Deficits in medio-lateral balance control and the implications for falls in individuals with multiple sclerosis

Testing Dynamic Balance in People with Multiple Sclerosis: A Correlational Study between Standard Posturography and Robotic-Assistive Device

BACKGROUND

Robotic devices are known to provide pivotal parameters to assess motor functions in Multiple Sclerosis (MS) as dynamic balance. However, there is still a lack of validation studies comparing innovative technologies with standard solutions. Thus, this study's aim was to compare the postural assessment of fifty people with MS (PwMS) during dynamic tasks performed with the gold standard EquiTest® and the robotic platform hunova®, using Center of Pressure (COP)-related parameters and global balance indexes.

METHODS

Pearson's ρ correlations were run for each COP-related measure and the global balance index was computed from EquiTest® and hunova® in both open (EO) and closed-eyes (EC) conditions.

RESULTS

Considering COP-related parameters, all correlations were significant in both EO (0.337 ≤ ρ ≤ 0.653) and EC (0.344 ≤ ρ ≤ 0.668). Furthermore, Pearson's analysis of global balance indexes revealed relatively strong for visual and vestibular, and strong for somatosensory system associations (ρ = 0.573; ρ = 0.494; ρ = 0.710, respectively).

CONCLUSIONS

Findings confirm the use of hunova® as a valid device for dynamic balance assessment in MS, suggesting that such a robotic platform could allow for a more sensitive assessment of balance over time, and thus a better evaluation of the effectiveness of personalized treatment, thereby improving evidence-based clinical practice.

The effect of hip abductor strengthening exercises on lower limb strength asymmetry and balance in women with multiple sclerosis: A randomized controlled clinical trial

INTRODUCTION

Patients with multiple sclerosis tend to use and move their body segments in an unbalanced way, which causes asymmetry of muscle strength, especially in the lower limbs. Among these muscles, the hip abductor muscles play a more important role in stabilizing the pelvis and maintaining balance. The purpose of this research was to investigate the effect of hip abductors exercises on lower limb strength asymmetry and balance in people with multiple sclerosis.

MATERIALS & METHODS

In this clinical trial with a pre-test-post-test design, 40 women with multiple sclerosis were purposefully selected and randomly divided into experimental and control groups. The experimental group performed hip abductor muscle strengthening exercises for 8 weeks and each session lasted 30 min. The control group did not receive any intervention and continued their daily activities. The strength of knee flexors and extensors, plantar-flexors and ankle dorsi-flexors was measured using a dynamometer. Static and dynamic balance was also evaluated using the stork test and timed get up and go test, respectively. ANCOVA test was used at a significance level of 0.05 to investigate the intergroup effects.

RESULTS

The results showed a significant decrease in the strength asymmetry of the knee extensor (P = 0.001) and knee flexor (P = 0.001) muscles in the experimental group. However, no significant difference was observed in the asymmetry of the strength of the ankle dorsi-flexor (P = 0.160) and plantar-flexor muscles (P = 0.698). The results also showed a significant improvement in static (P = 0.001) and dynamic balance (P = 0.001) in the experimental group.

DISCUSSIONS & CONCLUSIONS

Strengthening the hip abductors improves the symmetry of the strength of the knee extensor and flexor muscles. It also improves the balance of people with multiple sclerosis.

Effect of Robotic-Assisted Gait at Different Levels of Guidance and Body Weight Support on Lower Limb Joint Kinematics and Coordination

The Lokomat provides task-oriented therapy for patients with gait disorders. This robotic technology drives the lower limbs in the sagittal plane. However, normative gait also involves motions in the coronal and transverse planes. This study aimed to compare the Lokomat with Treadmill gait through three-dimensional (3D)-joint kinematics and inter-joint coordination. Lower limb kinematics was recorded in 18 healthy participants who walked at 3 km/h on a Treadmill or in a Lokomat with nine combinations of Guidance (30%, 50%, 70%) and bodyweight support (30%, 50%, 70%). Compared to the Treadmill, the Lokomat altered pelvic rotation, decreased pelvis obliquity and hip adduction, and increased ankle rotation. Moreover, the Lokomat resulted in significantly slower velocity at the hip, knee, and ankle flexion compared to the treadmill condition. Moderate to strong correlations were observed between the Treadmill and Lokomat conditions in terms of inter-joint coordination between hip-knee (r = 0.67-0.91), hip-ankle (r = 0.66-0.85), and knee-ankle (r = 0.90-0.95). This study showed that some gait determinants, such as pelvis obliquity, rotation, and hip adduction, are altered when walking with Lokomat in comparison to a Treadmill. Kinematic deviations induced by the Lokomat were most prominent at high levels of bodyweight support. Interestingly, different levels of Guidance did not affect gait kinematics. The present results can help therapists to adequately select settings during Lokomat therapy.

Immediate effects of wearing textured versus smooth insoles on standing balance and spatiotemporal gait patterns when walking over even and uneven surfaces in people with multiple sclerosis

PURPOSE

To investigate the immediate effects of wearing novel sensory-stimulating textured insoles on balance and gait in 41 people with multiple sclerosis (pwMS).

MATERIALS AND METHODS

Assessments of balance (firm/foam surface; eyes open/closed) and walking (when negotiating even/uneven surfaces) were performed wearing textured insoles, smooth insoles, shoes only, and barefoot. Outcome measures were centre of pressure (CoP) movement during standing (elliptical area, sway path velocity) and spatiotemporal gait patterns (stride/step width, stride time, double-limb support time, stride length, velocity).

RESULTS

Wearing textured insoles led to reductions in CoP velocity measures when standing on foam with eyes open and closed when compared to barefoot (p values ≤0.02). Textured insoles did not appear to be consistently superior to smooth insoles or shoes only for improving gait. Relative to the insole/shoe conditions, walking barefoot led to poorer gait performance for the even and uneven surface tasks (p values ≤0.03).

CONCLUSIONS

For pwMS, stimulating the foot with "texture" appears to provide enhanced sensory input with the capacity to improve CoP movement control during standing; offering a potential new treatment option for balance rehabilitation. Further research is needed to identify which individuals may benefit most from textured insoles.Implications for rehabilitationTextured shoe insoles, designed to stimulate plantar mechanoreceptors, are a novel approach to improve standing balance and walking patterns in people with multiple sclerosis (pwMS).Wearing textured insoles for the first time can lead to improvements in centre of pressure movement control when standing on an unstable compliant supporting surface.Textured insoles offer a potential new treatment technique for balance rehabilitation in pwMS who show early signs of diminished foot sensation.

