Differences In Postural Stability Research Articles

Intersession reliability of center of pressure measurement during bipedal standing with different foot placement angles

IntroductionThe foot placement is a determinant of the base of support and influences standing balance. The reliability of postural stability tests with different foot placement angles is unclear. Research questionTo determine and compare the intra- and inter-day reliability of the center of pressure-based postural stability while standing with different foot placement angles. MethodTwenty-five healthy adults (16 females and 9 males; age: 29 ± 6 years) completed 70 s trials of eyes open and eyes closed stability tests with 0°, 15°, 30°, and 45° angles between the feet while standing on a forceplate in three sessions: two sessions were in the same day, and the third session was one-week apart. The repeatability of measurements was tested using analysis of variance, interclass correlation, and standard error of measurements. ResultThroughout the three study sessions, there was no difference in postural stability while participants stood with different foot placement angles. The interclass correlation scores ranged from 0.71 to 0.96, the standard error of measurements ranged from 2.1% to 12.9%, and no significant systematic changes (p < 0.05) occurred between the testing sessions for any foot placements. Standing with a 45° angle between the feet with closed eyes showed higher reliability values than other conditions. The intra-day reliability scores were greater than inter-day reliability. DiscussionThe relative reliability of postural stability could be impacted by foot placement angles, which might alter ankle mobility and base of support dimensions. The advantages of larger foot placement angles on improving the relative reliability of postural stability could be better demonstrated in healthy people under challenging conditions such as standing with closed eyes. ConclusionStanding with foot placement angles between 0° and 45° are reliable and a quantitative assessment of the center of pressure could be used to monitor the changes in postural stability between sessions.

Postural stability of adults with down syndrome – differences between women and men

ObjectiveThis study aimed to analyse differences in postural stability (PS) between adults with Down syndrome (DS) and adults without DS of the same age and to compare the PS between men and women with DS.MethodsTwenty-six individuals with DS (mean age 38.4 ± 8.7 yrs.) and 26 individuals without DS (mean age 38.8 ± 9.2 yrs.) participated in the study. Postural stability was measured using a pressure sensing platform MobileMat 3140 (Tekscan) in these modifications of the bipedal stance: a. wide base of support with the eyes open (WO); b. wide base of support with the eyes closed (WC); c. narrow base of support with the eyes open (NO). Six parameters of PS were compared in the statistical analysis: centre of pressure (COP) path length, COP excursion front-back, COP excursion left-right, COP velocity average, time to boundary (TTB) front-back, and TTB left-right.ResultsMost PS variables (COP path length, COP excursion left-right, COP velocity average, TTB front-back) indicate significantly lower PS of adults with DS than that of the reference group (p < 0.05). Some PS variables (COP path length and COP velocity average in WC, COP excursion front-back and COP excursion left-right in NO) showed differences between men and women in more demanding conditions, indicating lower PS in men with DS.

Age-related differences in the capacity and neuromuscular control of the foot core system during quiet standing.

The foot core system is essential for upright stability. However, aging-induced changes in the foot core function remain poorly understood. The present study aimed to examine age-related differences in postural stability from the perspective of foot core capacity and neuromuscular control during quiet standing. Thirty-six older and 25 young adults completed foot core capacity tests including toe flexion strength, muscle ultrasonography, and plantar cutaneous sensitivity. The center of pressure (COP) and electromyography (EMG) of abductor hallucis (ABH), peroneus longus (PL), tibialis anterior (TA) and medial gastrocnemius (GM) were simultaneously recorded during double-leg and single-leg standing (SLS). EMG data were used to calculate muscle synergy and intermuscular coherence across three frequency bands. Compared to young adults, older adults exhibited thinner hallucis flexors, weaker toe strength, and lower plantar cutaneous sensitivity. The ABH thickness and plantar cutaneous sensitivity were negatively associated with the COP mean peak velocity in older adults, but not in young adults. Besides, older adults had higher cocontraction of muscles spanning the arch (ABH-PL) and ankle (TA-GM), and had lower beta- and gamma-band coherence of the ABH-PL and TA-PL during SLS. Foot core capacities became compromised with advancing age, and the balance control of older adults was susceptible to foot core than young adults in balance tasks. To compensate for the weakened foot core, older adults may adopt arch and ankle stiffening strategies via increasing muscle cocontraction. Furthermore, coherence analysis indicated that aging may increase the demand for cortical brain resources during SLS.

