Altered Postural Control Research Articles

Levodopa-induced dyskinesia alters postural control in people with Parkinson’s disease

While levodopa is the most effective drug for symptom treatment of Parkinson’s Disease (PD), its long-term use often leads to side effects such as uncontrolled involuntary movements known as levodopa-induced dyskinesia (LID). LID has been shown to increase postural sway, but the extent to which these hyperkinetic movements alter postural sway strategies has not been explored. We recruited 25 people with idiopathic PD, of which 13 exhibit clinical signs of LID, and 10 healthy older adults. Participants performed thirty-second standing trials with no added task (single-task) and with performing a cognitive dual-task, known to provoke dyskinesia. Participants with PD were tested in their practical OFF and ON states. The root-means-square (RMS) accelerations were obtained from inertial sensors attached to the lumbar, trunk, and head. Sway ratios (superior-to-inferior segment) were calculated to determine the effect of LID on postural sway strategies. Participants with LID showed greater RMS head sway, compared to those without LID and older adults. The head-to-trunk sway ratio was greater in participants with LID during the ON state or when dual-tasking. In addition, the head-to-lumbar sway ratio was greater in participants with LID in the ON state during both single- and dual-tasking. Our results reveal an altered postural control strategy in PD with LID, presenting increased sway in superior segments of the kinematic chain, leading to head instability. Unlike PD without LID and older adults, PD with LID exhibit multi-link sway in the ON state, which has important implications for measuring postural sway in the presence of dyskinesias.

Validation of a laser visual feedback and core stability exercise programme to improve lateropulsion reduction and pushing intensity in stroke patients with pusher syndrome: A Delphi study.

The patient with pusher syndrome (PS) is characterized by showing postural control alterations due to a lack of perception of his own body in the space. It appears when the patient actively pushes with his unaffected limbs towards the injured side, reacting with resistance to passive straightening towards the midline. Between 10% and 50% of strokes present PS. Nowadays, there is no clearly defined treatment for PS. To design and validate an exercise program using visual feedback and specific core stability exercises (FeViCoS) for the treatment of patients with PS. Validation was conducted by expert consensus using the Delphi method. Thirteen neurorehabilitation experts participated in the process. An online questionnaire with 18 Likert-type questions was used to evaluate the designed program. Consensus was considered reached if there was convergence between the quartile 1 and 3 values (RIQ=Q1-Q3) or if the relative interquartile range (RIR) was less than 20%. The degree of agreement between experts was measured by calculating the Fleiss' kappa coefficient. A total of 2 rounds were required to achieve 97.44% consensus with 100% participation. The RIR was less than or equal to 20% for all questions. The Fleiss' kappa index (0.831) showed that the degree of agreement between experts was excellent. Neurorehabilitation experts considered FeViCoS valid for the therapeutic approach to patients with PS. Expert consensus suggests a novel strategy in physical therapy clinical practice to improve balance and postural orientation in patients with subacute stroke and PS.

A prospective investigation of the effects of soccer heading on cognitive and sensorimotor performances in semi-professional female players.

Repetitive head impacts (RHI) from routine soccer (football) heading have been suggested to contribute to the long-term development of neurodegenerative disorders. However, scientific evidence concerning the actual risk of these RHI on brain health remains inconclusive. Moreover, female athletes-despite a presumably increased vulnerability toward the effects of RHI-are largely underrepresented in previous approaches. Therefore, our aim was to prospectively investigate the effects of heading on cognitive and sensorimotor performances, health perception, and concussion symptoms in semi-professional female soccer players. An extensive test battery was used to assess cognitive and sensorimotor performances as well as health status (SF-36) and concussion symptoms (SCAT3) of a total of 27 female soccer players (22.2 ± 4.2 years) and 15 control subjects (23.2 ± 3.0 years) before and after one-and-a-half years. Throughout this period, soccer players' heading exposure was determined using video analysis. Subgroup comparisons (control [n = 12], low exposure [n = 7], high exposure [n = 8]) showed no time-dependent differences in SF-36 or SCAT3 scores. Similarly, across most behavioral tests, soccer players' performances evolved equally or more favorably as compared to the control subjects. However, there were significant effects pointing toward slightly negative consequences of heading on aspects of fine motor control (p = 0.001), which were confirmed by correlation and multiple regression analyses. The latter, further, yielded indications for a relationship between heading exposure and negative alterations in postural control (p = 0.002). Our findings do not provide evidence for negative effects of soccer heading on female players' health perception, concussion symptoms, and cognitive performances over the course of one-and-a-half years. However, we found subtle negative alterations in fine motor and postural control that could be attributed to heading exposure. Other factors, like the number of previous head injuries, were not linked to the observed changes. Given the reduction of our initial sample size due to player fluctuation, the results need to be interpreted with caution and validated in larger-scale studies. These should not only focus on cognitive outcomes but also consider sensorimotor changes as a result of RHI from soccer heading.

