health practice. However, there is a lack of literature surrounding LBP and posture in distal segments of the body. OBJECTIVE: The current study investigated scapula positioning in those with non-specific LBP. METHODS: Scapula angle of rotation, scapula protraction, and scapula elevation were assessed in nine participants with chronic non-specific LBP and compared with that of nine asymptomatic controls (aged 18-60 years). The degree of pelvic tilt was assessed across both groups as a secondary outcome measure. RESULTS: No difference was identified between the two sample groups for scapula angle of rotation (p = 0.707), protraction (p = 0.755), or elevation (p = 0.691). Anterior pelvic tilt was greater in those with LBP (p = 0.046), supporting previous literature. CONCLUSION: The findings for the scapula position are novel, given that research in this field is limited. It is concluded that there is no change in scapula positioning in those with non-specific LBP, but there is an increased anterior pelvic tilt.

Accuracy to identify young adults with chronic ankle instability using a virtual reality - Balance error scoring system: A cross-sectional study.

INTRODUCTION: The Balance Error Scoring System (BESS) assesses the ability to control postural stability by performing 3 different stances on two-type surfaces during closed eyes. Virtual reality technology combined with the BESS test (VR-BESS) may be used to disrupt visual inputs instead of closing the eyes, which may improve the sensitivity of diagnosing patients with chronic ankle instability (CAI). OBJECTIVE: This study aimed to evaluate the accuracy to identify individuals with CAI of the VR-BESS test comparing with the original BESS test. METHODS: The BESS and VR-BESS tests were administered to 68 young adults (34 participants with CAI and 34 without CAI). Frontal and lateral video views were used to measure the participant's performance errors. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was computed to determine the diagnostic test's overall accuracy. RESULTS: The total score of the BESS test and the VR-BESS test were statistically significant in comparison to the AUC of no discrimination at 0.5, with AUC values of 0.63 and 0.64, respectively. The cut-off scores for the BESS and VR-BESS tests were 12 and 15, respectively. There was no significant difference between the ROC curves of the BESS and the VR-BESS test for identifying individuals with CAI. CONCLUSION: The BESS and VR-BESS tests may be utilized interchangeably to identify individuals with CAI.

What is the influence of biomechanical variables on the Y balance test performance in recreational runners?

BACKGROUND: Asymmetries and poor Y balance test (YBT) performance are associated with an increased risk of injuries in athletes. The aim of this study was to investigate the association between YBT performance with biomechanical variables in runners. METHODS: The runners underwent the YBT, followed by the assessment of center of pressure, plank position, muscle strength (MS) of hip flexors, extensors, abductors, and external rotators, knee extensors, ankle dorsiflexion range of motion (ROM), Q angle, forefoot alignment, and passive hip internal rotation. Associations between variables were examined using multiple linear regression models with the Bayesian Information Criterion. RESULTS: 122 cases were analyzed. The R2 values were 0.38; 0.05; 0.06; and 0.15 for the anterior, posteromedial, posterolateral and composite directions models, respectively. The anterior reach in the YBT was associated with ankle dorsiflexion ROM [Sß 95%IC: 0.43 (0.32-0.55)], passive hip internal rotation [Sß 95%IC: 0.35 (0.24-0.47)], MS of the hip extensors [Sß 95%IC: 0.19 (0.07-0.31)] and forefoot alignment [Sß 95%IC: 0.14 (-0.25-0.02)]. The posteromedial and posterolateral reach were associated with MS of the hip flexors [Sß 95%IC: 0.23 (0.09-0.37) and 0.24 (0.11-0.38)], respectively. The composite score was associated with MS of the hip flexors [Sß 95%IC: 0.31 (0.18-0.45)], ankle dorsiflexion ROM [Sß 95%IC: 0.24 (0.10-0.37)] and Q angle [Sß 95%IC: 0.18 (0.04-0.31)]. CONCLUSION: YBT performance in different directions demonstrated specific associations with key biomechanical factors.

Comparative analysis of postural stability and risk of falling and developing disability among overweight and obese women over 40 years.

