Unilateral Stance Research Articles

Dynamics of postural control in individuals with ankle instability: Effect of visual input and orthotic use

The present study investigated the effect of visual deprivation and the use of an ankle orthosis on the dynamics of center of pressure (COP) trajectories during unilateral stance in individuals with ankle instability (AI). Sixteen individuals with AI and nine healthy individuals performed four trials of 30s unilateral stance on a force platform with 1) eyes open wearing no orthosis, 2) eyes closed wearing no orthosis, 3) eyes open wearing orthosis, and 4) eyes closed wearing orthosis. The anterior-posterior and mediolateral COP trajectory were extracted. Regularity was quantified by sample entropy, dimensionality was quantified by correlation dimension and level of time dependency was quantified by entropic half-life. The AI individuals had lower sample entropy and longer entropic half-life in their COP trajectories. The effect of visual deprivation did not differ between groups. Wearing an ankle orthosis increased the sample entropy in the anterior-posterior direction and decreased the correlation dimension in the mediolateral direction for the AI group only. Individuals with AI have higher COP trajectory regularity and higher level of time dependency compared to healthy individuals. Additionally, individuals with AI do not alter the dynamics of their postural control during unilateral stance with visual deprivation compared to healthy individuals. This suggests that alterations in visual or somatosensory information differently affect the executed postural movement pattern. Finally, wearing an orthosis significantly alters the COP dynamics of individuals with AI.

Patellar tendon ultrasonographic properties and lower limb function in rheumatoid arthritis patients

Aim of workThe aim of this work was to investigate patellar tendon (PT) biomechanical properties in rheumatoid arthritis (RA) patients through changes in ultrasonographic tendon properties and its effect on lower limb function.Patients and methodsForty RA patients and 20 healthy participants were included in this study. The physical function was assessed by Health Assessment Questionnaire, the activity of RA by disease activity score 28 and range of motion for all knees by a manual goniometer. RA patients were divided into the following groups: group I comprised patients with low disease activity score 28, who were further subdivided according to the presence of knee flexion deformity into two subgroups (GIA and GIB) and group II patients in the remission stage. Ultrasonography was used for measuring PT elongation and cross-sectional area and quadriceps’ muscle strength was measured. The lower limb function was assessed clinically by 50-foot walk test and smart balance master system through unilateral stance test, step up and over and sit to stand tests.ResultsThere was an increased elongation of PT of all RA groups relative to the control group (P=0.001); no significant difference was found in the PT (cross-sectional area). RA patients showed quadriceps’ muscle strength reduction (P=0.001) and delayed walking time of the 50-foot walk test (P=0.05). Unilateral stance test showed increased center of gravity sway velocity during either eye open or eye closed conditions in RA groups and deterioration in all parameters of step up and over and sit to stand tests (P=0.05–0.001). All physical function evaluation of RA patients showed impairment associated with a reduction of PT stiffness and quadriceps’ strength.ConclusionInflammation of the PT and peritendinous tissues in RA alters its biomechanical properties; this impairs RA patients’ physical and lower limb functions.

Influence of Sacroiliac Bracing on Muscle Activation Strategies During 2 Functional Tasks in Standing-Tolerant and Standing-Intolerant Individuals.

People who develop low back pain during standing (standing-intolerant) are a subclinical group at risk for clinical low back pain. Standing-intolerant individuals respond favorably to stabilization exercise and may be similar to people with sacroiliac joint dysfunction that respond to stabilization approaches including sacroiliac joint (SIJ) bracing. The purpose was to characterize muscle activation and response to SIJ bracing in standing-tolerant and standing-intolerant individuals during forward flexion and unilateral stance. Trunk and hip electromyography data were collected from 31 participants (17 standing-tolerant and 14 standing-intolerant) while performing these tasks with and without SIJ bracing. Kinematics were captured concurrently and used for movement phase identification. Cross-correlation quantified trunk coactivation and extensor timing during return-to-stand from forward flexion; root mean square amplitude quantified gluteal activity during unilateral stance. The standing-intolerant group had elevated erector spinae-external oblique coactivation without bracing, and erector spinae-internal oblique coactivation with bracing during return-to-stand compared with standing-tolerant individuals. Both groups reversed extensor sequencing during return-to-stand with bracing. Standing-tolerant individuals had higher hip abductor activity in nondominant unilateral stance and increased hip extensor activity with bracing. SIJ bracing could be a useful adjunct to other interventions targeted toward facilitating appropriate muscle activation in standing-intolerant individuals.