Postural Control and Weight Bearing Symmetry Patterns in Patients Post Lumbar Spinal Decompression Surgery

Background Prolapsed intervertebral disc is one of the most common reasons for low back pain often causing altered postural control and weight bearing symmetry of foot. Although these components are known to be affected there is limited literature available explaining the postural control and weight bearing symmetry post spinal decompression surgical procedures.Objective The study was formulated with the objective to understand postural control and symmetry of weight bearing patterns among patients post lumbar spinal decompression surgery.Methods The study was conducted involving 65 patients who were assessed pre-and post-lumbar decompression surgery. Nintendo Wii balance board was used to assess the patients at all intervals.Results The post-surgical values at discharge showed a clinical improvement in postural control bilaterally left P0.068 and right P0.031 but showed deterioration at one month with right P0.076 and significant on left side P0.009. Contrary to this the follow up values at one month showed a significant improvement in weight bearing symmetry P0.001. Pain values both on activity and at rest taken at both follow-up intervals F1 and F2 showed a statistically significant reduction P0.001.Conclusion Postural control assessed with single limb stance shows worsening at one month post decompression procedure. Weight bearing symmetry parameters may demonstrate a decline immediately post lumbar decompression surgery but may show a significant improvement along with reduction in pain post surgically as early as one month.

EMG Analysis During Static Balance in Chronic Ankle Instability, Coper and Controls.

Patients with chronic ankle instability (CAI) consistently display postural control alterations, which may result from sensorimotor dysfunction. This study aimed to compare muscle activity in the lower extremity and postural control among individuals with CAI, copers and uninjured controls during a static balance test. A total of 57 physically active participants were categorized into three groups (CAI, copers and controls) and performed a single-leg balance test with two visual conditions: eyes open and eyes closed. Muscle activity in six lower extremity muscles and center of pressure (CoP) variables were recorded and analyzed. Patients with CAI exhibited greater muscle activity in the medial gastrocnemius and gluteus maximus compared to controls or copers, regardless of the visual condition. Copers displayed increased gluteus medius activity compared to controls. Additionally, all groups demonstrated increased muscle activity and CoP variables when visual feedback was disrupted. These findings suggest that patients with CAI may have less effective recruitment of motor units during static balance. On the other hand, greater muscle activity in the gluteus medius in copers may represent a coping mechanism to avoid further ankle injuries. Further research on muscle activity during dynamic postural control is warranted to explore sensorimotor alterations in patients with CAI.

Dynamic postural control in women athletes with and without nonspecific low back pain with high and low pain-related anxiety- A case-control study

BackgroundLow back pain is common among athletes and it has been shown that postural control is altered in the general population with nonspecific low back pain (NSLBP). Psychological factors may also predispose individuals to risk of altered postural control. Dynamic postural control is essential to the performance of athletes. This study aimed to compare the dynamic postural control between women athletes with and without NSLBP with high and low pain-related anxiety.MethodsForty-five female athletes (15 NSLBP with high pain-related anxiety, 15 NSLBP with low pain-related anxiety, and 15 healthy (control)) were included. Pain-related anxiety was assessed using the Pain Anxiety Symptom Scale-20 (PASS-20). Based on the cut-off score of 30 for the total score of PASS-20, NSLBP patients were classified into two groups of low and high pain-related anxiety. Participants performed double-leg vertical drop jump (DVJ) and single-leg vertical jump (SVJ) tests on a Kistler force plate (type 9260AA6, Kistler Instruments Inc, Switzerland). The total root mean square (RMS) of the center of pressure (COP), COP displacement in the anteroposterior (AP), and mediolateral (ML) directions, COP mean velocity, and time to stabilization (TTS) in vertical, AP, and total directions were extracted from COP and ground reaction force data using MATLAB software. One-way Analysis of variance (ANOVA) and Welch’s ANOVA were employed to compare the groups. In case of significant findings, post hoc tests were performed.ResultsThe results showed that during DJV, athletes with high pain-related anxiety had significantly greater TTS in all total, AP, and ML directions than other groups (P < 0.05). Also, the control group showed greater total RMS distance during DJV than either NSLBP group. However, no significant differences in TTS and COP parameters were found between the groups during SVJ (P > 0.05).ConclusionsThe findings suggest that pain-related anxiety may contribute to athletes’ postural control strategies. Therefore, it is important to consider the level of pain-related anxiety during planning postural control exercises for women athletes with NSLBP.