Detection of Fall Risk in Multiple Sclerosis by Gait Analysis-An Innovative Approach Using Feature Selection Ensemble and Machine Learning Algorithms

One of the common causes of falls in people with Multiple Sclerosis (pwMS) is walking impairment. Therefore, assessment of gait is of importance in MS. Gait analysis and fall detection can take place in the clinical context using a wide variety of available methods. However, combining these methods while using machine learning algorithms for detecting falls has not been performed. Our objective was to determine the most relevant method for determining fall risk by analyzing eleven different gait data sets with machine learning algorithms. In addition, we examined the most important features of fall detection. A new feature selection ensemble (FS-Ensemble) and four classification models (Gaussian Naive Bayes, Decision Tree, k-Nearest Neighbor, Support Vector Machine) were used. The FS-Ensemble consisted of four filter methods: Chi-square test, information gain, Minimum Redundancy Maximum Relevance and RelieF. Various thresholds (50%, 25% and 10%) and combination methods (Union, Union 2, Union 3 and Intersection) were examined. Patient-reported outcomes using specialized walking questionnaires such as the 12-item Multiple Sclerosis Walking Scale (MSWS-12) and the Early Mobility Impairment Questionnaire (EMIQ) achieved the best performances with an F1 score of 0.54 for detecting falls. A combination of selected features of MSWS-12 and EMIQ, including the estimation of walking, running and stair climbing ability, the subjective effort as well as necessary concentration and walking fluency during walking, the frequency of stumbling and the indication of avoidance of social activity achieved the best recall of 75%. The Gaussian Naive Bayes was the best classification model for detecting falls with almost all data sets. FS-Ensemble improved the classification models and is an appropriate technique for reducing data sets with a large number of features. Future research on other risk factors, such as fear of falling, could provide further insights.

Reliability of the Wii Balance Board for measurement of steady state balance in children aged 6-9 years

PURPOSE

The Wii Balance Board (WBB) can be used for assessment of steady state balance (SSB), but its reliability has not been studied in children aged 6-9 years. This study aimed to determine the test-retest reliability of the WBB for measuring SSB in this population. A secondary aim was to determine the minimum detectable change (MDC) and standard error of measurement (SEM) of the WBB in children aged 6-9 years.

METHODS

52 children between 6-9 years of age participated. "One leg stand balance" was used to assess center of pressure velocity (COPV) and center of pressure area (COPA) on three occasions by the same tester. Two tests were conducted on the same day (Day 1) and the third test was performed on another day (Day 2), with a period of 5-13 days between the two test days. Intraclass correlation coefficient (ICC 3,1), SEMs, and MDC were calculated.

RESULTS

Intra-day test-retest reliability of COPA was found to be good (ICC3,1 =0.86; 95% confidence interval [CI]: 0.75, 0.92) and that of COPV was also found to be good (ICC3,1 =0.87; 95% CI: 0.77, 0.92). Inter-day test-retest reliability was found to be good for COPA (ICC3,1 = 0.87; 95% CI: 0.75, 0.93) and COPV (ICC3,1 = 0.89; 95% CI: 0.81, 0.94). SEM for COPA in intra-day testing was 18.90 mm2 (15.78%), and in inter-day testing it was 16.44 mm2 (13.61%). SEM for COPV in intra-day testing was 1.12 mm/s (7.6%), and in inter-day testing it was 1.01 mm/s (6.9%). MDC for COPA in intra-day testing was 52.41mm2 (42.75%), and in inter-day testing was 45.58 mm2 (35.75%). MDC for COPV in intra-day testing was 3.11 mm/s (21.2%), and in inter-day testing it was 2.80 mm/s (18.9%).

CONCLUSION

The WBB has good test-retest reliability for assessing SSB of children between 6-9 years. COPA measurements appear to be less sensitive to clinical changes in SSB when compared to COPV. Assessment of validity of the WBB in this age group is recommended before it can be considered as a potential balance assessment tool in children.

Static posturography as a novel measure of the effects of aging on postural control in dogs

Aging is associated with impairment in postural control in humans. While dogs are a powerful model for the study of aging, the associations between age and postural control in this species have not yet been elucidated. The aims of this work were to establish a reliable protocol to measure center of pressure excursions in standing dogs and to determine age-related changes in postural sway. Data were obtained from 40 healthy adult dogs (Group A) and 28 senior dogs (Group B) during seven trials (within one session of data collection) of quiet standing on a pressure sensitive walkway system. Velocity, acceleration, root mean square, 95% ellipse area, range and frequency revolve were recorded as measures of postural sway. In Group A, reliability was assessed with intraclass correlation, and the effect of morphometric variables was evaluated using linear regression. By means of stepwise linear regression we determined that root mean square overall and acceleration in the craniocaudal direction were the best variables able to discriminate between Group A and Group B. The relationship between these two center-of-pressure (COP) measures and the dogs’ fractional lifespan was examined in both groups and the role of pain and proprioceptive deficits was evaluated in Group B. All measures except for frequency revolve showed good to excellent reliability. Weight, height and length were correlated with most of the measures. Fractional lifespan impacted postural control in Group B but not Group A. Joint pain and its interaction with proprioceptive deficits influence postural sway especially in the acceleration in the craniocaudal direction, while fractional lifespan was most important in the overall COP displacement. In conclusion, our study found that pressure sensitive walkway systems are a reliable tool to evaluate postural sway in dogs; and that postural sway is affected by morphometric parameters and increases with age and joint pain.

Balance Adaptation While Standing on a Compliant Base Depends on the Current Sensory Condition in Healthy Young Adults

Background

Several investigations have addressed the process of balance adaptation to external perturbations. The adaptation during unperturbed stance has received little attention. Further, whether the current sensory conditions affect the adaptation rate has not been established. We have addressed the role of vision and haptic feedback on adaptation while standing on foam.

