Measures Of Postural Stability Research Articles

Evaluation of measurement reliability for selected indices of postural stability based on data from the GYKO Inertial Sensor System.

The main aim of this study is to use comprehensive statistical analyses to evaluate measurement reliability of selected variables that characterize postural stability. The study examined twenty-nine healthy non-athlete students. The examinations were performed twice, with a one-week interval. The Microgate GYKO inertial sensor system was used to evaluate the reliability of variables that characterize postural stability. The relative reliability of the repeated test was evaluated using the intraclass correlation coefficient (ICC) with 95% confidence interval (95% CI). Next, the standard error of measurement (SEM) and minimal detectable change (MDC) were computed. Relative reliability of the repeated test for all analysed variables of ICC ranged from 0.31 to 0.75. For four variables, ICC values were ca. 0.7, i.e., they can be considered as good. For four other variables, ICC ranged from 0.41 to 0.54, with these values considered fair. Satisfactory reproducibility of postural stability measurements using the GYKO inertial sensor system demonstrates that it can offer an inexpensive and efficient alternative to measurements that use force balance platforms.

Is a portable pressure plate an alternative to force plates for measuring postural stability and interlimb coordination of quiet standing balance control?

Center-of-pressure (COP) synchronization and symmetry can inform adaptations in balance control following one-sided sensorimotor impairments (e.g., stroke). As established force plates are impossible to transport, we aimed to criterion validate a portable pressure plate for obtaining reliable COP synchronization and symmetry measures, next to conventional postural stability measures. Twenty healthy adults participated. In a single session, three 40-s eyes-open and eyes-closed quiet stance trials were performed per plate-type, randomly ordered. Individual-limb COPs were measured to calculate between-limb synchronization (BLS) and dynamic control asymmetry (DCA). Net COP (i.e., limbs combined) area, amplitude, and velocity were used to describe anteroposterior (AP) and mediolateral (ML) postural stability. Criterion validity was evaluated using Spearman correlations (r) and Bland-Altman plots. Test-retest reliability was tested using intraclass correlation coefficients (ICC). Strong correlations (r > 0.75) and acceptable reliability (ICC > 0.80) were found regarding individual-limb COP velocity and DCA, net COP ML amplitude and AP and ML velocities. Bland-Altman plots yielded possible proportional bias; the pressure plate systematically underestimated COP scores by force plates and a larger error associated with a larger measurement. Despite correlations between instruments and sufficient reliability for measuring postural stability and DCA, this technical note strongly suggests, due to a systematic deviation, using the same plate-type to accurately assess performance change within subjects longitudinally over time.

Exploring the Nexus of lower extremity proprioception and postural stability in older adults with osteoporosis: a cross-sectional investigation.

Osteoporosis, characterized by reduced bone mass and micro-architectural deterioration, poses a significant public health concern due to increased fracture susceptibility. Beyond bone health, this cross-sectional study aimed to assess and compare lower extremity proprioception and postural stability in individuals with and without osteoporosis and to explore their correlation within the osteoporosis group. In this prospective cross-sectional study, 80 participants were divided into two groups: osteoporosis (n = 40) and control (n = 40). The demographic characteristics and clinical parameters of the participants were as follows: Age (years) - Osteoporosis group: 65.04 ± 4.33, Control group: 65.24 ± 4.63; Sex (%) - Osteoporosis group: Male 30%, Female 70%; Control group: Male 30%, Female 70%; Body mass index (kg/m2) - Osteoporosis group: 23.7 ± 3.2, Control group: 24.5 ± 4.6; T-score (Lumbar) - Osteoporosis group: -2.86 ± 1.23, Control group: 0.27 ± 0.58; T-score (hip) - Osteoporosis group: -2.28 ± 0.79, Control group: 0.68 ± 0.86. Joint Position Sense (JPS) at the hip, knee, and ankle was assessed using a digital inclinometer, and postural stability was measured using computerized force platforms. Osteoporosis participants exhibited higher errors in hip (5.63° vs. 2.36°), knee (4.86° vs. 1.98°), and ankle (4.46° vs. 2.02°) JPS compared to controls. Postural stability measures showed increased anterior-posterior sway (10.86 mm vs. 3.98 mm), medial-lateral sway (8.67 mm vs. 2.89 mm), and ellipse area (966.88 mm2 vs. 446.19 mm2) in osteoporosis participants. Furthermore, correlation analyses within the osteoporosis group unveiled significant positive associations between lower extremity proprioception and postural stability. Specifically, hip JPS exhibited a strong positive correlation with anterior-posterior sway (r = 0.493, p = 0.003), medial-lateral sway (r = 0.485, p = 0.003), and ellipse area (r = 0.496, p < 0.001). Knee JPS displayed a moderate positive correlation with anterior-posterior sway (r = 0.397, p = 0.012), medial-lateral sway (r = 0.337, p = 0.032), and ellipse area (r = 0.378, p < 0.001). Similarly, ankle JPS showed a moderate positive correlation with anterior-posterior sway (r = 0.373, p = 0.023), medial-lateral sway (r = 0.308, p = 0.045), and ellipse area (r = 0.368, p = 0.021). These findings underscore the interplay between proprioceptive deficits, compromised postural stability, and osteoporosis, emphasizing the need for targeted interventions to improve fall prevention strategies and enhance the quality of life for individuals with osteoporosis.