Effect of autogenous osteochondral mosaicplasty on the balance control of patients with cartilage defects of the knee: a pilot study

BackgroundAutogenous osteochondral mosaicplasty (AOM) is a widely used optimal surgical technique for cartilage repair in young patients with focal articular cartilage defects. However, the alterations in balance control in these patients after AOM have not been sufficiently investigated. This study aimed to compare different balance control performances between the patients with knee cartilage defects and healthy controls before and after AOM, as well as evaluate the influence of AOM on balance control in these patients.MethodsStatic posturographic tests were performed in twenty-four patients who were scheduled for AOM two weeks pre-, three months, and one year postoperatively, along with thirty matched controls, respectively. All participants underwent posturography under four standing conditions: eyes open and closed, without and with foam support to assess the balance control ability. Subsequently, patient-reported outcome measures (PROMs) were synchronously obtained and analyzed.ResultsCompared to the control subjects, less efficient balance control was observed in study patients at three testing phases (p < 0.05), whereas no alterations in postural control were visible in these patients within a year following AOM (p > 0.05). Significant improvements were found in all PROMs such as the International Knee Documentation Committee, the Lysholm Knee Score, and the visual analogue scale in the study patients postoperatively (p < 0.01).ConclusionThe results indicated that patients with knee cartilage defects have a prominent balance control deficit compared to healthy individuals. Furthermore, AOM does not improve balance control in these patients for at least one year postoperatively, and more effective approaches for postural regulation are required for the management of cartilage defect patients.

Characterization of Postural Sway in Women with Osteoporosis and a Control Group by Means of Linear and Nonlinear Methods.

The mechanisms underlying the altered postural control and risk of falling in patients with osteoporosis are not yet fully understood. The aim of the present study was to investigate postural sway in women with osteoporosis and a control group. The postural sway of 41 women with osteoporosis (17 fallers and 24 non-fallers) and 19 healthy controls was measured in a static standing task with a force plate. The amount of sway was characterized by traditional (linear) center-of-pressure (COP) parameters. Structural (nonlinear) COP methods include spectral analysis by means of a 12-level wavelet transform and a regularity analysis via multiscale entropy (MSE) with determination of the complexity index. Patients showed increased body sway in the medial-lateral (ML) direction (standard deviation in mm: 2.63 ± 1.00 vs. 2.00 ± 0.58, p = 0.021; range of motion in mm: 15.33 ± 5.58 vs. 10.86 ± 3.14, p = 0.002) and more irregular sway in the anterior-posterior (AP) direction (complexity index: 13.75 ± 2.19 vs. 11.18 ± 4.44, p = 0.027) relative to controls. Fallers showed higher-frequency responses than non-fallers in the AP direction. Thus, postural sway is differently affected by osteoporosis in the ML and AP directions. Clinically, effective assessment and rehabilitation of balance disorders can benefit from an extended analysis of postural control with nonlinear methods, which may also contribute to the improvement of risk profiles or a screening tool for the identification of high-risk fallers, thereby prevent fractures in women with osteoporosis.

Postural Control Alterations in Children with Mild Forms of Spastic Cerebral Palsy.