Dynamic postural control in injured collegiate cross-country runners is not associated with running-related injury

BackgroundBiomechanical factors have been associated with running-related injury, but associations are unclear. Dynamic postural stability may be a factor related to injury that has not been studied extensively. Research questionDoes dynamic postural control differ in those with a history of running-related injury or those who go on to sustain a running-related injury? MethodsSixty-five (45 injured; 20 uninjured) and fifty-eight (13 injured; 45 uninjured) collegiate cross-country runners were available for our retrospective and prospective analyses. Time to stabilization and dynamic postural stability index were collected during two separate jump landing tasks (forward and lateral direction) for each leg. Retrospective injury was tabulated by a running history survey. Prospective injuries were recorded by a licensed athletic trainer during the competitive season. Differences in postural stability were compared between injured and uninjured groups and between limbs using two-way ANOVA’s. An overall group by leg comparison was completed for each task. ResultsThe non-dominant limb demonstrated better postural stability indices regardless of injury history. An interaction was observed between limbs and history of injury for the anterior-posterior time to stabilization for the lateral task. The non-dominant limb demonstrated better medio-lateral postural stability indices and time to stabilization during the lateral task, regardless of prospective injury. SignificanceDynamic postural stability was reduced in the dominant limb, but no clear differences were seen between injured and uninjured runners. This suggests dynamic postural stability may be altered in individuals with a history of a running-related injury, but no relationship to subsequent injury was substantiated. Further work is needed to understand how dynamic postural stability may be related to running-related injury.

Geschlechtsspezifische Unterschiede in der ­posturalen Stabilität? Analyse mit dem Posturomed®

Postural stability is critical for injury prevention and rehabilitation. An advantage in favor of female subjects compared to males could be determined in many studies, whereby the quantification, reliability and validity are limited due to the method. The Posturomed® allows to measure stability in the vertical and horizontal directions. So far, there are no studies that have recorded postural stability with the Posturomed® and examined gender-specific differences. Hypothesis: The measured values show gender-specific differences in favor of female subjects. Study design: Prospective, exploratory study. Material and Methods: In our study, 100 subjects were tested on the Posturomed® using the test procedure specified by the manufacturer. The mean values of both legs were compared for differences depending on gender using the Mann-Whitney U test. Results: The measurements revealed a significant difference in favor of the female subjects with a mean effect size r=0.22 (p&lt;0.05) for right and a mean effect size r=0.24 (p&lt;0.05) for left. Conclusion: In our study female subjects can achieve higher postural stability measurements than male subjects. A mean effect size can be determined here. This is the first study to demonstrate and quantify significant gender differences in postural stability in favor of female subjects.

Gender Differences in Postural Stability in a Cohort of Adolescent Age

Daily tasks necessitate improved locomotive abilities and movements, which are determined by an individual’s balance control. Body postures allows us to stay in a stable and balanced stance without falling. The present study examines postural stability in males and females using centre of pressure metrics in two planes for the adolescent group. Force data was collected in three directions (Fx, Fy, and Fz) using a standard force platform (SENSIX force plates) under two support and two visual conditions, including eyes-open, stand-up on two limbs (OB), eyes-closed, stand-up on two limbs (CB), eyes-open, stand-up on single limb (OO), eyes-closed, stand-up on single limb (CO). The CoP was determined in both the antero-posterior and medio-lateral planes. Two features were derived from the CoP data: sway and average velocity in both planes. The findings demonstrate that for all experimental conditions in both directions, CoP characteristics (sway and velocity) of male gender were significantly (p<0.05) higher than female gender. This work concludes that males have higher postural stability than females of similar age, indicating that hormonal variables such as thyroid, estrogens, and others reduce postural stability.

Difference in postural stability between STarT Back Tool subgroups of patients with low back pain under conditions of sensory deprivation and cognitive load.