Methods

In 22 young subjects, the analysis of geometric (path length and sway area) and spectral variables (median frequency and mean level of both total spectrum and selected frequency windows) of the oscillation of the centre of feet pressure (CoP) identified the effects of vision, light-touch (LT) or both in the anteroposterior (AP) and mediolateral (ML) direction over 8 consecutive 90 s standing trials.

Results

Adaptation was obvious without vision (eyes closed; EC) and tenuous with vision (eyes open; EO). With trial repetition, path length and median frequency diminished with EC (p < 0.001) while sway area and mean level of the spectrum increased (p < 0.001). The low- and high-frequency range of the spectrum increased and decreased in AP and ML directions, respectively. Touch compared to no-touch enhanced the rate of increase of the low-frequency power (p < 0.05). Spectral differences in distinct sensory conditions persisted after adaptation.

Conclusion

Balance adaptation occurs during standing on foam. Adaptation leads to a progressive increase in the amplitude of the lowest frequencies of the spectrum and a concurrent decrease in the high-frequency range. Within this common behaviour, touch adds to its stabilising action a modest effect on the adaptation rate. Stabilisation is improved by favouring slow oscillations at the expense of sway minimisation. These findings are preliminary to investigations of balance problems in persons with sensory deficits, ageing, and peripheral or central nervous lesion.

Sample entropy discriminates balance performance of older cannabis users from non-users

BACKGROUND

Maintaining an upright stance involves a complex interaction of sensory processing and motor outputs to adequately perform this fundamental motor skill. Aging and cannabis use independently disrupt balance performance, but our recent data did not find differences in static balance performance between older cannabis Users and older Non-Users using traditional linear measures (i.e., characteristics of the center of pressure sway). The purpose of this analysis was to determine whether an unbiased entropy measure (sample entropy) can differentiate postural control (standing posture) strategies between older cannabis Users and Non-Users when typical linear measures could not.

METHODS

Eight medical cannabis Users and eight age- and sex-matched controls completed static posturography testing in an eyes-open condition for 60 s. Linear measures included pathlength of the anterior-posterior and medio-lateral directions and an ellipse that encapsulates 95% of the 2D area explored. The nonlinear measure was the sample entropy of the center of pressure time-series in anterior-posterior and medio-lateral directions. Group comparisons were accomplished via pairwise testing and effect size calculations.

FINDINGS

The statistical testing revealed that sample entropy in the anterior-posterior direction was significantly larger in the Users (mean ± SD = 0.29 ± 0.08) compared to the Non-Users (0.19 ± 0.05; P = 0.01, d = 1.55).

INTERPRETATION

This finding indicates that the Users had a decreased regularity of their center of pressure signal in the anterior-posterior direction, which might reflect reduced balance adaptability and accompanies the increased fall risk observed in our recent report on these same subjects.

Quantifying fear of falling by utilizing objective body sway measures: A 360° virtual video study

BACKGROUND

Fear of falling (FOF) is a psychological condition that can lead to increased morbidity and mortality in the elderly population. However, the subjective and multidimensional nature of FOF results in limitations of existing FOF measurement tools, which could influence the generalization of the findings from various studies. An objective measure of FOF could address those limitations. The present study aimed to identify the feasibility of using center of pressure (COP) parameters to quantify FOF.

RESEARCH QUESTION

(1) Are 360º roller coaster videos effective to induce FOF? And (2) Which COP parameter(s) is/are feasible to quantify FOF?

METHODS

Nineteen young, healthy adults (24 ± 2.47 years) were recruited in the present study. Subjects were required to watch three 360º videos: one control video and two roller coaster videos, through virtual reality goggles during standing and sitting. Six trials (3 during standing and 3 during sitting) with video were performed. Subjects were required to rate their FOF on a visual analogue scale after watching each video. COP mean power frequency, COP root mean square, and COP range were measured. The Friedman test was used to assess differences in COP parameters under different video conditions, and Spearman's correlation analysis was used to assess the relationship between FOF and COP parameters.

RESULTS

Similar COP changes were observed in sitting and standing conditions. With increased FOF, participants demonstrated decreased COP mean power frequency and increased COP root mean square in the medial-lateral direction during both sitting and standing.

SIGNIFICANCE

Our study provided evidence that 360º roller coaster videos are effective tools to induce FOF and change in COP parameters. The relationship between FOF and COP parameters suggests that the measurement of body sway may be an objective way to quantify FOF. More research are needed to solidify the evidence.

Changes in trunk and head acceleration during the 6-minute walk test and its relation to falls risk for adults with multiple sclerosis

For persons with multiple sclerosis (MS), the general decline in neuromuscular function underlies diminished balance, impaired gait and consequently, increased risk of falling. During gait, optimal control of head motion is an important feature which is achieved partly through control of the trunk-neck region to dampen gait-related oscillations. The primary aim of this study was to examine the effect performing a 6-minute walk test (6MWT) has on head, neck and trunk accelerations in individuals with MS. This was addressed using a repeated measures generalized linear model. We were also interested in assessing whether the 6MWT has an impact on a person's falls risk and specific physiological measures related to falls. Finally the relation between the amplitude (i.e., mean RMS) of head and trunk accelerations and falls risk was examined using linear regression. The main results were that over the course of the 6MWT, individuals progressively slowed down coupled with a concurrent increase in gait-related upper body accelerations (p's > 0.05). Despite the increased acceleration, no significant changes in attenuation from the trunk to the head were observed, indicating that persons were able to maintain an optimal level of control over these oscillations. Performing the 6MWT also had a negative impact on posture, with falls risk significantly increasing following this test (p > 0.05). Interestingly, the overall falls risk values were strongly linked with vertical accelerations about the trunk and head, but not average walking speed during the 6MWT. Overall, performing the 6MWT leads to changes in walking speed, upper body acceleration patterns and increases in overall falls risk.