To determine the postural control responses' differences between children with mild spastic Cerebral Palsy (CP) and children who are typically developing (TD). Children with spastic CP, Level I-II (n=20, mean age=9.42±4.59 years, 50% girls, 50% boys) and children with TD (N=20, mean age=9.65±3.03, 55% girls, 45% boys) were included in the study. All participants were evaluated with Computerized Dynamic Posturography, Sensory Organization Test (SOT). There were differences between children with spastic CP and children with TD in visual and composite balance score of SOT significantly (p<0.05); there were no differences at vestibular and somatosensory scores of SOT. Children with CP had more postural sway than children with TD (p<0.05). There were differences between children with mild CP and TD in terms of postural control responses.

Balance control impairments in Fabry disease.

BackgroundFabry disease (FD) is a rare inherited lysosomal storage disorder caused by the deficiency of the enzyme alpha-galactosidase A. This deficiency leads to an accumulation of glycosphingolipids leading to progressive and multisystemic disease, including renal, cardiac, and neurological damages. FD may also have neuro-otological and visual impairments, which can generate postural control alterations, inner ear, and vision being involved in this function. This study aimed to evaluate the impact of FD on postural control.MethodsIn total, fourteen adult patients (8 men/6 women, mean age = 37.6 ± 11.4 years) and two children (mean age = 11 years) with FD and 19 healthy adults (12 men/7 women, mean age = 36.5 ± 16.9 years) and two healthy children (mean age = 10.5 years) took part in this study. Postural control was evaluated by a sensory organization test combining three visual situations (eyes open, eyes closed, and sway referenced visual surround motion) with two platform situations (stable platform and sway referenced platform motion), aiming to calculate a composite equilibrium score (CES), a high score being representative of good postural control. Somatosensory (RSOM), visual (RVIS), and vestibular (RVEST) contributions to postural control were calculated, a low score reflecting a poor use of the indicated sensory input.ResultsThe CES was lower in adult patients with FD compared with the healthy subjects (p < 0.001). RVIS (p = 0.001) and RVEST (p = 0.003) were lower in patients with FD compared with the control group, whereas no difference in RSOM was observed.ConclusionInner ear and visual pathologies associated with the central nervous system impairments are factors of postural control impairments. Physical activities, which can also be rehabilitative, by maintaining or increasing the weight of proprioception, may help diminish dependency on altered sensorial inputs.

Impact of Sensory Afferences in Postural Control Quantified by Force Platform: A Protocol for Systematic Review.

Older adults’ postural balance is a critical domain of research as balance deficit is an important risk factor for falls that can lead to severe injuries and death. Considering the effects of ageing on sensory systems, we propose that posturographic evaluation with a force platform exploring the effect of sensory deprivation or perturbation on balance could help understand postural control alterations in the elderly. The aim of the future systematic review and meta-analysis described in this protocol is to explore the capacity of older adults to maintain their balance during sensory perturbations, and compare the effect of perturbation between the sensory channels contributing to balance. Seven databases will be searched for studies evaluating older adults’ balance under various sensory conditions. After evaluating the studies’ risk of bias, results from similar studies (i.e., similar experimental conditions and posturographic markers) will be aggregated. This protocol describes a future review that is expected to provide a better understanding of changes in sensory systems of balance due to ageing, and therefore perspectives on fall assessment, prevention, and rehabilitation.

Does weight loss affect the center of pressure of children with obesity: a follow-up study

BackgroundChildren with obesity were found to show the greater postural instability compared to the normal-weighted children. However, it’s still unclear if their altered postural control ability would recover towards normal pattern after weight loss. The purpose of this study was to investigate the effect of weight loss on the center of pressure (COP) for obese children.MethodTotally 147 children were conducted a follow-up study in three years. A total number of 22 participants aged 7–13 years were recruited for their remission of obesity problem after 36 months. Their dynamic plantar pressure data were collected by Footscan pressure plate. The normalized time of four sub-phases, displacements and velocities of COP in anterior–posterior (AP) and medial–lateral (ML) directions were calculated to perform the Kolmogorov–Smirnov test and paired sample t test for statistical analyses.ResultsAfter weight loss, children’s normalized time of forefoot contact phase (FFCP) increased significantly, and their duration of flat foot phase (FFP) decreased significantly. They also exhibited the more medial and posterior orientated COP path after weight loss. In ML-direction, the COP displacement during FFP and FFPOP increased, and the COP velocity during FFPOP increased. In AP-direction, COP velocity during FFP and FFPOP increased.ConclusionsThe findings indicated that weight loss would have effects on the COP characteristics and postural stability for obese children. COP trajectory can provide essential information for evaluating foot function. The findings may be useful for obese children, medical staff, and healthcare physician.Graphical