ObjectiveWe explored differences in postural stability between subgroups of patients with low back pain (LBP) and varying risk levels for developing chronicity measured using the Subgroups for Targeted Treatment (STarT) Back Tool.MethodsThis was a cross-sectional, single-session, double-blind experimental study among 65 participants who had LBP for more than 14 days. Postural stability was assessed by measuring the center of pressure (COP) range, displacement area, and velocity in anterior–posterior and mediolateral directions under four sensory and cognitive conditions: (i) eyes open and counting forward, (ii) eyes closed and counting forward, (iii) eyes closed and counting forward in multiples of seven, and (iv) eyes closed and counting backward in multiples of seven. The participants were stratified into low-/medium- (n = 53) and high-risk (n = 9) subgroups.ResultsThere were no significant between-group differences among patients with LBP stratified as having a low/medium or high risk of chronicity in postural stability and sensory and cognitive conditions.ConclusionsImpaired postural stability is important to consider when treating patients with LBP. However, we found that these impairments were not strongly aggravated in groups with a higher risk of chronicity, as measured using the STarT Back Tool.

Dizziness Is Associated With Neck/Shoulder Pain Following Pediatric Concussion.

To examine the association between dizziness and neck/shoulder pain after concussion and if differences in postural stability and oculomotor function exist among patients reporting dizziness with or without concurrent neck/shoulder pain. Cross sectional. Sports medicine clinic. Pediatric patients ≤14 days post concussion. N/A. Patients completed the Health and Behavior Inventory (HBI) symptom rating and separately rated neck/shoulder pain (scale 0-3; 0 = no pain). We grouped patients by HBI dizziness rating (0 = not-dizzy; 1-3 = dizzy) and compared neck/shoulder pain ratings between the groups. We then compared oculomotor and postural stability outcomes between dizzy patients with and without neck/shoulder pain. We included 153 patients: dizzy (n = 100; age = 14.6 ± 2.2 years; 48% female) and not-dizzy (n = 53, age = 14.4 ± 3.1 years; 38% female). The dizzy group reported significantly higher neck/shoulder pain (1.4 ± 1.1 vs 0.5 ± 0.9 points, P < 0.001) and total symptom score (25.7 ± 11.2 vs 11.7 ± 9.3 points, P < 0.001) than the not-dizzy group. After adjusting for total symptom score and preinjury anxiety, depression, and migraines, dizziness was associated with higher odds of neck/shoulder pain (odds ratio = 1.9, 95% CI, 1.2-3.0; P = 0.004). No differences were observed between dizzy patients with and without neck/shoulder pain for near point of convergence (10.0 ± 7.5 vs 8.5 ± 6.7 cm, P = 0.43), modified Balance Error Scoring System (8.9 ± 5.5 vs 6.8 ± 4.7 errors, P = 0.09), or tandem gait (single-task: 26.0 ± 12.3 vs 24.2 ± 11.9 seconds, P = 0.56; dual-task: 35.1 ± 14.3 vs 35.6 ± 18.6 seconds, P = 0.90). In concussion patients experiencing dizziness, evaluating neck/shoulder pain may help identify individuals who would benefit from cervical spine rehabilitation. However, other potential causes of dizziness should also be evaluated to facilitate timely recovery.

Effects of Pre-Collegiate Sport Specialization on Cognitive, Postural, and Psychological Functions: Findings from the NCAA-DoD CARE Consortium.

Background: Early sport specialization has been associated with an increased risk of musculoskeletal injuries and unfavorable psychological outcomes; however, it is unknown whether sport specialization is associated with worse cognitive, postural, and psychological functions in first-year collegiate student-athletes. Methods: First-year collegiate multisport (MA) and single-sport (SA) student-athletes were identified using a pre-collegiate sport experience questionnaire. The cognitive, postural, and psychological functions were assessed by the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and Brief Symptom Inventory 18 (BSI-18). Results: MA student-athletes performed higher in cognitive outcomes (e.g., higher ImPACT visual memory composite scores [ß = 0.056, p < 0.001]), but had higher psychological distress (e.g., higher BSI-18 global severity index [ß = 0.057, p < 0.001]) and no difference in postural stability (p > 0.05) than SA student-athletes. Conclusions: This study indicated first-year collegiate athletes with a history of sport specialization demonstrate lower cognitive performance but decreased psychological distress and no differences in static postural stability as compared to their MA counterparts. Future studies should consider involving different health measures to better understand the influence of sport specialization on overall physical and mental health.