Disability in cerebellar ataxia syndromes is linked to cortical degeneration

ObjectiveWe aimed to relate clinical measures of disability in chronic cerebellar degeneration to structural whole-brain changes using voxel-based and surface-based morphometry (vbm and sbm). We were particularly interested in remote effects of cerebellar degeneration in the cerebral cortex.MethodsWe recruited 30 patients with cerebellar degeneration of different aetiologies (downbeat nystagmus syndrome, DBN n = 14, spinocerebellar ataxia, SCA n = 9, sporadic adult late-onset ataxia, SAOA n = 7). All patients were thoroughly characterised in the motor, cognitive, vestibular and ocular–motor domains. Vbm and sbm were used to evaluate structural differences between cerebellar degeneration patients and a group of healthy age- and gender-matched volunteers. Linear regression models were used to correlate functional measures of disease progression and postural stability with whole brain volumetry.ResultsPatients with SCA and SAOA showed widespread volume loss in the cerebellar hemispheres and less prominently in the vermis. Patients with DBN showed a distinct pattern of grey matter volume (GMV) loss that was restricted to the vestibular and ocular–motor representations in lobules IX, X and V–VII. Falls were associated with brainstem white matter volume. VBM and SBM linear regression models revealed associations between severity of ataxic symptoms, cognitive performance and preferred gait velocity. This included extra-cerebellar (sub-)cortical hubs of the motor and locomotion network (putamen, caudate, thalamus, primary motor cortex, prefrontal cortex) and multisensory areas involved in spatial navigation and cognition.ConclusionFunctional disability in multiple domains was associated with structural changes in the cerebral cortex.

Effects of Foot Structure Type on Core Stability in University Athletes.

This study assessed the impact of different types of medial foot arch on postural stability and core center of gravity muscle activity among collegiate athletes. The study sample included 103 university-level athletes across various sports (soccer, rugby, basketball, volleyball, field tennis, table tennis, karate, and cheerleading) from the College of Magdalena (Colombia) who exhibited distinct types of medial foot arch: 32 high, 35 low, and 36 neutral arches. Surface electromyography (sEMG) was employed to assess conduction velocity, magnitude values, latency, and fatigue in focal muscles including the spinal erector (SE), internal oblique (IO), external oblique (EO), and rectus abdominis (AR), while measurements of static and dynamic postural control were also considered. Post hoc analysis was performed with Bonferroni correction for all electromyographically measured muscle groups, as well as for measurements of static and dynamic postural stability. Pearson's or Spearman's correlation tests were used to compare the different types of feet. There were no substantial differences observed between the distinct types of feet in terms of focal muscle activity, static stability, or dynamics. Even though the mean values indicated higher muscle activity and stability among those with high foot arches and lower values among those with low arches compared to the neutral foot type, this observed difference was deemed statistically insignificant. We also observed a positive correlation between internal oblique muscle activity and the average power of dynamic postural stability, which remained consistent across all foot types. Our findings indicate that static instability is directly correlated with dynamic instability in the anteroposterior direction, while a clear inverse relationship was established in the lateral direction upon examining the variable correlations. The presence of high or low foot arches did not significantly impact the activity of the muscles responsible for maintaining the body's center of gravity or postural stability among university-level athletes. This suggests the existence of neuromuscular compensation mechanisms that attempt to restore balance and compensate for any changes in postural stability caused by varying foot types. Through targeted training that emphasizes activation of the internal oblique muscle, athletes may see improved postural stability. Our findings indicate that static stabilization exercises can also prove beneficial in improving dynamic stability in the anteroposterior plane, while a more dynamic approach may be required to improve dynamic stability in the lateral plane.