Balance control in unstable sitting in individuals with an acute episode of low back pain

BackgroundLow back pain (LBP) is associated with altered postural control, mostly observed at later stages in the LBP trajectory. It is unclear whether postural control differs in the acute phase of LBP. Research questionIs postural control different in the acute phase of LBP (<2 weeks) and do differences depend on pain intensity, psychological features and/or availability of vision to control posture? MethodsCross-sectional study design. An unstable sitting paradigm (to reduce the contribution of the legs) assessed postural control of participants with acute LBP (n = 133) and pain-free controls (n = 74). Centre of pressure (CoP) reflected seat movements. Participants balanced with eyes closed, open, or with visual feedback of the anteroposterior CoP position. Balance performance was expressed by CoP displacement and velocity, and stabilogram diffusion analysis. Generalised estimating equations (GEEs) including body mass index, sex, and safety bar touch, tested differences between groups and between balance conditions. Separate GEEs were used to model performance measures and bar touch (yes/no) including pain intensity, disability and psychological features. ResultsCoP displacement and critical point coordinates (time and distance where CoP diffusion rate or spread slows) were larger in LBP than pain-free controls independent of balance condition. Long-term diffusion rate was greater in LBP than controls with eyes closed. CoP velocity measures (RMS, short term diffusion rate) were not different between groups. Pain intensity and psychological features were not linearly related to balance performance in participants with acute LBP. Higher pain catastrophizing was associated with touching the safety bar. SignificancePostural control differs in acute LBP than pain-free controls. Findings might be explained by altered sensory processing, lesser ability to reweight proprioceptive information and/or less accurate trunk muscle control. Although not linearly related to pain-intensity or psychological features in the acute stage, reduced balance performance could potentially have impact on LBP recovery.

Patients with low back pain use stiffening strategy to compensate for movement control during active prone hip rotation: A cross-sectional study.

New motor adaptation to pain theory suggests that patients with low back pain (LBP) use the lumbopelvic stiffening strategy by redistribution of within and between muscle activities to protect painful structure. This could result in an altered postural control of the lumbopelvic region during active prone hip rotation (PHR). To investigate coordination and timing of lumbopelvic and hip movements, and smoothness of the lumbopelvic control during PHR between participants with and without LBP. Eight participants with LBP and eight participants without LBP were recruited. The electromagnetic tracking system was used to record kinematic data during PHR. Cross-correlation between hip rotation and lumbopelvic movement in the transverse plane was calculated. Correlation at zero time-lag, time-lag, correlation at time-lag, and maximal lumbopelvic motion were derived. Frequency of movement disruption was identified. An independent t-test was used in conjunction with the effect size and 95% minimal detectable difference (MDD95) to determine the difference in kinematic parameters. Participants with LBP demonstrated a significant delay (exceeding MDD95) in lumbopelvic motion while nonsignificant frequency of disrupted motion on the painful side PHR demonstrated a trend with a large effect size that exceeded MDD95. There were trends with moderate to large effect sizes and differences exceeding MDD95 in delay of lumbopelvic motion with greater movement disruption on the nonpainful side in participants with LBP. Participants with LBP used a lumbopelvic stiffening strategy for postural control to protect painful structures; however, the stiffening might complicate efforts to smoothly control lumbopelvic movement.

Falls and motor behavior in older adults

This mini-review focuses on intrinsic risk factors for falls, particularly the changes in motor behavior of faller older adults. Our purpose is to present evidence that faller older adults exhibit motor behavior changes beyond the typically investigated standing and walking tasks. We showed initially that postural control alterations with more prominent differences for fallers than non-fallers seem to depend on postural demands, availability of sensory information, and tasks performed concomitantly with the balancing task. We also provided evidence that walking speed is the most consistent aspect to differentiate fallers from non-fallers. This reduction in walking speed may be a strategy to improve gait stability to avoid a fall. More recent studies have shown that fallers presented modifications in the control of the prehension movement. These changes suggest that fallers have changes in movement categories other than balancing and walking, suggesting that fallers’ difficulties are broader than previously thought. The fact that faller older adults have modifications in the control of upper and lower limbs is indicative of a change in motor behavior involving gross and fine motor behaviors. The understanding of a faller as an individual with global changes in motor behavior has important implications for fall prevention and rehabilitation programs for these individuals.