Relationship among Unilateral Stance Isometric Mid-thigh Pull Variables, Sprint Times, and Jump Performance in Collegiate Football Players

Relationship among Unilateral Stance Isometric Mid-thigh Pull Variables, Sprint Times, and Jump Performance in Collegiate Football Players

Effect of functional fatigue protocol on static and dynamic postural control of lower extremities

Purpose The purpose of this study was to investigate the effects of a functional fatigue protocol on lower extremity dynamic and static postural control. Methods A total of 20 physically active collegiate students participated in this study (ten males, ten females; age 22.5±2.7 years; mass 67.0±13.0 kg; height 168.0±8.9 cm). A unilateral stance with eyes closed for 10 seconds was performed to test static postural control using a balance force plate and single-leg drop landing on 30cm box was performed as a dynamic postural control test and captured using VICON motion analysis system. Results The results of this study showed an average heart rate of 176.3 beats/minute, an 18 rating on the perceived exertion scale, significant differences in blood lactate, and a static postural control deficit after fatigue as compared with before fatigue(p<.05). Dynamic postural control after fatigue changed landing strategy in the form of stiff landing. Knee flexion was decreased at initial contact and at peak vertical ground reaction force, also, both decreased valgus and internal rotation of knee joint. Conclusions This protocol may use for enhancing fatigue-endurance training as well as for inducing fatigue. Further, to ascertain a landing strategy, it is recommended to increase landing height to clearly observe changes in landing strategy.

The relationship between trunk position sense and postural control in ataxic individuals

BackgroundThe proprioceptive system plays a role in the maintenance of postural control more than the visual and vestibular systems in ataxic patients with postural control disorders, but the relationship between trunk proprioception and postural control has not been sufficiently investigated yet. This relationship can provide a different perspective to the ataxia rehabilitation. Research questionThis study aimed to examine the relationship between trunk position sense and postural control in ataxic individuals by comparing them to healthy individuals. MethodsTwenty ataxic and 20 healthy individuals were included. The Sensory Organization Test, Limits of Stability Test, and Unilateral Stance Test in the Computerized Dynamic Posturography and Berg Balance Scale were used to evaluate postural control. The Baseline Digital Inclinometer (Norwalk, CA, USA) measured trunk position sense. ResultsIt was found that repositioning error degree of the trunk position sense was higher in ataxic individuals than in healthy individuals, including scores of clinical and objective tests in postural control evaluation: they were lower in ataxic individuals (p < 0.05). As a result, trunk position sense was associated with almost all evaluated parameters, including sensory integration, postural sway, limits of stability, and functional balance (p < 0.05). SignificanceThe impairment of postural control, which is the most important cause of activity and participation limitations in ataxic patients, is not only affected by motor disorders, but by sensory disturbances. Our study demonstrated that impairment of the trunk position sense in ataxic individuals was higher than that of healthy individuals, and affected the different components of postural control.

Influence of rearfoot alignment on static and dynamic postural stability

Background/Aims: It has been postulated that foot alignment affects postural stability. However, previous studies reported contradicting results regarding the association between foot alignment and postural stability. Methods: A total of 216 healthy participants aged 15 to 24 years were recruited. Their rearfoot alignment was measured in non-weight bearing and weight-bearing positions. Their static balance was assessed using Balance Error Scoring System and dynamic balance by Star Excursion Balance Test. The relationship between the data obtained were analysed using SPSS version 22 software. Findings: A Pearson correlation with a 95% confidence interval reported that there was: (i) no significant difference in the rearfoot alignment between both genders; (ii) no significant relationship between the rearfoot alignment measured in prone lying and unilateral stance position; (iii) a weak negative correlation between the rearfoot alignment measured in prone lying position to dynamic balance on medial, posterior, lateral, anterolateral and posteromedial direction; (iv) no significant relationship between the rearfoot alignment measured in unilateral stance position to both static and dynamic postural balance. Conclusions: Rearfoot alignment measured in non-weight bearing position plays some role in postural stability and therefore should be considered in sports rehabilitation. However, this can be overlooked in rehabilitation for individuals whose postural stability is not the primary concern.