Postural stability measures in healthy miniature Dachshunds obtained using a pressure mat and a force platform: a validity and reliability study

BackgroundMiniature Dachshunds have a high prevalence of neurological and musculoskeletal diseases potentially affecting their balance. The postural stability of dogs in quiet standing is an indicator of postural control and can aid in diagnosing and monitoring lameness and other pathologies affecting balance. Measures of centre of pressure (CoP) can be obtained from force and pressure platform systems to evaluate postural stability, however the two systems have not been compared and the latter has not been validated in dogs. The aims of this study were to assess the validity and reliability of using a pressure mat compared to a force platform and report normative values of CoP measures in healthy miniature Dachshunds. Forty two healthy miniature Dachshunds of smooth, long and wire-haired breed types stood still on a pressure mat (Tekscan MatScan®) placed on a force platform and the two systems were synchronised. Maximum anterior-posterior (AP) and medial-lateral (ML) ranges, sway path and 95% area of a best-fit ellipse were computed. Bland-Altman plots and coefficients of correlation assessed validity; intra-class correlation coefficients (ICC) assessed inter-test reliability for both systems. Non-linear regression analyses were used to describe the relationship between CoP and demographic measures.ResultsStrong correlations for AP range, ML range and 95% ellipse area and moderate correlation for sway path were found between the two devices. ICC showed good reliability (0.75–0.90) for AP range and moderate (0.5–0.75) for ML range and the 95% ellipse area for both devices. Sway path reliability was excellent (> 0.90) with the force platform but moderate with the pressure mat. Age was positively correlated with balance (inversely correlated with all measures except sway path), while weight explained 94% (force platform) and 27% (pressure mat) of the variance in sway path.ConclusionsPressure mats can be used to obtain valid and reliable measures of CoP and replace use of force platforms. Older (non-senior) and heavier (non-obese) dogs show better postural stability. Clinical examinations should include the use of a range of CoP measures when assessing postural balance, while accounting for the effects of age and body weight.

Evaluation of the Accuracy of the Postural Stability Measurement with the Y-Balance Test Based on the Levels of the Biomechanical Parameters of 14-Year-Old Girls.

Dynamic balance monitoring involves the assessment of the muscular control during changes of the centre of gravity location in space above the supporting plane. We aimed to determine the structure of the Y-Balance Test and its accuracy based on measurements of strength and resistance to fatigue of muscles acting on the knee joint under static conditions, as well as joint motion ranges and static balance in girls aged 14 years. The study included 40 girls aged 14, who attended Gymnasium No. 2 in Cracow (Poland). The research was conducted in October 2020. Postural stability was examined with the use of the YBT. The measurements of muscle strength and knee joint extensor and flexor resistance to fatigue during an isometric contraction were performed in a standard position on the test bench. The measurements of lower extremity joint range of motion were performed in accordance with the SFTR methodology. Static balance was assessed with the use of the modified FBT. The factor structure obtained for both lower extremities has satisfactorily explained the common variance (about 70%) and showed slight differences between the left and right extremities. The factor structure in the group of examined girls suggests a highly hybrid nature of the Y-Balance Test with a wide spectrum of biomechanical variables that have little influence on the measurement results.

Effects of the Loss of Binocular and Motion Parallax on Static Postural Stability.