Disrupted somatosensory input alters postural control strategies during the Star Excursion Balance Test (SEBT) in healthy people.

Chronic adaptations, including persistent sensorimotor deficits, remain in individuals with a history of ankle instability, resulting in altered postural control strategies during functional tasks such as gait, running, or landing. However, we do not know the contribution of the altered somatosensory input on postural control strategies during a dynamic balance task such as the Star Excursion Balance Test (SEBT). The purpose of this study was to characterize postural control strategies with and without disrupted somatosensory input during a dynamic balance task in people without chronic ankle sprain. This study was a crossover study design. Twenty healthy young adults (10 men, 10 women; age = 23.9 ± 3.0 years, height = 174.2 ± 7.4 cm, mass = 71.2 ± 16.7 kg) performed the posteromedial reach test during the SEBT while standing on the ground and on foam. We measured the maximum reach distance (MRD); joint angles of the ankle, knee, hip, and trunk in the sagittal, frontal, and transverse planes; and position and displacement of the center of mass (COM) and center of pressure (COP) during the posteromedial reach task. The MRD was shorter when standing on the foam than on the ground (p < 0.001). There was a condition by phase interaction for ankle dorsiflexion; tibia internal rotation; and trunk flexion (p < 0.001; p = 0.03; p = 0.01, respectively). The COM and COP were positioned more laterally on the foam (p < 0.001). The COM and COP anterior-posterior displacements were more anterior during the foam condition (p = 0.017). By using a foam pad to disrupt somatosensory information, participants demonstrated altered strategies to control the joint kinematics, COM, and COP, as a function of posteromedial distance. Ankle and trunk movement strategies may influence the posteromedial reach distance. This model may simulate changes that occur with chronic ankle instability.

Rating of perceived exertion (RPE) in studies of fatigue-induced postural control alterations in healthy adults: Scoping review of quantitative evidence.

Amongst the literature researching the effects of exercise-induced fatigue on postural control in healthy adults, many studies have used the Borg scales to document the rating of perceived exertion (RPE) and have shown a broad range of RPE values. Our main aim was to map fatigue-induced RPE values in included publications. Secondary aims were to summarize the preference and purpose for the use of Borg scales within the included publications and to explore the potential associations between fatigue-induced RPE values and postural control changes. Five databases (Ovid Medline, PubMed, CINAHL, Scopus, and SPORTDiscus) were systematically searched for synthesizing data among the publications that reported RPE values on the Borg RPE- and Category-Ratio (CR) 10 scales and also found fatigue effects on postural control in healthy adults. Spearman's rank correlations were conducted to assess potential associations between fatigue-induced RPE values and maximal postural control changes across the included publications (group data). 45 of 51 studies included in this review reported maximal RPE values following exercise and ranged from 10.4-20 (6-20 Borg RPE) or 0.9-10 (CR10) indicating "very light" or "very weak" to "maximal" exertions. The 6-20 Borg and CR10 scales were mainly used to assess cardiovascular and muscular exertion, respectively. The scales were used mostly to estimate fatigue levels (n = 45), and to a lesser extent to produce a specific exercise intensity (n = 5) and as the criterion for exercise termination (n = 1). In general, there was no significant association between RPE and postural control changes across studies. The broad range of RPE values and weak correlations may suggest that various fatigue levels can lead to postural control changes. However, one should be careful in comparing the extent of fatigue from RPE values and its potential effect on postural control in the light of many confounding factors.

Concurrent Validity of Inertially Sensed Measures during Voluntary Body Sway in Silence and while Exposed to a Rhythmic Acoustic Stimulus: A Pilot Study