Acute and Chronic Effects of Whole-Body Vibration on Balance, Postural Stability, and Mobility in Women With Multiple Sclerosis.

The acute and chronic effects of whole-body vibration (WBV) on balance, postural stability, and mobility were evaluated in 21 women with relapsing-remitting multiple sclerosis (MS) randomly assigned to control (n = 9) or experimental (n = 12) groups. To assess acute responses, outcome variables were assessed before and immediately after a session of WBV (five 30-second bouts of vibration; frequency 30 Hz; amplitude 3 mm; 1-minute rest intervals) during their first visit (week 1) using field (Timed-Up and Go; 500-m walk; Berg Balance Scale) and laboratory tests (NeuroCom Balance Master and EquiTest System—Sensory Organization Test, Adaptation Test, Limits of Stability, Modified Clinical Test for Sensory Integration of Balance, Unilateral Stance, Tandem Walk, Step/Quick Turn). Acute responses were also measured after their fifth visit for only the Adaptation and Sensory Organization tests. For the chronic responses, participants were exposed to the WBV protocol once a week, for a total of 5 weeks, and then at week 5, were reassessed with the Adaptation and the Sensory Organization tests. Neither acute nor chronic exposure to the WBV protocols used in this study resulted in significant improvements (P > .05) in balance, postural stability, or mobility as assessed by either field or laboratory tests. However, based on promising results from other studies that have used WBV with other clinical populations, either alone or in conjunction with exercise, additional studies that increase the dose of vibration exposure, both acutely and chronically, should be conducted in patients with MS.

Static and Dynamic Balance Disorders in Patients With Rheumatoid Arthritis and Relationships With Lower Extremity Function and Deformities: A Prospective Controlled Study.

This study aims to evaluate the static and dynamic balance disorders of patients with rheumatoid arthritis (RA) and to disclose the relationships with clinical, functional, and radiological findings of lower extremities. A total of 81 patients with RA (15 males, 66 females; mean age 48.9±10.4 years; range 22 to 67 years) were compared with 84 age and sex-matched healthy controls (14 males, 70 females; mean age 45.9±12.1 years; range 24 to 70 years). Radiographic assessments of feet were performed to evaluate the presence of pes planus, hallux valgus, metatarsus primus varus, and splaying foot deformities. Foot functions of patients were determined with Foot and Ankle Outcome Score. The balance disorders of the subjects were evaluated with three static (modified clinical test of sensory interaction and balance, unilateral stance, weight bearing squat) and three dynamic (step-up-and-over, sit-to-stand, tandem walk) balance tests via the 'Neurocom Balance Master' device. Rheumatoid arthritis patients had significantly higher sway velocity in unilateral stance and modified clinical test of sensory interaction and balance tests, higher step width and lower speed when walking on a line, lower rising index and higher movement time in step-up-and-over test compared to healthy controls (p<0.05). Performances on the sit-to-stand and weight bearing squat tests were comparable between both groups. Of the patients, although 61% had hallux valgus, 52% had metatarsus primus varus, 33% had pes planus, and 26% had splaying foot, these deformities were not correlated with Foot and Ankle Outcome Score or balance disorders. Presence of swollen joint was determined as the most relevant factor for balance disorders of RA patients. Patients with RA may have increased risk for balance disorders due to cumulative effect of the lower extremity impairments seen in the course of disease.

Static and Dynamic Balance Performance and Balance Confidence in Individuals With and Without Pulmonary Arterial Hypertension.