The Relationship between Cognitive Dysfunction and Postural Stability in Multiple Sclerosis

Background and Objectives: Multiple Sclerosis (MS) is a demyelinating disease of the central nervous system (CNS), most commonly characterized by balance dysfunction, fatigue syndrome and cognitive impairment. The goal of our study was to determine the association between cognitive functions and static posture control. Materials and Methods: The research group consisted of 76 randomized MS patients (ICDG 35.0) hospitalized at the Neurological Rehabilitation Clinic of the Medical University of Lodz. This group was divided into three subgroups according to the cognitive assessment based on the Mini Mental State Examination (MMSE) for patients over 65 years of age and the Montreal Cognitive Assessment (MoCA) under the age of 65. Fatigue syndrome was assessed using the Fatigue Severity Scale (FSS), and postural stability using a stabilometric platform. Results: The men demonstrated poorer stabilometric platform measurements than the women. Statistically significant differences were observed between patients without dysfunction and severe cognitive impairment. The results of the stabilometric platform were found to correlate with body mass index in all three groups of patients (Spearman’s test). Conclusions: Body mass index and cognition have impact on postural stability in MS patients with moderate disability and fatigue syndrome.

Specific Posture-Stabilising Effects of Vision and Touch Are Revealed by Distinct Changes of Body Oscillation Frequencies

We addressed postural instability during stance with eyes closed (EC) on a compliant surface in healthy young people. Spectral analysis of the centre of foot pressure oscillations was used to identify the effects of haptic information (light-touch, EC-LT), or vision (eyes open, EO), or both (EO-LT). Spectral median frequency was strongly reduced by EO and EO-LT, while spectral amplitude was reduced by all "stabilising" sensory conditions. Reduction in spectrum level by EO mainly appeared in the high-frequency range. Reduction by LT was much larger than that induced by the vision in the low-frequency range, less so in the high-frequency range. Touch and vision together produced a fall in spectral amplitude across all windows, more so in anteroposterior (AP) direction. Lowermost frequencies contributed poorly to geometric measures (sway path and area) for all sensory conditions. The same subjects participated in control experiments on a solid base of support. Median frequency and amplitude of the spectrum and geometric measures were largely smaller when standing on solid than on foam base but poorly affected by the sensory conditions. Frequency analysis but not geometric measures allowed to disclose unique tuning of the postural control mode by haptic and visual information. During standing on foam, the vision did not reduce low-frequency oscillations, while touch diminished the entire spectrum, except for the medium-high frequencies, as if sway reduction by touch would rely on rapid balance corrections. The combination of frequency analysis with sensory conditions is a promising approach to explore altered postural mechanisms and prospective interventions in subjects with central or peripheral nervous system disorders.

Kohonen Neural Network Investigation of the Effects of the Visual, Proprioceptive and Vestibular Systems to Balance in Young Healthy Adult Subjects

Kohonen neural network (KNN) was used to investigate the effects of the visual, proprioceptive and vestibular systems using the sway information in the mediolateral (ML) and anterior-posterior (AP) directions, obtained from an inertial measurement unit, placed at the lower backs of 23 healthy adult subjects (10 males, 13 females, mean (standard deviation) age: 24.5 (4.0) years, height: 173.6 (6.8) centimeter, weight: 72.7 (9.9) kg). The measurements were based on the modified Clinical Test of Sensory Interaction and Balance (mCTSIB). KNN clustered the subjects’ time-domain sway measures by processing their sway’s root mean square position, velocity, and acceleration. Clustering effectiveness was established using external performance indicators such as purity, precision-recall, and F-measure. Differences in these measures, from the clustering of each mCTSIB condition with its condition, were used to extract information about the balance-related sensory systems, where smaller values indicated reduced sway differences. The results for the parameters of purity, precision, recall, and F-measure were higher in the AP direction as compared to the ML direction by 7.12%, 11.64%, 7.12%, and 9.50% respectively, with their differences statistically significant (p < 0.05) thus suggesting the related sensory systems affect majorly the AP direction sway as compared to the ML direction sway. Sway differences in the ML direction were lowest in the presence of the visual system. It was concluded that the effect of the visual system on the balance can be examined mostly by the ML sway while the proprioceptive and vestibular systems can be examined mostly by the AP direction sway.

The effect of shoe cushioning on gait and balance in females with multiple sclerosis

Gait and balance deficits are significant concerns for people with multiple sclerosis (MS). Shoe cushioning can influence mobility and balance, but its effect on walking and balance remains unknown in MS. This study aimed to determine how shoe cushioning affects gait and balance in females with MS (FwMS). We hypothesized that extra cushioning would improve gait but reduce balance performance. FwMS performed gait (n = 18) and balance (n = 17) assessments instrumented using inertial sensors in two different shoe conditions: a standard-cushioned and an extra-cushioned shoe. Care was taken to ensure minimal differences between shoe types other than midsole cushioning, but shoe construction was not identical between conditions. Spatiotemporal gait parameters were assessed during a 2-min walk test, while postural sway measures were evaluated using the modified Clinical Test of Sensory Interaction and Balance. In the extra-cushioned shoe, FwMS spent less time in the double support and stance phase with more time in the single support and swing phase. No differences in stride length, gait speed, or elevation at midswing were observed between shoe conditions. Decreased path length, RMS sway, and sway velocity were observed in the extra-cushioned shoe. No differences were observed in the gait cycle's spatial composition between shoe conditions, but FwMS demonstrated improvements in the gait cycle's temporal parameters and postural sway in the extra-cushioned shoe. This may suggest a less cautious walking strategy and improved balance when wearing a shoe with extra cushioning.

Effect of Neuromuscular Exercises on Strength, Proprioceptive Receptors, and Balance in Females with Multiple Sclerosis

Background:

Multiple sclerosis (MS) is the third most common cause of adult neurologic disabilities. The aim of this study was to determine the effect of 8 weeks of neuromuscular exercises on strength, proprioceptive receptors, and balance of women with MS.

Methods:

In this randomized controlled trial study, 20 female volunteers with relapsing-remitting MS were randomly assigned into the experimental group (n = 10) and control group (n = 10). Maximum muscular strength of knee extensor and flexor muscles, knee joint proprioceptive error (Biodex), and balance (Berg Balance Scale) was measured at baseline and after 8 weeks of neuromuscular exercise. The data were analyzed using paired t-test and independent t-test.

Results:

The results showed a significant improvement (P < 0.05) in the quadriceps strength, hamstring strength, proprioceptive receptor error, and the balance in the experimental group, but not in the control group. A significant difference was evident between the experimental and control groups in terms of strength, balance, and proprioceptive receptor error (P < 0.05).