Postural Stability in Single-Leg Quiet Stance in Highly Trained Athletes: Sex and Sport Differences.

This study aimed to determine if there is a difference in postural stability in highly trained adolescents and young adult athletes regarding sex and sport. The participants were young athletes (n = 464) from seven different sports. We considered the center of pressure (CoP) velocity (total, anterior–posterior (AP) and medial–lateral (ML)), CoP amplitude (AP and ML), and CoP frequency (AP and ML), as assessed by single-leg quiet stance test. Significant interactions were found between sex and sport for all CoP variables (p < 0.02). Additionally, a significant main effect of sport was also found in all CoP variables (p = 0.01). Regarding sex, significant effects were found for all CoP amplitude variables (p = 0.01), as well as for CoP velocity variables, except for CoP ML (p = 0.06). Moreover, there was no sex effect for CoP frequency AP (p = 0.18). The results of the current study confirm the claim that the criteria for optimal postural strategies for elite athletes likely depend on a given sport.

Postural Control and Psychophysical State Following of Flight Simulator Session in Novice Pilots.

Flight simulators can cause side effects usually called simulator sickness. Scientific research proves that postural instability can be an indicator of the occurrence of simulator sickness symptoms. This study aims to assess changes of postural control and psychophysical state in novice pilots following 2-h exposure to simulator conditions. The postural sway was quantified based on variables describing the displacement of the Center of Pressure (COP) generated in a quiet stance with eyes open (EO) and closed (EC). The psychophysical state was assessed using the Simulator Sickness Questionnaire (SSQ). The research was carried out in a group of 24 novice pilots who performed procedural and emergency flight exercises in the simulator at Instrument Meteorological Conditions. Each subject was examined twice: immediately before the simulator session (pre-exposure test), and just after the session (post-exposure test). The differences in postural stability between pre- and post-exposure to simulator conditions were assessed based on the normalized Romberg quotients, calculated for individual variables. The lower median values of all Romberg quotients confirmed the decreasing difference between the measures with eyes open and with eyes closed in the post-exposure tests. After the flight simulator session in both measurements (EO and EC) the values of the length of sway path (SP), the mean amplitude (MA), the sway area (SA) have changed. The visual contribution to postural sway control was reduced. The median values for all SSQ scores (total, nausea, oculomotor, and disorientation scales) were significantly higher in post-exposure tests. The largest increase was noted in the oculomotor SSQ scores (from 7.6 ± 7.6 to 37.9 ± 26.5). Over 50% of pilots participating in this study expressed symptoms typical of simulator sickness connected with visual induction: fatigue, eyestrain, difficulty focusing and difficulty concentrating. The severity of oculomotor and disorientation symptoms were rated as moderate (total SSQ score of more than 25 and <60). This study concludes that changes noted in the postural control and psychophysical state of the studied pilots after exposure to the flight simulator confirm the occurrence of the simulator sickness symptoms. Although, we did not find significant correlation of postural stability with SSQ scores.

Characteristics of postural control during fixed light-touch and interpersonal light-touch contact and the involvement of interpersonal postural coordination.

Haptic feedback by light touch with a fingertip influences the postural control of the human body by postural orientation. Postural control might therefore differ depending on the characteristics of the contacting object. The main experimental targets of contact have been a fixed object (fixed light touch: FLT) and an individual (interpersonal light touch: ILT), but the postural control characteristics of FLT and ILT have not been directly compared within the same study. Nor has there been a study comparing frequency characteristics in these conditions. We hypothesized that (1) the frequency of postural sway would be higher in FLT and that no such change would be observed in ILT, and (2) the interpersonal postural coordination that is specific to ILT, i.e., sway that resembles the other person's sway, would be observed in the low-frequency component (≤0.4 Hz) rather than the high-frequency component (>0.4 Hz). We applied a closed-eyes tandem stance by adult subjects as the standard condition, and the center of pressure was measured when they performed four standing conditions: no-touch, FLT, stable ILT with a bipedal partner, and unstable ILT with a tandem partner. The results demonstrated that the FLT condition and both the stable and unstable ILT conditions also stabilized the posture, but the stability was superior in the FLT condition. Further, the difference in postural stability depending on the axis is not clear in any conditions for velocity, whereas for amplitude, stabilization by contact is more easily captured in the medio-lateral (ML) axis than in the anterior-posterior (AP) axis. The mean power frequency (MPF) in the FLT condition was higher than the no-touch condition, and the stable ILT condition in the ML axis and was higher than any other conditions in the AP axis. Moreover, the stable ILT condition in both axes was not significantly different from the no-touch condition. The unstable ILT condition in the AP axis was also not significantly different, though the ML axis was higher than the no-touch condition. The interpersonal postural coordination in both the stable and unstable ILT conditions was observed in the low-frequency component (except for the ML axis of the unstable ILT condition) and not in the high-frequency component. These results support our hypotheses and suggest that although FLT and ILT exert effects on reducing postural sway to some certain extent, in actuality, these conditions result in different postural controls in the frequency domain due to postural coordination based on the low-frequency component.