Assessment of balance performance is important for both diagnostic and therapeutic reasons in clinical practice. Although the ideal exercise prescription is unknown for patients with pulmonary arterial hypertension (PAH), balance training may be effective for this population if they have balance impairments, such as other patients with cardiopulmonary diseases. The present study aimed to evaluate static and dynamic balance performance and balance confidence in individuals with and without PAH. Eighteen participants with PAH and 12 apparently healthy volunteers were included in this cross-sectional study. Balance performance was assessed by Balance Master System. Static balance performance was assessed by the modified Clinical Test of Sensory Interaction on Balance and unilateral stance test. Limits of stability was used for the assessment of dynamic balance performance. Balance confidence was determined using the Activities Balance Confidence scale. There was no significant difference in age, gender, and body mass index between the 2 groups. There was no significant difference in modified Clinical Test of Sensory Interaction on Balance and unilateral stance variables between the patients and healthy controls. Reaction time (forward), movement velocity (backward), directional control (backward), endpoint excursion (backward), and maximum excursion (backward) variables that were the subgroups of limits of stability were significantly different between the 2 groups (P < .05). Balance confidence was significantly lower in patients with PAH (P < .001). This study suggests that although static balance performance was preserved, patients with PAH had decreased dynamic balance performance and balance confidence without a significant fall history compared with healthy controls.

O 042 – Similarity of knee motion and muscle activity in patients with CP and stiff gait and healthy subjects during stair climbing

Many studies have reported that there are several differences between genders which may result in altered neuromuscular control. Although the existing evidence suggests that low back pain (LBP) affects the ability to control posture, there is little evidence the gender differences in postural control in people with nonspecific chronic LBP.Are there any gender differences in postural control and correlations between postural control, pain, disability, and fear of movement in people with nonspecific chronic LBP?Static and dynamic postural control were evaluated using a computerized postural control assessment tool including assessments for limits of stability (LOS), unilateral stance, and modified clinical test of sensory interaction on balance. Pain intensity and fear of movement were assessed using a visual analogue scale and the Tampa Scale of Kinesiophobia, respectively.This cross-sectional study included 51 people (25 females and 26 males) with nonspecific chronic LBP. Mean reaction time in the LOS test was significantly less in male participants compared with females when adjusted for pain intensity and disability level, F(1,45) = 4.596, p = .037, ηp2 = 0.093. There was no significant difference in the remaining LOS variables as well as unilateral stance, and modified clinical test of sensory interaction on balance variables between the genders (p > .05). Many correlations were observed between the LOS variables, pain intensity, and Tampa Scale of Kinesiophobia score in female participants (p < .05). The Tampa Scale of Kinesiophobia score was also correlated with the movement velocity and endpoint excursion in the LOS test in the male participants (p < .05).This study suggests that there is no difference in most of the static and dynamic postural control variables between females and males; however, higher fear of movement, and pain intensity during activity are more associated with impaired dynamic balance in females with nonspecific chronic LBP.

Gender differences in postural control in people with nonspecific chronic low back pain

BackgroundMany studies have reported that there are several differences between genders which may result in altered neuromuscular control. Although the existing evidence suggests that low back pain (LBP) affects the ability to control posture, there is little evidence the gender differences in postural control in people with nonspecific chronic LBP. Research questionAre there any gender differences in postural control and correlations between postural control, pain, disability, and fear of movement in people with nonspecific chronic LBP? MethodsStatic and dynamic postural control were evaluated using a computerized postural control assessment tool including assessments for limits of stability (LOS), unilateral stance, and modified clinical test of sensory interaction on balance. Pain intensity and fear of movement were assessed using a visual analogue scale and the Tampa Scale of Kinesiophobia, respectively. ResultsThis cross-sectional study included 51 people (25 females and 26 males) with nonspecific chronic LBP. Mean reaction time in the LOS test was significantly less in male participants compared with females when adjusted for pain intensity and disability level, F(1,45) = 4.596, p = .037, ηp2 = 0.093. There was no significant difference in the remaining LOS variables as well as unilateral stance, and modified clinical test of sensory interaction on balance variables between the genders (p > .05). Many correlations were observed between the LOS variables, pain intensity, and Tampa Scale of Kinesiophobia score in female participants (p < .05). The Tampa Scale of Kinesiophobia score was also correlated with the movement velocity and endpoint excursion in the LOS test in the male participants (p < .05). SignificanceThis study suggests that there is no difference in most of the static and dynamic postural control variables between females and males; however, higher fear of movement, and pain intensity during activity are more associated with impaired dynamic balance in females with nonspecific chronic LBP.