Depth information is important for postural stability and is generated by two visual systems: binocular and motion parallax. The effect of each type of parallax on postural stability remains unclear. We investigated the effects of binocular and motion parallax loss on static postural stability using a virtual reality (VR) system with a head-mounted display (HMD). A total of 24 healthy young adults were asked to stand still on a foam surface fixed on a force plate. They wore an HMD and faced a visual background in the VR system under four visual test conditions: normal vision (Control), absence of motion parallax (Non-MP)/binocular parallax (Non-BP), and absence of both motion and binocular parallax (Non-P). The sway area and velocity in the anteroposterior and mediolateral directions of the center-of-pressure displacements were measured. All postural stability measurements were significantly higher under the Non-MP and Non-P conditions than those under the Control and Non-BP conditions, with no significant differences in the postural stability measurements between the Control and Non-BP conditions. In conclusion, motion parallax has a more prominent effect on static postural stability than binocular parallax, which clarifies the underlying mechanisms of postural instability and informs the development of rehabilitation methods for people with visual impairments.

An Absence of Persistent Postural Stability Deficits Following a Sport Concussion in Collegiate Athletes.

The purpose of our study was to determine whether persistent postural stability deficits exist in athletes following sport concussion (SC) in comparison with preinjury (baseline) values using Sample Entropy (SampEn). Sports medicine clinic. Participants consisted of 71 collegiate athletes (44 male, 27 female) with an average age of 19.9 ± 0.96 years who had a history of 1 concussion that occurred during their time as a collegiate athlete. In our prospective, cohort design participants completed the Sensory Organization Test (SOT) at baseline, upon reporting symptom-free following a diagnosed SC, and upon establishing a new baseline prior to the start of the subsequent sport season. The SOT's condition scores were calculated and analyzed in alignment with the manufacturer's instructions. SampEn was calculated in the anterior-posterior (AP) and medial-lateral (ML) directions from the center-of-pressure oscillations over the 20-second time series for each SOT condition. The SOT and SampEn outcome scores for each condition were analyzed with repeated-measures analyses of variance. Significant main effects were observed for the SOT's conditions 3 ( F1.6, 114.8 = 7.83, P = .001, η2 = 0.10 [0.02-0.20]), 5 ( F1.8, 126.8 = 11.53, P < .001, η2 = 0.14 [0.04-0.25]), and 6 ( F1.9, 134.5 = 25.11, P < .001, η2 = 0.26 [0.14-0.37]), with significant improvements across time. Significant main effects were also observed for SampEn in the AP direction for conditions 3 ( F2, 140 = 7.59, P = .001, η2 = 0.10 [0.02-0.19]) and 6 ( F2, 140 = 6.22, P = .003, η2 = 0.08 [0.011-0.170]), with significant improvements across time. Following a diagnosed SC, our results suggest that collegiate athletes returned if not exceeded baseline values at the symptom-free and new baseline assessments. The application of linear and nonlinear measures of postural stability following a SC yielded similar outcomes in conjunction with a baseline assessment. Our findings support the clinical utility of the baseline SC assessment when evaluating persisting balance deficits when using linear or nonlinear measures.

Sleep Problems After Concussion Are Associated With Poor Balance and Persistent Postconcussion Symptoms.

We examined the association of self-reported sleep problems with clinical measures of postural stability, memory performance, symptom burden, and symptom duration following youth concussion. Patients 6-18 years of age presenting ≤21 days postconcussion underwent a clinical evaluation including modified Balance Error Scoring System, single- and dual-task tandem gait, immediate and delayed recall, and symptom severity. We calculated time from injury until symptom resolution and determined the proportion of patients who developed persistent postconcussion symptoms, defined as a symptom duration >28 days postconcussion. We grouped patients based on whether they reported sleep problems at their postconcussion clinical evaluation and compared symptom-based and functional outcomes between groups. Of the 207 patients included, n = 97 (14.3 ± 2.9 years; 49% female; initial visit 10.2 ± 5.8 days postconcussion) reported sleep problems postconcussion and n = 110 (14.3 ± 2.4 years; 46% female; initial visit 9.3 ± 5.4 days postinjury) did not. Those reporting sleep problems postconcussion had significantly more modified Balance Error Scoring System errors than those without (8.4 ± 5.5 vs 6.7 ± 4.7; P = .01), but similar tandem gait and memory performance. A significantly greater proportion of those who reported sleep problems postconcussion experienced persistent postconcussion symptoms than those who did not (53% vs 31%; P = .004). After adjusting for time from concussion to clinical visit and preconcussion sleep problems, postconcussion sleep problems were associated with a 2 times greater odds of developing persistent postconcussion symptoms (adjusted odds ratio = 2.02, 95% CI = 1.01, 4.06; P = .049). Identifying sleep problems early following concussion may allow clinicians to implement targeted treatment recommendations to improve sleep and provide an optimal recovery environment.