Postural stability assessment in flatfoot subjects trough lyapunov exponent analysis

Abstract Background Flatfoot subjects presents an increase plantar foot area related to a plantar pressure feedback impairment. The Lyapunov Exponent is considered a nonlinear parameter used to characterize a signal chaotic behavior measuring the information rate loss from time series, i.e., for the Center of Pressure data. This exponent is used to quantify and measure the capability and resistance of subjects to several perturbations. The study purpose was to investigate the postural stability differences among foot posture condition through the Lyapunov Exponent analysis. Methods The sample of the observation descriptive study consisted of 31 participants (23.26 yo ± 4.43 SD) comprising a total of 62 feet, where 15 integrated into the experimental group with bilateral flatfoot condition and the remaining 16 in the control group with the bilateral neutral foot condition. Subjects were screened, before posture analysis, using the Navicular Drop Test and Resting Calcaneal Stance Position test, to characterize each group. All participants were subjected to a bipedal weight-bearing stance posture stability analysis a force platform, both in eyes-open and closed condition. The Lyapunov Exponent was calculated using the Matlab-R2020b (MathWorks Inc., USA) software. Results Regarding the Center of Pressure outcomes, only the Lyapunov Exponent value upon the Antero-Posterior component regarding groups in the eyes closed condition (diff = 3.09°, p = .016) presented a significant result. Conclusion Flatfoot subjects present a significant difference compared to neutral foot participants, in bipedal weight-bearing stance, in the eyes closed condition regarding the Lyapunov Exponent. This relates to increase variability and decrease stability regarding the Antero-Posterior component.

Quantification of Dual-task Performance in Healthy Young Adults Suitable for Military Use.

Dual-task performance, in which an individual performs two tasks simultaneously, is compromised following mild traumatic brain injury (mTBI). Proficient dual-task performance is essential in a military setting for both military member safety and execution of skilled tasks. To address the unique needs of military members, a portable dual-task assessment was developed incorporating an auditory dual-task task as a novel assessment module utilizing mobile-device technology. The aim of this study was to develop and validate a dual-task mobile device-based application that accurately quantifies cognitive and motor function. Fifty, healthy, military-age civilians completed three cognitive tasks in single- and dual-task conditions with eyes open and closed: visual Stroop, auditory Stroop at 1.5- and 2.5-second stimulus presentation, and number discrimination. All dual-task conditions required the maintenance of postural stability while simultaneously completing a cognitive task. There were no differences between single- and dual-task conditions for cognitive performance on any of the tests, and a ceiling effect was observed for the visual Stroop and auditory Stroop 1.5-second stimulus presentation (P > .05). Significant differences in postural stability were observed between the eyes-open and eyes-closed conditions in all single- and dual-task conditions (P < .01). Significant differences in postural stability were observed between the eyes-open single-task condition and all dual-task conditions (P < .01). Based on the performance of healthy young adults, the number discrimination task may be optimal for detecting subtle changes in dual-task performance. The detected differences found between the eyes-open and eyes-closed conditions provide discriminatory value and insight into the reliance of vision of postural stability performance. While dual-task cognitive performance was not observed in this healthy population, individuals with mTBI may exhibit decreased dual-task performance. The independent evaluation of cognitive and motor function under dual-task conditions has the potential to transform the management and treatment of mTBI.