Asymmetries in Isometric Force-Time Characteristics Are Not Detrimental to Change of Direction Speed.

Dos'Santos, T, Thomas, C, Jones, PA, and Comfort, P. Asymmetries in isometric force-time characteristics are not detrimental to change of direction speed. J Strength Cond Res 32(2): 520-527, 2018-The purpose of this study was to determine the impact of between-limb asymmetries in isometric midthigh pull (IMTP) force-time characteristics on change of direction speed (CODS). Twenty multisport collegiate athletes (mean ± SD: age: 21.0 ± 1.9 years; mass: 78.7 ± 8.9 kg; and height: 1.77 ± 0.04 m) performed 3 unilateral stance IMTP trials per limb and 3 modified 505 CODS trials each side to establish imbalances between left and right and dominant (D) and nondominant (ND) limbs. Limb dominance was defined as the limb that produced the highest isometric force-time value or faster CODS performance. Paired sample t-tests and Hedges g effect sizes revealed no significant differences in IMTP force-time characteristics and CODS performance between left and right limbs (p > 0.05, g ≤ 0.37). However, significant differences were observed between D and ND limbs for all IMTP force-time characteristics and CODS performance (p < 0.001, g = 0.39-0.73). No significant correlations were observed between IMTP asymmetries and CODS asymmetry (p ≥ 0.380, r ≤ -0.35), and no significant differences were observed in CODS performance between athletes of lesser and greater IMTP asymmetries (p ≥ 0.10, g ≤ 0.76). Poor percentage agreements (40-60%) between like-for-like classifications of asymmetry (i.e., either both asymmetrical or both balanced) for CODS and IMTP force-time characteristics were demonstrated. Asymmetries in IMTP force-time characteristics and CODS performance were present; however, greater IMTP asymmetries had no detrimental impact on CODS performance and did not equate to greater asymmetries in CODS performance. Therefore, collegiate athletes with asymmetries within the range reported within this study (≤13%) should not experience detriments to CODS or faster performance from that limb during 180° turns.

Side-to-side difference in dynamic unilateral balance ability and pitching performance in Japanese collegiate baseball pitchers.

[Purpose] To evaluate the side-to-side difference in dynamic unilateral balance ability and to determine the correlation of the balance ability with pitching performance in collegiate baseball pitchers. [Subjects and Methods] Twenty-five Japanese collegiate baseball pitchers participated in this study. Dynamic balance ability during a unilateral stance was bilaterally evaluated using the star excursion balance test (SEBT). The pitchers threw 20 fastballs at an official pitching distance; the maximal ball velocity and pitching accuracy (the number of strike/20 pitches × 100) were assessed. Side-to-side difference in scores of SEBT was assessed using a paired t-test. Correlations between SEBT scores and pitching performance were evaluated for both legs using a Pearson’s correlation analysis. [Results] The pivot side showed significantly higher score of the SEBT in the anteromedial direction than the stride side. On the other hand, the SEBT scores in the pivot and stride legs did not have significant correlations with maximal ball velocity and pitching accuracy. [Conclusion] These findings suggest that marked side-to-side difference does not exist in the dynamic unilateral balance ability of collegiate baseball pitchers and that the dynamic unilateral balance ability of each leg is not directly related to maximal ball velocity and pitching accuracy.

Use of a Dynamic Balance System to Quantify Postural Steadiness and Stability of Individuals with Lower-Limb Amputation: A Pilot Study