Conclusions:

Neuromuscular exercise training is effective in improving balance, strength, and reducing the proprioceptive error in people with MS, and it could be recommended as modalities for these patients.

The effects of supervised versus home Pilates-based core stability training on lower extremity muscle strength and postural sway in people with multiple sclerosis

BACKGROUND

Pilates-based core stability training (PBCST) is a controlled form of exercise that may improve the transmission of torque from the upper extremities and trunk to the lower extremities by enabling the core muscles to activate effectively.

OBJECTIVES

The aim of this study was to investigate the effects of PBCST given as supervised or home-based on lower extremity strength and postural control in multiple sclerosis.

METHODS

Fifty individuals were enrolled and randomly allocated into two groups. Primary outcome measures were knee muscle strength and postural sway in different conditions. The supervised group received PBCST 2 days per week for 8 weeks at the clinic, and the other group performed PBCST at home. Exercises were progressed every 2 weeks in both groups.

RESULTS

Between groups, the supervised group was mostly superior to the home group (p < 0.05). A significant improvement was noted in all parameters in both groups, except some sub-parameters of postural sway in home PBCST (p < 0.05).

CONCLUSIONS

Supervised PBCST was determined to be more effective than home PBCST in improving strength, postural control, core stability, physical capacity, and fatigue. Although supervised training is the primary choice, home training can be recommended to patients who have limitations attending supervised sessions.

Postural stability is a valid and meaningful disability metric in progressive MS with potential for use in neuroprotective therapy trials

BACKGROUND

Balance impairment is observed in up to 70% of people with MS (pwMS) and worsens with disease progression. Posturography using a force platform is the current gold standard in the measurement of balance. However, posturography has not been adequately studied or widely accepted for use as a disability outcome measure for pwMS. Importantly, the recent emergence of both successful and failed neuroprotective therapy trials in progressive MS has emphasised the need for new disability outcome measures for people with progressive MS. The main objectives of this study were to evaluate the clinical validity, reliability and feasibility of posturography as a disability metric in progressive MS.

METHODS

This was a prospective cross-sectional study. We recruited 73 people with progressive MS (age 18-65 years, EDSS 3.5-6.0). Participants stood in the centre of a force platform, feet comfortably apart, under various conditions: (i) eyes open (EO), (ii) eyes closed (EC) - a single task, each lasting ninety seconds; and simultaneous EO with a cognitive test: (iii) N-Back, a three-minute test whereby participants were instructed to click the mouse when two identical letters were displayed consecutively on a screen, (iv) Sustained Attention Response Task, a five-minute test whereby participants were instructed to click the mouse for every number "1″ to "9″ except "3″ - i.e., dual-tasks. Additionally, we performed a battery of validated physical and cognitive outcome measures. Posturographic data was processed using Matlab. Statistical analysis was performed using SPSS version 26. We used multiple linear regression modelling to determine whether significant univariate correlations between posturography and clinical metrics were independent of covariates that may influence the associations seen. A two-tailed significance level of 0.05 was used.

RESULTS

Of 73 participants, mean age 52.4 (8.5) years, mean MS disease duration 13.8 (10.3) years, median EDSS 5.0 (IQR 4.0-6.0), 44 (60.4%) were female. EO-Path-Length independently predicted upper extremity function (9-Hole-Peg-Test) with a larger effect size (adjusted R²=20.0%, p = 0.001) than that for walking measures (Timed 25-Foot Walk, adjusted R²=1.6%, p = 0.01; Two-Minute Walk Test, adjusted R²=7.2%, p = 0.002), while controlling for age, disease duration, height, weight, and sex. The addition of EO-Mediolateral-Displacement to the MS Functional Composite (MSFC) created a four-component z-score that increased the variance explained for quality of life (QOL) by 62.1%. Postural stability was significantly lower with mediolateral vs anteroposterior direction of sway, removal of vision, increased body weight, male sex, and fampridine use. Postural stability improved during dual-tasks compared to EO single task. Posturography detected significant worsening of balance over a single prolonged stance.

CONCLUSION

Postural stability independently predicted a wide range of clinical metrics including upper extremity function, walking ability, cognition and QOL, therefore establishing construct and concurrent validity as a disability outcome measure for people with progressive MS. Additionally, posturography is a quantitative, non-invasive, quick-and-easy-to-administer, and highly sensitive device, demonstrating its high feasibility for use as a time- and resource-efficient disability metric in neuroprotective therapy trials for progressive MS.

Differences in the Effect of Sleep Deprivation on the Postural Stability among Men and Women

Objective: Sleepiness caused by sleep deprivation may increase the risk of injuries and damages during physical activity. Individual data so far indicate a generally better static postural stability of women regardless of sleeping conditions. The main aim of this study was to assess the impact of sleep deprivation on postural stability according to gender after 24 h of sleep deprivation. Methods: Participants included 83 students (36 men and 47 women). Postural stability was measured with eyes open and closed eyes before and after sleep deprivation. Data from posturographic platform were used to assess postural stability objectively. Results: The type of test determined the size of observed changes in postural stability. The data suggest that women are better able to cope with the effects of sleep deprivation than men. Conclusion: Postural control system is very important in sport and in physically active people. The results show that men are more sensitive to sleep deprivation than women because they had higher COP (center of pressure) values in tests. Less postural stability of the body due to sleep deprivation indicates a higher risk of injury during physical activity.

Fear of falling and falls in people with multiple sclerosis: A literature review

INTRODUCTION

Fear of falling (FOF) is a widespread problem affecting about 60% of people with multiple sclerosis (pwMS). Inflammatory lesions in the brain that are caused by the disease result in gait deficits and increase the risk of fall. Falls induce fear of falling and trigger a vicious circle, which in turn increases the likelihood of falling. Objective of this review was to provide an overview of existing research on the effects of FOF and therapy options in multiple sclerosis.

METHODS

A systematic search at Web of Science and PubMed was conducted. The search included the terms (fear of falling) OR (concern about falling) OR (fall anxiety) AND (multiple sclerosis).