Durable improvement in participant-reported measures of disability and objective posturography after computerized vestibular retraining.

Unilateral vestibular deficits are associated with postural instability and loss of quality of life. Common treatments frequently fail to achieve satisfactory outcomes. To assess the durability of changes in participant-reported disability and objective posturography after computerized vestibular retraining. This was a single-group study. Individuals with persistent symptoms of an objectively determined unilateral vestibular deficit completed questionnaires and posturography assessments before and after twelve sessions of computerized retraining, and 4-6 months and 10-12 months after treatment. 13 participants completed the post-treatment assessments; 9 completed the follow up. Mean improvements in perceived disability at 4-6 months after retraining were: DHI 14.3 points (95% confidence interval 4.0 to 24.5), ABC scale 14.9 points (4.3 to 25.6), FES-I 11.6 points (-3.2 to 26.5).The SOT composite score increased by 11.4 points (95% CI 1.9 to 20.9; p = 0.0175) immediately after treatment, 8.9 points (-2.9 to 20.7; p = 0.1528) at 4-6 months, and 10.6 points (2.2 to 19.0; p = 0.0162) after 10-12 months. At the 10-12 month time point, the areas of the functional stability region increased significantly for both endpoint excursion (p = 0.0086) and maximum excursion (p = 0.0025). Computerized vestibular retraining was associated with improved participant reported disability and objective measures of postural stability.

Balancing new technology: Virtual reality for balance measurement case report.

Falling and the inability to maintain balance are the second leading cause of unintentional injury deaths globally. There are a number of chronic and acute conditions characterized by balance difficulties, including neurological diseases, and sport injuries. Therefore, methods to monitor and quantify balance are critical for clinical decision-making regarding risk management and balance rehabilitation. New advances in virtual reality (VR) technology has identified VR as a novel therapeutic platform. VRSway is a VR application that uses sensors attached to a virtual reality headset, and handheld remote controllers for measurement and analysis of postural stability by measuring changes in spatial location relative to the center of mass and calculates various postural stability indexes. This case report evaluates balance measures in 2 healthy participants with no previous history of balance disorders using the VRSway software application and compares to output generated by the current gold standard of balance measurement, force platform technology. The primary objective of this case study was to validate the VRSway stability score for evaluation of balance. Here, we present posturography measures of the VRSway in comparison with force plate readouts in 2 healthy participants. Body Sway measurements were recorded simultaneously in both the force plate and VRSway systems. Data calculated by proprietary software is highly correlative to the data generated by force plates for each of the following measurements for participant-1 and participant-2, respectively: Sway index (r1 = 0.985, P < .001; r2 = 0.970, P < .001), total displacement (r1 = 0.982, P < .001; r2 = 0.935, P < .001), center of pressure mean velocity (r1 = 0.982, P < .001; r2 = 0.935, P < .001), ellipse radius 1 (r1 = 0.979, P < .001; r2 = 0.965, P < .001), ellipse radius 2 (r1 = 0.982, P < .001; r2 = 0.969, P < .001), and ellipse area (r1 = 0.983, P < .001; r2 = 0.969, P < .001). Data from this case study suggest that VRSway measurements are highly correlated with output from force plate technology posing that VRSway is a novel approach to evaluate balance measures with VR. More research is required to understand possible uses of VR-based use for balance measurement in a larger and more diverse cohort.