ABSTRACT Introduction Despite rehabilitation and gait training, the gait of individuals with lower-limb amputation is often asymmetric and falls and/or fear of falling are common. Clinical assessments of balance and stability include the Berg Balance Scale and the Dynamic Gait Index. Biomechanical assessments, conducted largely in research laboratories, are more objective, quantitative, and may provide greater resolution. These biomechanical measures include postural sway during both unilateral and bilateral standing tasks and the dynamic postural response to applied or volitional perturbations. The objective of this study was to investigate the utility of a dynamic balance system, a relatively new clinical tool incorporating dual force plates similar to that used in research laboratories, to assess the postural steadiness and stability of a small, diverse population of persons with lower-limb amputation. The specific aim was to investigate whether differences in balance of persons with amputation due to changes in prosthetic componentry were reflected in the resultant data. Materials and Methods Dynamic balance testing was conducted using the Bertec Balance Advantage–Dynamic CDP system on five adult subjects with varying levels of lower-limb amputation. Trials were conducted in both the subjects' current prosthesis and alternative prosthetic componentry after a 1-week acclimation period. Specific tasks included limits of stability, weight-bearing squats, and unilateral stance. Results Subjects had difficulty shifting their weight during the limits of stability task; both the maximum excursion and anteroposterior directional control varied with prosthetic componentry. Load sharing also varied with prosthetic componentry. Load sharing became more asymmetric as knee flexion increased during the weight-bearing bilateral squat tasks, with less weight supported on the prosthetic limb. Finally, the metrics for the unilateral stance task varied with prosthetic componentry. Conclusions The dynamic balance system tasks and related metrics demonstrated the potential to discern differences in balance in persons with amputation due to changes in prosthetic componentry. Further study is needed to investigate these parameters, their correlation with clinical measures of balance, and the effects of both prosthetic componentry and alignment.

Influence of military workload and footwear on static and dynamic balance performance

Balance performance have been shown to be influenced by footwear design characteristics and physiological workloads. This study was conducted to assess the impact of two military footwear, standard (STD) and minimalist (MIN) boots, on human balance before (PRE) and after (POST) a simulated military type, load carriage exercise. Twenty two male participants [age: 22.14 ± 2.68 years; height: 176.69 ± 6.82 cm; weight: 79.81 ± 9.70 kg] were tested for balance in bilateral and unilateral stances with and without challenging sensory information and using a star excursion balance test (SEBT). Center of pressure postural sway variables from different balance testing conditions and reach distances from SEBT, were analyzed using a 2(STD-MIN) x 2(PRE-POST) repeated measures analysis of variance. Results revealed significantly greater postural sway in the STD boot and in POST workload conditions. Decrements in balance can be attributed to boot design characteristics and muscular exertion due to the workload.

STATIC BALANCE MEASUREMENTS IN STABLE AND UNSTABLE CONDITIONS DO NOT DISCRIMINATE GROUPS OF YOUNG ADULTS ASSESSED BY THE FUNCTIONAL MOVEMENT SCREEN™ (FMS™).

The Functional Movement Screen™ (FMS™) has been the focus of recent research related to movement profiling and injury prediction. However, there is a paucity of studies examining the associations between physical performance tasks such as balance and the FMS™ screening system. The purpose of this study was to compare measures of static balance in stable and unstable conditions between different groups divided by FMS™ scores. A secondary purpose was to discern if balance indices discriminate the groups divided by FMS™ scores. Cross-sectional study. Fifty-seven physically active subjects (25 men and 32 women; mean age of 22.9 ± 3.1 yrs) participated. The outcome was unilateral stance balance indices, composed by: Anteroposterior Index; Medial-lateral Index, and Overall Balance Index in stable and unstable conditions, as provided by the Biodex balance platform. Subjects were dichotomized into two groups, according to a FMS™ cut-off score of 14: FMS1 (score > 14) and FMS2 (score ≤ 14). The independent Students t-test was used to verify differences in balance indices between FMS1 and FMS2 groups. A discriminant analysis was applied in order to identify which of the balance indices would adequately discriminate the FMS™ groups. Comparisons between FMS1 and FMS2 groups in the stable and unstable conditions demonstrated a higher unstable Anteroposterior index for FMS2 (p=0.017). No significant differences were found for other comparisons (p>0.05). The indices did not discriminate the FMS™ groups (p > 0.05). The balance indices adopted in this study were not useful as a parameter for identification and discrimination of healthy subjects assessed by the FMS™. 2c.