RESULTS

In included studies, FOF was measured by different instruments. The Falls Efficacy Scale-International (FES-I) was the most frequently used instrument for pwMS. Patients with a higher FOF score fell more frequently, had lower walking speed, shorter stride length, larger ellipse sway area and a more severe disability. At present, therapeutic offers exist mainly in the field of physiotherapy. For reducing FOF, assisted vibration (d_z = 0.68), VR (d_z =0.87) and bicycle training (d_z = 1.23) were the most effective methods.

CONCLUSION

It is advisable to develop therapies that incorporate both physical and psychological aspects in neurorehabilitation, like in a cognitive behavioral therapy. Moreover, FOF monitoring should be integrated into the clinical routine.

Neuromuscular and Mobility Responses to a Vibration Session in Hypoxia in Multiple Sclerosis

The aim of this study was to investigate the acute effects of vibration training (WBVT) under hypoxic and normoxic conditions on the voluntary rate of force development (RFD), balance and muscle oxygen saturation (SMO₂) in persons with Multiple Sclerosis (MS). 10 participants completed the study (30% males, 44.4±7.7 years, 164.3±8.9 cm, 65.2±11.1 kg, 2.5±1.3 Expanded Disability Status Scale, 24.1±4.0 kg.m^-2 BMI). Maximal force, RFD during isometric knee extension, static balance with eyes open and closed and sit-to-stand test were evaluated before and immediately after one session of WBVT (12 60-s bout of vibration; frequency 35 Hz; amplitude 4 mm; 1-min rest intervals) under both normoxic and hypoxic conditions. In addition, SMO₂ of the gastrocnemius lateralis was assessed during each condition. No changes were found in force, static balance and sit-to-stand test. Time-to-peak RFD increased in the left leg (p=0.02) and tended to increase in the right leg (p=0.06) after the hypoxic session. SMO₂ resulted in significant increases from the initial to final intervals of the WBVT under both hypoxic and normoxic conditions (p<0.05). Increases in SMO₂ during WBVT demonstrates muscle work that may contribute to the observed muscle adaptations in long-term WBVT programs without inducing decreases in neuromuscular activation, physical function and balance within a session.

Bipedal hopping as a new measure to detect subtle sensorimotor impairment in people with multiple sclerosis

BACKGROUND

Bipedal hopping has the potential to detect subtle multiple sclerosis (MS)-related impairments, especially among patients who "pass" typical movement tests. In this narrative review, we outline the biomechanics of bipedal hopping and propose its usefulness as a novel outcome measure for people with MS having mild disability.

METHODS

We summarize articles that (1) examined the biomechanics of jumping or hopping and (2) tested the validity and/or reliability of hopping tests. We consolidated consistencies and gaps in research and opportunities for future development of the bipedal hop test.

RESULTS

Bipedal hopping requires immense power, coordination, balance, and ability to reduce co-contraction; movement components typically affected by MS. These impairments can be measured and differentiated by examining specific variables, such as hop length (power), symmetry (coordination), center of pressure (balance), and coefficient of variability (co-contraction/spasticity). Bipedal hopping challenges these aspects of movement and exposes sensorimotor impairments that may not have been apparent during walking.

CONCLUSIONS

Testing of bipedal hopping on an instrumented walkway may detect and monitor sensorimotor control in people with MS who do not currently present with clinical deficits. Early measurement is imperative for precise rehabilitation prescription to slow disability progression prior to onset of measurable gait impairment.Implications for rehabilitationJumping and hopping tests detect lower limb and balance impairments in children, athletes, and older adults.Bipedal hop test measures multiple domains: power, coordination, balance, and muscle timing.Bipedal hop test may expose subtle sensorimotor impairments in people with multiple sclerosis.Multiple variables measured can discern type of sensorimotor impairment to direct personalized rehabilitation programs.

Multiscale entropy derived complexity index analysis demonstrates significant mediolateral sway in persons with multiple sclerosis compared to healthy controls

Clinical assessment of Multiple Sclerosis relies heavily on the Expanded Disability Status Scale, a non-linear rating system based on physician assessment of disease progression and walking ability. This inherently makes this method both subjective and limited in repeatability. This study developed a technically derived outcome measure of posture to compare a cohort of Multiple Sclerosis and Control subjects during an Eyes-Open and Eyes-closed task. Analysing traditional sway parameters and a multiscale entropy derived complexity index of posturography showed a significant difference in medio-lateral sway between groups during the Eyes-Open condition. This technically derived outcome measure may be of clinical benefit in the longitudinal assessment of the functional impact of balance in MS cohorts and assist in the evaluation of pharmaceutical and rehabilitation interventions.

Structural Neural Correlates of Impaired Postural Control in People with Secondary Progressive Multiple Sclerosis

BACKGROUND

Secondary progressive multiple sclerosis (SPMS) is characterized by worsening of postural control and brain atrophy. However, little is known about postural deficits and their neuroanatomical correlates in this population. We aimed to determine the neuroanatomical correlates of postural deficits in people with SPMS and whether posture control deteriorates concomitantly with the brain and spinal cord atrophy in 2 years in SPMS.

METHODS

This study is a post hoc analysis of data from 27 people with SPMS (mean ± SE age, 58.6 ± 1.1 years). Participants had magnetic resonance imaging (MRI) of the brain and cervical spinal cord followed by sway testing using inertial sensors during standing with eyes open (EO) and eyes closed without (EC) and with (ECC) a cognitive task. Partial correlations investigated relationships between postural control and MRI measures at baseline and 2 years.

RESULTS

At baseline, sway measures were inversely related to cortical thickness and cord cross-sectional area (CSA) during the EO task but only to cord CSA with EC (P < .05). After 2 years, the percentage change in sway amplitude and dispersion during EO tasks significantly related to the percentage decline in cord CSA (P < .01).

CONCLUSIONS

Cortical and spinal cord inputs are essential for regulation of postural control during standing with EO in SPMS. Without visual input, people with SPMS preferentially rely on somatosensory inputs from the spinal cord for maintaining postural control. Postural deficits related to cord atrophy over 2 years, suggesting that postural control may be a surrogate marker of disease progression in people with SPMS.

Physical and functional aspects of persons with multiple sclerosis practicing Tai-Geiko: randomized trial

OBJECTIVES

This study aimed to verify the influence of Tai-Geiko on the physical and functional aspects of people with multiple sclerosis (MS).