The relationship of three-dimensional foot morphology to clinical assessments and postural stability in adolescent male footballers

BackgroundFoot morphology is associated with altered loading of the ankle–foot complex in adolescent footballers, predisposing to pain and injury. However, usual singular plane clinical assessments do not accurately capture the 3D nature of foot morphology. A new approach is 3D laser scanning, with statistical shape model techniques creating individual-to-group comparison. However, no research exists on the adolescent, football-playing foot. Furthermore, a link between 3D foot morphology, and usual clinical and performance measures would be beneficial for practical implementation.MethodsFour hundred forty-seven 3D foot scans from 224 elite male footballers (U12-U19) in bilateral stance were collected and further processed with statistical shape model techniques. Weighted shape parameters for individual principal components (Modes) were extracted for each foot. Centre of pressure displacement expressed as total travelled way in millimetres was calculated for bilateral and unilateral postural stability measures. Clinical assessments (Clarke’s Angle, Resting Calcaneal Stance Position) were calculated on the 3D foot scans. Differences in weighted shape parameters, postural stability measures, and clinical assessments between age groups were determined by ANOVA. Correlations determined the relationship of Modes and clinical assessments to postural stability measures. Linear regression established if clinical assessments predicted the mode describing foot arch variation.ResultsAge groups significantly differed for Mode 1 (foot length), Mode 2 (foot arch), and Mode 5 (tibial rotation relative to the foot) (p < 0.05). Resting Calcaneal Stance Position (r = .663) and Clarke’s Angle (r = -.445) were low-to-moderately correlated to Mode 2 (both p < 0.001), and linear regression found they were both significant predictors of Mode 2, though only moderately (R2 = .522). There were low correlations of foot morphology to the postural stability tests.ConclusionThis is the first study to describe the 3D foot morphology of male football-playing adolescents, and discover the differences between age groups. This will improve understanding and assessment of foot morphology in male adolescents because 2D techniques, as discovered in this study, do not strongly correlate to, nor predict, the 3D foot arch. Foot morphology was only lowly correlated to postural stability, thus a multifaceted program would be required for improvements.

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.

Smartphone-based gait and balance accelerometry is sensitive to age and correlates with clinical and kinematic data

BackgroundThe Gait&Balance (G&B) App has produced valid and reliable measures of gait and balance in young healthy adults but has not been tested in older adults. Research questionIn healthy middle-to-older aged adults, are G&B App measurements sensitive to age, valid against clinical and kinematic measures, and reliable? MethodHealthy participants (n = 34, 14 male, 42–94 years) completed the G&B App protocol three times within a single session. 3D kinematics were collected concurrently. Clinical balance measures were collected (Modified Clinical Test of Sensory Interaction in Balance (mCTSIB), Mini Balance Evaluation Systems Test (MBT), and Functional Gait Assessment (FGA)). Sensitivity to age was assessed with Pearson’s correlations. Validity tests included Pearson’s correlations and Bland-Altman limits of agreement. Reliability tests included intra-class correlation coefficients and standard error of the measure. ResultsDuring quiet stance on a compliant surface, the G&B App was sensitive to age-related differences not detectable with the mCTSIB. During walking tasks, there was adequate convergent validity between the MBT and G&B App measures of step length, and between the FGA and G&B App measures of walking speed, step length, and periodicity. The G&B App had moderate-to-excellent validity against 3D kinematics for postural stability during quiet stance (r 0.98 [0.98, 0.99]), step time (r 0.97 [0.96, 0.98]), walking speed (r 0.79 [0.7, 0.86]), and step length (r 0.73 [0.61, 0.81]). Test-retest reliability was moderate-to-excellent for G&B App measures of postural stability, walking speed, periodicity, step length, and step time. G&B App measures of step length asymmetry, step length variability, step time asymmetry, and step time variability had poor validity and reliability. SignificanceThe G&B App was sensitive to age-related differences in balance not detectable with clinical measurement. It provides valid and reliable measures of postural stability, step length, step time, and periodicity, which are not currently available in standard practice.

Effects of odors on posture

AbstractEvidence suggests that postural stability may benefit from olfactory exposure, but whether this effect is different for hyposmic and healthy subjects remains unknown and little attention has been paid to the hedonic valence of odors in this context. Forty‐five participants aged between 23 and 64 years were invited to this study, of whom 32 had normal olfactory function 13 exhibited olfactory deficits. Movement measurements were performed with the “Unterberger stepping test.” Participants walked in place with stretched arms for 8 periods of 30 s each, separated by intervals of approximately 15 s. During each of these 30‐s blocks one of the three odor conditions was presented to them: (a) pleasant odor, (b) unpleasant odor, and (c) odorless control. Both participants with normosmia and impaired olfaction moved to the left and right sides more when exposed to the unpleasant odor as compared to pleasant odor exposure or no odor. When smelling pleasant odors, participants presented shorter maximal anterior/posterior sway than during no odor exposure, but it was similar when smelling unpleasant odor. The study demonstrated strong effects of odors on postural stability with pleasant odors limiting and unpleasant enhancing postural sways.Practical ApplicationsOdors affect postural stability. Although we fail to demonstrate that postural stability measurements can be applied as a supporting method in smell dysfunction diagnosis, the current study opens prospects for further explorations of the relationship between olfactory and vestibular systems. These efforts may eventually lead to practical solutions supporting postural balance in patients suffering from conditions adversely affecting the vestibular system.