Investigating Human Balance and Postural Control During Bilateral Stance on BOSU Balance Trainer

Balance and postural control are essential for performing activities of daily living to minimize risks of fall and injury. A proven way to improve postural stability and the perception of the somatosensory system is to utilize devices such as the BOSU balance trainer, wobble board and seesaw platform. It was reported that performing unilateral stance on BOSU could stimulate and eventually improve human neuromuscular system in maintaining body balance. However, this posture is challenging and may not be suitable for individuals with sedentary lifestyle. Therefore, this study investigates the ability of human postural control while performing bilateral stance on BOSU. Increase in center of pressure measures e.g. sway area, sway velocity, and the range of excursion in both anterior–posterior and medial–lateral directions were observed when subjects stood on BOSU, as compared to when they stood on the flat ground (p < 0.01). This study also found that vision played an important role in challenging environment. Significant differences were found when subjects were standing on BOSU with eyes closed and eyes open (p < 0.01). Hence, it can be deduced that bilateral stance on BOSU can stimulate neuromuscular system to coordinate the lower extremity in order to mitigate the instability and to reduce the risk of fall. Individuals with sedentary lifestyle or impaired balance, or patients who are recovering from minor ankle or knee injury can perform bilateral stance on BOSU, instead of unilateral stance to improve their balance and postural control.

Relationship between postural instability and subcortical volume loss in Alzheimer's disease.

The relationship between postural instability and subcortical structure in AD has received less attention. The aims of this study were to assess whether there are differences in the ability to control balance between Alzheimer's disease (AD) and controls, and to investigate the association between subcortical gray matter volumes and postural instability in AD.We enrolled 107 consecutive AD patients and 37 controls. All participants underwent detailed neuropsychological evaluations, T1-weighted MRI at 3 T, and posture assessment using computerized dynamic posturography. We segmented the volumes of 6 subcortical structures of the amygdala, thalamus, caudate nucleus, putamen, globus pallidus and nucleus accumbens, and of hippocampus, using the FMRIBs integrated registration and segmentation tool.All subcortical structures, except for the globus pallidus, were smaller in AD compared with controls on adjusting for age and gender. Falling frequencies in unilateral stance test (UST) and composite scores in sensory organization test (SOT) were worse in AD than in controls. The motor control test did not reveal any differences between groups. On subgroup analyses in AD, the groups with poor performance in UST or SOT exhibited significantly reduced nucleus accumbens and putamen volumes, and nucleus accumbens volume, respectively. The smaller volume of the nucleus accumbens was associated with postural instability in AD (OR [95% CI] 17.847 [2.59–122.80] for UST, 42.827[6.06–302.47] for SOT, all P < .05).AD patients exhibited reduced ability to control balance compared with controls, and this postural instability was associated with nucleus accumbens volume loss. Furthermore, cognitive dysfunction was more prominent in the group with severe postural instability.

Quantification of postural control deficits in patients with recent concussion: an inertial-sensor based approach

ObjectiveTo quantify postural control ability in a group with concussion compared with a ‘healthy’ control group.DesignCase-control study.SettingUniversity Biomechanics Laboratory.ParticipantsFifteen concussion patients (4 females, 11 males) and a group of fifteen age- and sex- matched controls. Participants were excluded if they had any: lower extremity injury that may affect gait; history of cognitive deficiencies; history of ≥3 previous concussions; loss of consciousness following the concussion for &gt;1 minute; a previously documented concussion in the previous yearIndependent variableGroup; Task (3 stance variants of the Balance Error Scoring System [BESS])Outcome measuresSway area as computed using a force-plate and sway volume as computed from an accelerometer placed on the sacrum during performance of the BESS.Main resultsConcussed patients exhibited increased sway area (1500 mm2[95% CI: 900 to 2000 mm2] vs 650 mm2[95% CI: 520 to 780 mm2] p=0.02) and sway volume (9.5 m3s–6[95%CI: 8 to 20 m3s–6] vs 2.80 m3s–6[95% CI: 1.8 to 3.6 m3s–6]) in the bilateral stance position of the BESS. The sway volume metric also had excellent accuracy in identifying task ‘errors’ (tandem stance: 95% CI: 80–96%, p&lt;0.001; unilateral stance: 95% CI: 85–95%, p&lt;0.001).ConclusionsIndividuals with concussion display increased postural sway during bilateral stance. The sway volume that was calculated from the accelerometer data not only differentiated a group with concussion from a healthy control group, but successfully identified when task errors had occurred. This may be of value in the development of a pitch-side assessment system for concussion.Competing interestsNone.