BACKGROUND: Increased body mass index (BMI) adversely affects the mechanics of the musculoskeletal system. It is known that obese people have poorer postural stability and mobility-related outcomes compared to normal weight people, but there is limited research comparing overweight and class 1 obese people, two consecutive and prevalent BMI categories. AIMS: To compare postural stability, functional mobility, and risk of falling and developing disability between overweight and obese women, and to investigate the relationship of BMI and body weight with the outcomes. METHODS: Thirty women with class 1 obesity and 30 overweight women were included. Standing postural stability with eyes-open and eyes-closed and stability limits were assessed using the Prokin system. The Timed Up and Go Test (TUG) was used to assess functional mobility and risk of falling (≥11 s) and developing disability (≥9 s). RESULTS: The average center of pressure displacements on the y-axis (COPY) obtained during quiet standing with both eyes-open and eyes-closed were higher in obese women than overweight women (p < 0.05) and the effect sizes were moderate for the results. The COPY values in the eyes-open and eyes-closed conditions were correlated with BMI (r = 0.295 and r = 0.285, p < 0.05). Furthermore, the COPX value in the eyes-open condition and the TUG score were correlated with body weight (r = 0.274 and r = 0.257, p < 0.05). CONCLUSIONS: Obese women had poorer static standing stability in the anteroposterior direction than overweight women, while functional mobility and risk of falling and developing disability did not differ. Furthermore, BMI and body weight were related to poorer static standing stability.

Ankle dorsiflexion range of motion and hip abductor strength can predict Lower Quarter Y-Balance Test performance in healthy males.

OBJECTIVES: The aim of the study was to assess whether strength and range of motion (ROM) of the hip and ankle are the factors determining performance in the Lower Quarter Y-Balance test (YBT-LQ). DESIGN: Cross-sectional study. PARTICIPANTS: 66 healthy males (age: 25.2±6.8 years) participated in this study. MAIN OUTCOME MEASURES: Participants underwent assessments of ankle dorsiflexion (DF) ROM, hip internal rotation (IR) ROM, external rotation (ER) ROM and isometric strength of hip abductor (ABD), extensor (EXT) and external rotators (ERS) muscles together with YBT-LQ for both legs. A forward 2-steps multiple linear regression analysis was conducted to examine the relationship between the predictor variables and the criterion variable. RESULTS: Ankle DF ROM predicted anterior (ANT) reach (R2 = 0.49; R2 = 0.33; p < 0.001). The model with hip ABD strength and ankle DF ROM explained posteromedial (PM) reach variance for stance leg (R2 = 0.35; p < 0.001), while only hip ABD strength was included for kicking leg (R2 = 0.19; p = 0.007). The model with ankle DF ROM and hip ABD strength explained posterolateral (PL) reach for stance leg (R2 = 0.41; p < 0.001). Hip ABD was the only predictor for kicking leg PL reach (R2 = 0.15; p < 0.001). YBT-LQ composite score was explained by ankle DF ROM and hip ABD strength for both legs (R2 = 0.44; p < 0.001) and (R2 = 0.25; p = 0.002). CONCLUSION: Hip ABD strength and ankle DF ROM can determine performance in the YBT-LQ. Strength of hip EXT, ERS as well as ROM of hip IR and ER did not predict YBT-LQ performance.

How virtual reality is impacting balance: An examination of postural stability.

BACKGROUND: The interest in virtual reality (VR) applications has been on the rise in recent years. However, the impact of VR on postural stability remains unclear. RESEARCH QUESTION: The study has two primary objectives: first, to compare postural stability in a 3D-immersed virtual reality environment (VE) and a real environment (RE), and second, to investigate the effect of positive and negative visual feedback, which are subconditions of VE on postural stability. METHODS: The observational study recruited 20 healthy adults (10 male, 10 female, 22.8 ± 1.8 years) who underwent postural stability assessments in both RE and VE. In VE, participants received visual stimuli in three different ways: without visual feedback, with positive and negative visual feedback that they would consider themselves to be directed towards postural stability outcomes. The RE included two conditions: eyes open (EO) and eyes closed (EC). Postural stability was evaluated with sway velocity, sway area, and perimeter variables obtained from a force platform. RESULTS: All postural stability variables were significantly lower in the RE than in the VE (p < 0.05). There was no significant difference between the VE and EC in terms of sway velocity and sway area (p > 0.05). The visual feedback in the VE did not affect participants' postural stability (p > 0.05). VE may cause an increase in postural sway variables compared to RE and postural requirements may be higher in VE compared to RE. SIGNIFICANCE: This is the first and only study examining the effect of different visual feedback on postural stability in VE.