METHODS

This was a parallel-group, randomized trial with two arms. People with MS were allocated to an experimental group (EG) (n=10) and control group (CG) (n=09). The participants received multidisciplinary care supervised by a physiotherapist in the Tai-Geiko exercise. Participants underwent the assessments after the intervention. The Expanded Disability Status Scale (EDSS-maximum score of 6.0), strength test (kgf) using a dynamometer, Timed Up and Go mobility test (TUG), and stabilometric balance test (Platform EMG system®) were evaluated. Demographic data were recorded, including age, sex, comorbidities, lifestyle and classification of MS. Clinical Trials (ReBeC): RBR-4sty47.

RESULTS

The EG group improved in 12 variables, and the CG improved in 3 variables. The following values were obtained for pre/postintervention, respectively: EG: lumbar force (38/52 kgf), TUG (11/9 s), locomotion velocity (519/393 ms); double task two (53/39 s); platform stabilometric trajectory: traversed get up (39/26 s) and sit (45/29 s); anteroposterior (AP) amplitude rise (11/8 cm) and sit (12.40/9.94 cm) and anteroposterior frequency rise (1.00/1.56 Hz) and sit (0.8/1.25 Hz) (p<0.05); CG: right-hand grip force (26/29 kgf); TUG (9.8 /8.7 s) and AP (11.84 /9.53 cm) stabilometric amplitude at the sitting moment (p<0.05), (3.2/5.99 Hz, p=0.01) and sit (3.47/5.01 Hz, p=0.04).

CONCLUSION

Tai-Geiko practice can be suggested as complementary exercise in the rehabilitation of persons with MS.

Balance Performance across the Lifespan Assessed by the Leonardo Mechanograph®: A Cross-Sectional Study

Reference values of sway parameters have not been published for the Leonardo mechanograph^® so far. The aim of this cross-sectional study was to determine normative values on postural control measured by the force plate Leonardo Mechanograph^® and to analyze the influence of age and sex on balance performance. A set of standardized standing positions with eyes opened (Romberg, semi-tandem, tandem, unipedal standing) was carried out. Analysis of covariance (ANCOVA) was used to detect age-and sex-related differences in center of pressure (COP) parameters (path length, velocity, elliptical area, anterior-posterior, and medio-lateral directions). Measurements were available for 570 subjects aged 20-86 years. Statistical analysis showed a high effect of age group on postural control (partial n² between 0.1 and 0.4) with a U-shaped dependency between postural control and age for all area- and path-related COP parameters, with the largest sway in the youngest (aged 20-40) and the oldest age group (aged 60-86). For velocity of COP, a linear deterioration with increasing age was found. Medio-lateral components of COP are likely to indicate the extent of postural control. Significant sex differences were not clearly supported by current findings. Age- and sex-related normative values are a useful resource for diagnostic, research, and training.

Fall Risk Prediction in Multiple Sclerosis Using Postural Sway Measures: A Machine Learning Approach

Numerous postural sway metrics have been shown to be sensitive to balance impairment and fall risk in individuals with MS. Yet, there are no guidelines concerning the most appropriate postural sway metrics to monitor impairment. This investigation implemented a machine learning approach to assess the accuracy and feature importance of various postural sway metrics to differentiate individuals with MS from healthy controls as a function of physiological fall risk. 153 participants (50 controls and 103 individuals with MS) underwent a static posturography assessment and a physiological fall risk assessment. Participants were further classified into four subgroups based on fall risk: controls, low-risk MS (n = 34), moderate-risk MS (n = 27), high-risk MS (n = 42). Twenty common sway metrics were derived following standard procedures and subsequently used to train a machine learning algorithm (random forest - RF, with 10-fold cross validation) to predict individuals' fall risk grouping. The sway-metric based RF classifier had high accuracy in discriminating controls from MS individuals (>86%). Sway sample entropy was identified as the strongest feature for classification of low-risk MS individuals from healthy controls. Whereas for all other comparisons, mediolateral sway amplitude was identified as the strongest predictor for fall risk groupings.

Normative data for the Balance Tracking System modified Clinical Test of Sensory Integration and Balance protocol

Purpose: Force plate balance testing technology has traditionally been underutilized in clinical and research settings due to the high cost and lack of portability. A relatively new force plate called the Balance Tracking System (BTrackS) has been developed to overcome these barriers. BTrackS recently implemented the modified Clinical Test of Sensory Integration and Balance (mCTSIB) as a means of evaluating various sources of sensory information for postural sway control. The present study aimed to provide much needed normative data for the BTrackS mCTSIB protocol.

Materials and methods: Data from 604 healthy adults (308 women; 296 men) between the ages of 18 and 29 years were collected according to the BTrackS mCTSIB protocol. The protocol consisted of four, 20-second static standing trials that manipulated relative contributions of the vision, proprioception and vestibular sensory systems through various eyes open/closed and foam/no foam conditions. Comparisons of men versus women and the impact of body size (ie body mass index) were determined so that relevant percentile rankings could be calculated.

Results: Analysis of variance showed an interaction between sex and task condition on the BTrackS mCTSIB (p<0.001). This interaction indicated that women outperformed men on all conditions, but especially in the fourth trial where eyes were closed and standing was done on a compliant foam surface. Percentile rankings were calculated based on sex and BTrackS mCTSIB condition. No relationship was found between BTrackS mCTSIB results and body size.

Conclusion: Normative data provided in this study are vital for establishing potential sensory feedback-based balance dysfunctions that may exist clinically or in laboratory settings. In addition, this data can aid in the tracking of changes over a rehabilitation period and/or the effectiveness of balance interventions.

Normative Data for the BTrackS Balance Test of Postural Sway: Results from 16,357 Community-Dwelling Individuals Who Were 5 to 100 Years Old

BACKGROUND

Postural sway is routinely assessed because increased postural sway is associated with poorer performance of activities of daily living, higher rates of residential care, and increased risk of falling. Force plate technology is one of the most sensitive and objective means of assessing postural sway in the clinic.

OBJECTIVE

The aim of this study was to provide the first set of normative data for the BTrackS Balance Test (BBT) of postural sway.

DESIGN

The design was descriptive and population based.

METHODS

BBT results from 16,357 community-dwelling individuals who were 5 to 100 years old were accumulated and assessed for effects of age, sex, height, and weight. Percentile rankings were calculated for significant groupings.