Evaluation of Postural Stability Differences in the Elderly Through Recurrent Analysis.

Measuring the center of pressure (CoP) for a subject positioned on a force plate is one of the most commonly used tools to investigate balance. Several studies have proven a significant degradation of the body's stability after the age of 60. The conclusions, however, are based on a limited number of indicators and without systematic nonlinear analysis methods being used to evaluate the progression of CoP parameter values. Neither the change in CoP movement in subjects over 60 years of age nor the considerations of their body mass index (BMI) has been systematically evaluated by nonlinear methods so far. This study is based on one of the frequent methods for nonlinear evaluation - the Recurrent Quantification analysis. This article discusses the applicability of this method with regards to the evaluation of changes in postural stability of subjects over 60 years of age. Postural stability changes were evaluated using CoP motion and tested by the nonlinear method. For this research purpose, a group of 103 elderly women were selected and divided into age-respective groups of 60-69 years and 70-79 years old. Each age group was further divided into a subgroup of normal and overweight subjects according to their BMI. The following recurrent analysis parameters were employed in the evaluation of CoP motion in medial-lateral and anterior-posterior directions: determinism (DET), laminarity (LAM) and trapping time (TT). The results of the Wilcoxon test revealed a statistically significant difference between the values in parameters for the different age groups of overweight subjects almost in all the cases. Conversely, statistically significant differences between age groups rarely occurred in a subgroup of subjects with a normal BMI.

Gender Differences in Postural Stability among 13-Year-Old Alpine Skiers.

This experiment examined changes in body sway after Wingate test (WAnT) in 19 adolescents practicing alpine skiing, subjected to the same type of training load for 4–5 years (10 girls and nine boys). The postural examinations were performed with eyes open (EO), eyes closed (EC), and sway reverenced vision (SRV) in the medial-lateral (ML) and anterior-posterior (AP) planes. The displacement of center of foot pressure (CoP), range of sway (RS), mean sway velocity (MV), way length, and surface area were measured in bipedal upright stance before and after the WAnT to assess the influence of fatigue on postural balance. There were no significant differences in WAnT parameters between girls and boys. Relative peak power (RPP), relative total work (RWtot) were (girls vs. boys) 8.89 ± 0.70 vs. 9.57 ± 1.22 W/kg, p < 0.05 and 227.91 ± 14.98 vs. 243.22 ± 30.24 W/kg, p < 0.05 respectively. The fatigue index (FI) was also on similar level in both genders; however, blood lactate concentration (BLa) was significantly higher in boys (10.35 ± 1.16 mM) than in girls (8.67 ± 1.35 mM) p = 0.007. In the EO examination, statistically significant differences between resting and fatigue conditions in the whole group and after the division into girls and boys were found. In fatigue conditions, significant gender differences were noted for measurements in the ML plane (sway path and RS) and RS in the AP plane. Comparison of the three conditions shows differences between EO vs. EC and SRV in AP plane measured parameters, and for RS in ML plane in rest condition in girls. The strong correlations between FI and CoP parameters mainly in ML plane in the whole group for all examination conditions were noted. By genders, mainly RS in ML plane strongly correlates with FI (r > 0.7). No correlation was found between BLa and CoP parameters (p > 0.06). The presented results indicate that subjecting adolescents of both genders to the same training may reduce gender differences in the postural balance ability at rest but not in fatigue conditions and that girls are significantly superior in postural balance in the ML plane than boys. It was also shown that too little or too much information may be destructive to postural balance in young adolescents.

EFFECTS OF BODY SIZE, SHAPE AND COMPOSITION ON THE POSTURAL STABILITY IN THE PRE-PUBERTAL GROWTH SPURT

Children aged 10-11 years are in going through a dynamic developmental period marked by rapid changes in body size, shape, and composition, all of which are sexually dimorphic. The purpose of this study was to analyze the effects of these factors on the postural stability in the pre-pubertal growth spurt. This was a cross-sectional study involving 312 children (152 boys, 160 girls), from 5th and 6th grade (10.8 ± 0.4 years), who were self-assessed as belonging to Tanner stages I and II. Postural balance control was evaluated using the single-legged flamingo balance test. It was observed a significant effect of the ectomorphy, body mass and body height on the postural stability. The variables body fat, endomorphy and mesomorphy did not have statistically significant influence. Additionally, boys and girls aged 10-11 years seem to have similar performance. Determining these anthropometric and morphological parameters effects and gender differences in postural stability is important for many practical fields such as physical education and youth sport.