Functional Movement Assessments To Evaluate Dynamic Postural Control In Persons With Chronic Ankle Instability

More than 700,000 people sprain their ankles daily, with chronic ankle instability (CAI) occurring in as many as 70% of these individuals. Few research studies have examined the relationship between Functional Movement Screen™ (FMS) and dynamic postural stability in persons with CAI. PURPOSE: To identify differences among measures of dynamic postural stability, FMS-lower extremity scores, and active range of motion (AROM) in those with and without CAI. A secondary purpose was to identify risk factors that predispose individuals to CAI. METHODS: 23 volunteers (12 women, 11 men; age, 22.3 + 2.1 yrs) completed all aspects of this study. We subsequently created 7 triads using a 2:1 ratio, triple matching participants without a history of ankle injury on sex, age, and BMI category with those with CAI. Outcome measures included FMS™ composite score (FMS-CS); FMS™ lower extremity subscore (FMS-LE); Athlete Single Leg Stability Test (ASLST); dorsiflexion, plantar flexion, inversion, and eversion AROM; and Foot and Ankle Disability Index-Sport (FADI-S) score. We used 1-way and 2-way ANOVAs to identify differences between the CASE and CONTROL groups, and the involved and uninvolved limbs of the participants with CAI (p < 0.05). We used binary logistic regression to calculate odds ratios to determine the extent postulated risk factors increased the risk of developing CAI. RESULTS: ANOVA results indicated the CASE group scored significantly lower on the FADI-S (26.7 + 4.1 points) than the CONTROL group (31.0 + 2.7 points) [p = 0.006]. The CASE group had significantly worse (higher) ASLST scores (1.58 + 0.35 degrees) compared to CONTROLS (1.05 + 0.35 degrees) [p = 0.045]. Binary logistic regression analyses indicated that for every 1-point decrease in FADI-S score, the odds of being diagnosed with CAI increased by a factor of 1.5 (p = 0.042). Conversely, for every 1-point increase in Overall Stability Index scores from the ASLST, the odds of being diagnosed with CAI increased by a factor of 0.03 (p = 0.045). CONCLUSIONS: The ASLST scores and FADI-S were significantly worse in the injured ankle of the CASE group compared to their contralateral normal ankle, and the matched ankles from the CONTROL group. A lower FADI-S and a higher ASLST score can be utilized to classify individuals as being more at risk for developing CAI.

Dynamic Postural Stability Is Decreased During the Single-Leg Drop Landing Task in Male Collegiate Soccer Players With Chronic Ankle Instability.

Background:Chronic ankle instability (CAI) is commonly encountered in soccer players. The feelings of instability and anxiety caused by CAI can lead to poor performance, such as difficulty in sharp change of direction during soccer play. The single-leg drop landing (SLDL) task is often used to evaluate dynamic postural stability.Purpose/Hypothesis:The purpose of this study was to clarify whether dynamic stability measured during SLDL is altered in male collegiate soccer players with CAI. The hypothesis was that athletes with CAI would show poor dynamic postural stability.Study Design:Controlled laboratory study.Methods:A total of 103 male collegiate soccer players were recruited, and their limbs were classified based on the new international CAI criteria. All players performed three 5-second SLDL trials on a force plate. The main outcome measures included time to stabilization of the horizontal ground-reaction force (GRF); peak GRF in the vertical, horizontal, and sagittal directions; and trajectory length of the center of pressure during SLDL.Results:Data from 59 CAI limbs and 147 non-CAI limbs were collected in this study. Time to stabilization of horizontal GRF was significantly longer in the CAI limbs (P < .001), and the peak GRFs in all directions were significantly lower in the CAI limbs (vertical, P < .001; horizontal, P < .001; sagittal, P = .001). Additionally, the trajectory length of the center of pressure was significantly greater in the CAI limbs (P = .004).Conclusion:Soccer players with CAI had decreased dynamic postural stability that led them to land softly when performing the SLDL task. Measurement of dynamic postural stability may be useful in the evaluation of CAI.Clinical Relevance:Our findings may be useful for strategies of daily training or as an evaluation tool.