RESULTS

BBT results were dependent on age and sex but not height or weight. Therefore, percentile rankings were determined for male and female individuals in each age category, with no consideration of participant height or weight.

LIMITATIONS

Data were collected by third-party practitioners with various backgrounds in more than 50 locations across the United States and Canada. There was an imbalance in the sample sizes for age and sex groupings.

CONCLUSIONS

The findings of this study represent the largest normative dataset ever published for postural sway results. Normative data on the BBT can assist in determining abnormalities in postural sway, which have been linked to negative clinical outcomes.

Knee flexor strength and balance control impairment may explain declines during prolonged walking in women with mild multiple sclerosis

BACKGROUND

Physiological factors such as muscle weakness and balance could explain declines in walking distance by multiple sclerosis (MS) patients. The purpose of this study was to characterize levels and examine associations among decline in walking distance, balance and muscular strength in women with mild MS.

METHODS

Participants included 28 women with mild relapsing-remitting MS and 21 women without MS. We executed the 6-min walk test (6MWT) to verify declines in walking distance. Isokinetic knee flexion (KF) and extension (KE) muscle strength was measured using a dynamometer. Balance was quantified using a force platform, with eyes open and closed, on a rigid and foam surface.

RESULTS

The MS patients presented declines in walking, lower KF muscle strength, and worse balance than controls. KF strength and balance correlated with walking in the MS group. The KF strength explained differences between groups in walking. The KF strength and balance presented as predictors of walking slowing down in the 6MWT, in mild MS.

CONCLUSION

Women with mild MS have strength impairment of knee flexor muscles and balance control impairment that may explain walking related motor fatigability during prolonged walking.

The role of Sativex in robotic rehabilitation in individuals with multiple sclerosis: Rationale, study design, and methodology

INTRODUCTION

Currently, none of the available multiple sclerosis (MS) disease-modifying medications has been shown to stop or reverse gait disability. Recently, the nabiximols has been tested for the treatment of spasticity and walking impairment in MS. Nabiximols (trade name Sativex) is an oromucosal spray formulation containing 1:1 fixed ratio of delta-9-tetrahydrocannabinol and cannabidiol derived from cloned Cannabis sativa L. plant.

METHOD AND ANALYSIS

A single-center, prospective, parallel design, single-blind trial will be conducted at the IRCCS Neurolesi "Bonino-Pulejo" (Italy) involving MS patients affected by spasticity and undergoing a Robotic Rehabilitation training. The aim of the study is to clarify the role of Sativex coupled to a robotic neurehabilitation training in MS patients in improving motor outcomes, by means of clinical, kinematic, and neurophysiological measures. Patients will be randomly divided in 2 groups: one taking only an oral antispastic drug and the other with Sativex in add-on. After 1 month, we will evaluate the response to Sativex (responder patients' amelioration >20% at MRS score) enrolling into the study the first 20 patients with a good response to Sativex, whereas other 20 no-responder individuals will continue their antispastic drug. All the 40 subjects, were divided into 2 groups (A: Sativex + Lokomat Training, and B: other antispastic+Lokomat Training), will perform a neurorobotic-assisted gait training (each session will last at least 45 minutes, 3 times per week, for a total of 20 sessions). All the patients will undergo a complete physical and neurological examination at baseline, at the end of the robotic training (T1), and 30 days after the end of the neurorehabilitation training (T2).

Does the radiologically isolated syndrome exist? A dual-task cost pilot study

Simultaneous performance of motor and cognitive tasks may compete for common brain network resources in aging or patients with some neurological diseases, suggesting the occurrence of a cognitive-motor interference. While this phenomenon has been well described for multiple sclerosis (MS) patients, it never has been tested on asymptomatic subject with magnetic resonance imaging (MRI) findings suggestive of demyelinating disease (i.e., radiologically isolated syndrome: RIS). In this pilot study, 10 RIS subjects and 10 sex/age-matched healthy controls were tested by means of static posturography under eyes opened (single-task trial) and while performing two different cognitive tasks (semantic modified word list generation for first dual-task trial and phonemic semantic modified word list generation for second dual-task trial), to estimate the dual-task cost (DTC) of standing balance. In our sample, under cognitive interference (without any substantial differences between semantic and phonemic modified word list generation), the RIS group showed significance differences in CoP (center of pressure) total sway area, ellipse eccentricity, CoP sway path length, CoP median sway velocity along the AP (anteroposterior) axis and along the ML (mediolateral) axis, reflecting a higher negative DTC respect to healthy subjects (which have simply shown a statistical trend, failing to reach a significance, in some trials). The phenomenon of cognitive-motor interference might be unmasked by a dual-task posturography in RIS subjects, too. We hypothesize that this approach could be useful to early reveal the presence of a demyelinating disease and to reach a MS diagnosis in subjects otherwise classified as RIS.

Stooping, crouching, and standing - Characterizing balance control strategies across postures

BACKGROUND

While stooping and crouching postures are critical for many activities of daily living, little is known about the balance control mechanisms employed during these postures. Accordingly, the purpose of this study was to characterize the mechanisms driving net center of pressure (COP_Net) movement across three postures (standing, stooping, and crouching) and to investigate if control in each posture was influenced by time.

METHODS

Ten young adults performed the three postures for 60s each. Kinetic signals were collected via a force platform under each foot. To quantify mechanisms of control, correlations (Correl_LR) were calculated between the left and right COP trajectories in the anterior-posterior (AP) and medio-lateral (ML) directions. To examine the potential effects of time on balance control strategies, outcomes during the first 30s were compared to the last 30s.

RESULTS

Correl_LR values did not differ across postures (AP: p = 0.395; ML: p = 0.647). Further, there were no main effects of time on Correl_LR (AP: p = 0.976; ML: p = 0.105). A significant posture-time interaction was observed in the ML direction (p = 0.045) characterized by 35% decreases in Correl_LR over time for stooping (p = 0.022).

CONCLUSION

The dominant controllers of sway (i.e., AP: ankle plantar/dorsi flexors; ML: hip load/unload mechanism) are similar across quiet stance stooping, and crouching. Changes in ML control strategies over time suggests that fatigue could affect prolonged stooping more so than crouching or standing.