The Clinical Significance of the Failure to Perceive Vertigo in the Postcaloric Period Despite a Robust Caloric Response.

Purpose The purpose of this project was to explore the association between the perception of motion during caloric testing and two tasks associated with central vestibular processing: postural stability and visuospatial memory. Method This was a prospective study of 25 patients who were found to have nonvestibular etiologies of their symptoms and normal vestibular function test results and who underwent caloric testing with a mean maximum slow phase eye velocity for each irrigation of 15° or greater. Following each caloric irrigation, patients were asked whether they had any sensation of movement. Patients were grouped based on the presence or absence of motion during the caloric exam (motion perception vs. absent perception). Postural stability was assessed using computerized dynamic posturography, and visuospatial memory was assessed using a memory match card game application. Results There were no significant differences between groups on any measures of peripheral vestibular function. However, the Absent Perception Group showed greater postural instability during Condition 5 of posturography and performed significantly worse on a task of visuospatial working memory. Both age and absence of motion perception predicted abnormal performance on measures of postural stability and visuospatial working memory. Conclusions There appears to be clinical implications to a lack of motion perception during the caloric exam in patients with an otherwise normal peripheral vestibular system. Based on the current findings, we are unable to determine whether differences in postural stability and visuospatial memory were due to age or a central vestibular processing deficit.

Compromised Dynamic Postural Stability Under Increased Load Carriage Magnitudes.

Warfighter performance may be compromised through the impact of load carriage on dynamic postural stability. Men and women may experience this impact to differing extents due to postural stability differences. Therefore, the authors investigated the effect of load magnitude on dynamic postural stability in men and women during a landing and stabilization task. Dynamic postural stability of 32 subjects (16 women) was assessed during the unilateral landing of submaximal jumps under 3 load conditions: +0%, +20%, and +30% body weight. Dynamic postural stability was measured using the dynamic postural stability index, which is calculated from ground reaction force data sampled at 1200Hz. Two-way mixed-measures analysis of variance compared dynamic postural stability index scores between sexes and loads. Dynamic postural stability index scores were significantly affected by load (P = .001) but not by sex or by the sex by load interaction (P > .05). Dynamic postural stability index scores increased between the 0% (0.359 ± 0.041), 20% (0.396 ± 0.034), and 30% (0.420 ± 0.028) body weight conditions. Increased load negatively affects dynamic postural stability with similar performance decrements displayed by men and women. Men and women warfighters may experience similar performance decrements under load carriage conditions of similar relative magnitudes.

The differences in postural stability between cross-country and Alpine skiers with intellectual disabilities

The purpose of this study was to analyse differences in postural stability between athletes with ID competing in Alpine and Cross country (XC) skiing to assess the effect of special sports training on postural stability in persons with ID. Athletes with ID were divided into four groups by their discipline: Alpine skiers (n = 9), XC skiers 2.5 to 10 km (n = 10), XC skiers 500 to 1000 m (n = 18) and XC skiers 50 and 100 m (n = 10). All participants were asked to stand barefooted on the Zebris FDM platform (Medical GmbH, Germany) with their eyes open and closed. To compare differences between groups one-way ANOVA with Tukey HSD test was used. To compare the difference between the eyes open and closed, t-test was used. Statistical analysis showed no significant differences between Alpine and XC skiers in analysed variables. The analysis of COP velocity showed superior postural stability in XC skiers 2.5 to 10 km compared to XC skiers 500 and 1000 m. In XC skiers 500 and 1000 m, XC skiers 2.5 to 10 km and Alpine skiers a significant increase in COP velocity was observed when having the eyes closed. In XC skiers 50 and 100 m, no statistically significant differences between the eyes open and closed conditions were observed. Despite different sports training, no difference between Alpine and XC skiers in postural stability was observed. When comparing XC skiers, better postural stability was observed in skiers running longer distances, suggesting that this sports training enhances balance skills needed in everyday life.