Development of Data-Driven Metrics for Balance Impairment and Fall Risk Assessment in Older Adults.

Ageing incurs a natural decline of postural control which has been linked to an increased risk of falling. Accurate balance assessment is important in identifying postural instability and informing targeted interventions to prevent falls in older adults. Inertial sensor (IMU) technology offers a low-cost means for objective quantification of human movement. This paper describes two studies carried out to advance the use of IMU-based balance assessments in older adults. Study 1 (N = 39) presents the development of two new IMU-derived balance measures. Study 2 (N = 248) reports a reliability analysis of IMU postural stability measures and validates the novel balance measures through comparison with clinical scales. We also report a statistical fall risk estimation algorithm based on IMU data captured during static balance assessments alongside a method of improving this fall risk estimate by incorporating standard clinical fall risk factor data. Results suggest that both new balance measures are sensitive to balance deficits captured by the Berg Balance Scale (BBS) and Timed Up and Go test. Results obtained from the fall risk classifier models suggest they are more accurate (67.9%) at estimating fall risk status than a model based on BBS (59.2%). While the accuracies of the reported models are lower than others reported in the literature, the simplicity of the assessment makes it a potentially useful screening tool for balance impairments and falls risk. The algorithms presented in this paper may be suitable for implementation on a smartphone and could facilitate unsupervised assessment in the home.

The Relationship Between Human-rated Errors and Tablet-based Postural Sway During the Balance Error Scoring System in Military Cadets.

The Balance Error Scoring System (BESS) is commonly accepted as a valid measure of postural stability. However, reliability values have varied, and subtle changes undetectable with the human eye may exist postinjury. The inertial measurement unit in commercially available tablets has been used to quantify postural sway (instrumented Balance Error Scoring System [iBESS] volume). However, iBESS has not been validated in a military population, and the stability of the tests beyond 1 week is unknown. iBESS volume is capable of objectively measuring postural sway during the traditional BESS. Prospective repeated-measures study. Level 3. Eighty-three cadets (40.96% women; age 20.0 ± 1.44 years; height 68.7 ± 4.1 inches; weight 166.7 ± 30.2 lb) with no history of concussion or lower extremity injury agreed to participate. All participants completed the BESS at baseline and 6 months post baseline. During testing, a tablet equipped with an inertial measurement unit was positioned on the participant's sacrum to capture postural sway. Moderate to strong correlations were exhibited between baseline measurements for single-limb (SL)-firm (r = 0.84; P < 0.01), tandem (TAN)-firm (r = 0.85; P < 0.01), double-limb (DL)-foam (r = 0.50; P < 0.01), SL-foam (r = 0.59; P < 0.01), and TAN-foam (r = 0.79; P < 0.01). Balance improved significantly at 6 months for SL-firm human-rated errors (Effect Size [ES] = 0.32) and for SL-firm (ES = 0.38), DL-foam (ES = 0.21), and SL-foam iBESS volume (ES = 0.35). Moderate to strong correlations were exhibited between human-rated and iBESS change scores for SL-firm (r = 0.71; P < 0.01), TAN-firm (r = 0.75; P < 0.01), and TAN-foam (r = 0.71; P < 0.01), and a weak correlation was exhibited for DL-foam (r = 0.29; P < 0.01) and SL-foam (r = 0.40; P < 0.01). Moderate to strong correlations existed between human-rated BESS errors and iBESS volume at baseline and between change scores. In addition, iBESS volume may be more sensitive to balance changes than the human-rated BESS. This evidence supports the use of iBESS volume as a valid measure of postural stability in military cadets. iBESS volume may provide clinicians with an objective and more sensitive measure of postural stability than the traditional human-rated BESS.