Introduction: The effect of rhythmic acoustic stimuli on body sway is of increasing interest due to their positive contribution when training or restoring the control of movement. Inertial sensors show promise as a portable, easier, and more affordable method compared to the force plate “gold standard” concerning the evaluation of postural sway. This study examined the concurrent validity of inertially sensed measures of voluntary body sway against those obtained with a force plate, in silence and while exposed to a rhythmic acoustic stimulus. Methods: Temporal (sway duration and variability) and spatial (trajectory length, variability, range, velocity, and area) body sway variables were extracted using an inertial sensor (at L5) in synchronization with a force plate, during anteroposterior body sway in silence and while exposed to a rhythmic acoustic stimulus (n = 18 young women; two 70-s trials in each condition). Statistics included bivariate correlations between the inertially sensed and the force plate measures, separately, in silence and with a rhythmic acoustic stimulus, as well as for the effect of the rhythmic acoustic stimulus (percentage difference from silence) (p ≤ 0.05, SPSS v25.0). Results: The inertially sensed measures demonstrated good-to-excellent concurrent validity for all temporal and almost all spatial variables, both in silence and with rhythmic acoustic stimulus (r > 0.75, p = 0.000), as well as for the rhythmic acoustic-stimulus effect (r > 0.75, p ≤ 0.05). Conclusion: The inertially sensed measures of the voluntary anteroposterior body sway demonstrated an overall good-to-excellent concurrent validity against those obtained with the force plate “gold standard,” both in the silence and the rhythmic acoustic stimulus conditions, as well as for the rhythmic acoustic-stimulus effect. The findings of this pilot study allow the recommendation of inertial sensing for the evaluation of postural control alterations when exposed to rhythmic acoustic stimuli, a condition of increasing interest due to the positive contribution of such stimuli when training or restoring the control of movement.

Understanding Postural and Segmental Trunk Control and Their Effect on Sitting in Children with Cerebral Palsy: A Systematic Scoping Review

Cerebral palsy (CP) is a heterogeneous group of neuromuscular disorders with disorganized postural and segmental trunk control that limits functional abilities. Sitting is essential for development but is commonly affected in CP due to poor head and trunk control. This scoping review aims to understand and describe literatures addressing the effect of altered postural and segmental trunk control on sitting in children with CP. A comprehensive systematic search of online databases, research hosting directories identified 1539 studies published from 2010 to 2020 on postural and segmental trunk control and sitting in CP, of which 11 qualitative studies were retrieved. Interventional studies were excluded as the review aimed to understand the dysfunctional mechanisms of control and its effects on sitting abilities, rather than strategies to improve it. The potential risk for bias in selected studies were controlled through clearly described eligibility criteria in study selection, study quality appraisal and randomization during data extraction and synthesis process. The outcomes were categorized into postural control, segmental trunk control, and sitting abilities in children with CP and were analyzed for 481 children across the 11 studies included in this review. It is noted that children with CP present with delay and dysfunction of postural and segmental trunk control, thus leading to reduced variability in acquiring independent sitting to perform various activities. Postural and segmental trunk control are essential to achieve independent sitting and improve functional abilities. However, owing to the neuromuscular deficits, these components are impaired in children with CP and thus hamper functional ability. Therefore, a thorough evaluation of these components is vital and can help estimate the child's functional ability and plan interventional goals accordingly.

Balance Control and Muscles Activity of An Elderly Retired Man During Different Focus of Attention Instructions

Background: Good balance and muscle activity are essential to do daily activities. Recent studies have focused on the relations between balance and attention patterns. The study of the balance and muscle activity of people in different patterns of attention can clarify the nature of the effect of attention instructions. Purpose: The present study aims to evaluate the changes in different focus of attention instructions and quality of balance control and muscle activity in the elderly retired. Methods: Thirty elderly retired men [mean age: 51.6 ± 6.4 years] were recruited for this study. Subjects were selected through the berg balance test. Balance control ability [Biodex Balance System] and muscle activity [electromyography system] were assessed in two conditions, internal attention and external attention task. The data obtained were analyzed using repeated-measures ANOVA at a significant level of P&lt;0.05. Results: Body sway and muscle activity parameters were correlated with different patterns of attention. During external focus condition, [1] Center of Pressure [CoP] total two-leg balance, CoP medio-lateral and CoP anterior-posterior for external-focus were lowered [P&lt;0.05] and [2] Tibialis anterior and soleus for the leg, biceps brachii and triceps brachii for the arm, sternocleidomastoid and semispinalis capitis for external-focus were lowered [P&lt;0.05]. Conclusion: Improved static balance responses and alterations in postural control were observed under external focus conditions. An external focus of attention may be the preferred method for facilitating balance control and muscle activation in an elderly retired man.