Effects of core muscles strengthening exercises with routine physical therapy on trunk balance in stroke patients: A randomized controlled trial.

OBJECTIVE: To compare the effects of core muscle strengthening exercises with and without routine physical therapy on trunk balance in chronic stroke patients. METHODS: The randomised controlled trial was conducted at Mubarak Medical Complex, Sargodha, Pakistan, from October 28, 2021, to April 28, 2022, and comprised patients of either gender with chronic stroke aged 40-60 years. The subjects were randomised using the lottery method into group A that was managed with routine physical therapy, and group B which was further managed with core strengthening exercises. The intervention comprised 4 sessions per week for 8 weeks. Outcome was measured using Trunk Impairment Scale and Time Up and Go test. Data was collected at baseline, week 4 and post-intervention. Data was analysed using SPSS 23. RESULTS: Of the 80 individuals screened, 74(92.5%) were included. There were 37(50%) patients in group A; 30(81%) males and 7(19%) females with mean age 56.73±2.37 years. The remaining 37(50%) patients were in group B; 27(73%) males and 10(27%) females with mean age 55.65±2.88 years. Trunk balance and functional mobility improved significantly post-intervention in both groups (p<0.05), but group B values were significantly better compared to group A values (p<0.05). CONCLUSIONS: Core muscle strengthening exercises combined with routine physical therapy were found to be more effective compared to routine physical therapy alone in chronic stroke patients for improving trunk balance and functional mobility. Registration Number: IRCT20211116053070N1.

Spinal cord stimulation for postural abnormalities in Parkinson's disease: 1-year prospective pilot study.

BACKGROUND: Postural abnormalities (PA) are common in the advanced stages of Parkinson's disease (PD), but effective therapies are lacking. A few studies suggested that spinal cord stimulation (SCS) could be a potential therapy whereas its effect is still uncertain. We aimed to investigate whether SCS had potential for benefiting PD patients with PA. METHODS: T8-12 SCS was operated on six PD patients with PA and all patients were followed for one year. Evaluations were made before and after SCS. Moreover, three patients were tested separately with SCS on-state and off-state to confirm the efficacy of SCS. RESULTS: Improvements in lateral trunk flexion degree, anterior thoracolumbar flexion degree and motor function were found after SCS. The improvements diminished while SCS was turned off. CONCLUSIONS: Lower thoracic SCS may be effective for improving PA in PD patients, but further studies are needed to confirm this conclusion. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1900024326, Registered on 6th July 2019; https://www.chictr.org.cn/showproj.aspx?proj=40835 .

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.

Introduction to the assessment and management of persistent postural-perceptual dizziness.

OBJECTIVE: Persistent postural-perceptual dizziness classifies patients with chronic dizziness, often triggered by an acute episode of vestibular dysfunction or threat to balance. Unsteadiness and spatial disorientation vary in intensity but persist for over three months, exacerbated by complex visual environments. METHOD: Literature suggests diagnosis relies on a clinical history of persistent subjective dizziness and normal vestibular and neurological examination findings. Behavioural diagnostic biomarkers have been proposed, to facilitate diagnosis. RESULTS: Research has focused on understanding the neural mechanisms that underpin this perceptual disorder, with imaging data supporting altered connectivity between neural brain networks that process vision, motion and emotion. Behavioural research identified the perceptual and motor responses to a heightened perception of imbalance. CONCLUSION: Management utilises head and body motion detection, and downregulation of visual motion excitability, reducing postural hypervigilance and anxiety. Combinations of physical and cognitive therapies, with antidepressant medications, help if the condition is associated with mood disorder.

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.