Multiple sclerosis and postural control: the role of spasticity

Neuromuscular Electrical Stimulation Does Not Influence Spinal Excitability in Multiple Sclerosis Patients

(1) Background: Neuromuscular electrical stimulation (NMES) has beneficial effects on physical functions in Multiple sclerosis (MS) patients. However, the neurophysiological mechanisms underlying these functional improvements are still unclear. This study aims at comparing acute responses in spinal excitability, as measured by soleus Hoffmann reflex (H-reflex), between MS patients and healthy individuals, under three experimental conditions involving the ankle planta flexor muscles: (1) passive NMES (pNMES); (2) NMES superimposed onto isometric voluntary contraction (NMES+); and (3) isometric voluntary contraction (ISO). (2) Methods: In total, 20 MS patients (MS) and 20 healthy individuals as the control group (CG) took part in a single experimental session. Under each condition, participants performed 15 repetitions of 6 s at 20% of maximal voluntary isometric contraction, with 6 s of recovery between repetitions. Before and after each condition, H-reflex amplitudes were recorded. (3) Results: In MS, H-reflex amplitude did not change under any experimental condition (ISO: p = 0.506; pNMES: p = 0.068; NMES+: p = 0.126). In CG, H-reflex amplitude significantly increased under NMES+ (p = 0.01), decreased under pNMES (p < 0.000) and was unaltered under ISO (p = 0.829). (4) Conclusions: The different H-reflex responses between MS and CG might reflect a reduced ability of MS patients in modulating spinal excitability.

The effect of fatigue on postural control in individuals with multiple sclerosis: a systematic review

BACKGROUND

Fatigue is the most disabling symptom for individuals with multiple sclerosis (MS), which can significantly affect postural control (PC) by impairing the ability of the central nervous system to modulate sensory inputs and coordinate motor responses. This systematic review aimed to investigate the effect of fatigue on PC in individuals with MS..

METHODS

This systematic review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and registered in PROSPERO with ID CRD42022376262. A systematic search was performed in the Web of Science, PubMed, Scopus, and Google Scholar until January 2023, and a manual search was performed using the reference lists of included studies. Two authors independently selected the studies, extracted data, and evaluated their methodological quality using the Downs and Black checklist. The process was later discussed with a third author..

RESULTS

Five studies were included in this review, of which consistent evidence investigating a direct relationship between fatigue and PC in individuals with MS. All the studies reported negative effects on PC. Four studies employed walking tests as their primary protocol for inducing fatigue, while one study implemented a strength testing protocol for both legs, serving as a fatigue-inducing activity.

CONCLUSIONS

The evidence suggests that individuals with MS may experience PC deficits due to fatigue. However, the present body of literature exhibits limitations regarding its quality and methodology. Gender differences, balance, fatigue task, and muscle function are essential factors that need to be considered when investigating the relationship between fatigue and PC deficits in MS. Further high-quality research is necessary to comprehend the complex interplay between MS-related fatigue and PC deficits after physical activity.

Training-dependent plasticity and far transfer effect enhanced by Bobath rehabilitation in Multiple Sclerosis

BACKGROUND

Multiple Sclerosis (MS) is a disease that often results in motor and/or cognitive disability. Despite the increasing availability of effective drug therapies, rehabilitation is very important means of counteracting the progression of disability and improving physical function, impacting social participation and improving quality of life. Several rehabilitation approaches can be used in the context of neuro-motor rehabilitation, but there is insufficient evidence for them in the literature.

OBJECTIVES

This study has the twofold purpose of: (i) investigate whether rehabilitation according to Bobath Concept can improve balance and some aspects of cognitive function in MS patients; (ii) explore whether the ability to improve postural control, an indirect index of adaptive neuroplasticity, is preserved in MS patients and whether it can be improved with rehabilitation.

METHOD

This is an independent wait-listed study. Forty people with MS (pwMS) were enrolled: patients in the Bobath group underwent 8 weeks of rehabilitation according to the Bobath Concept. For aim 1, pwMS were assessed at baseline (T0), at the end of the 8 weeks of treatment (T1) and after 8 weeks of observation (T2) with motor and cognitive scales. For aim 2, the same 40 pwMS were matched with healthy controls and were subjected to a postural learning task using the force platform at T0, T1 and T2.

RESULTS

Patients in Bobath group scored better on balance and cognitive function at T1, but this improvement was not maintained at T2. All patients were less accurate than controls in the postural learning task at each assessment; however, patients also demonstrated an increase in accuracy after training, similar to that of healthy controls. The learning curve was better for patients randomized to the active group than the waitlist at T1 time, but this advantage was not maintained at the T2 assessment.

CONCLUSION

In light of the results, this study supports the use of rehabilitation according to Bobath Concept to improve balance control and some executive functions in MS. Despite worse baseline performance, pwMS were able to learn a postural control task on par with healthy controls. Also, supports the hypothesis that adaptive plasticity is preserved despite MS and can be promoted by rehabilitation.

Neurorehabilitation in Multiple Sclerosis-A Review of Present Approaches and Future Considerations

Multiple sclerosis is an increasingly prevalent disease, representing the leading cause of non-traumatic neurological disease in Europe and North America. The most common symptoms include gait deficits, balance and coordination impairments, fatigue, spasticity, dysphagia and an overactive bladder. Neurorehabilitation therapeutic approaches aim to alleviate symptoms and improve the quality of life through promoting positive immunological transformations and neuroplasticity. The purpose of this study is to evaluate the current treatments for the most debilitating symptoms in multiple sclerosis, identify areas for future improvement, and provide a reference guide for practitioners in the field. It analyzes the most cited procedures currently in use for the management of a number of symptoms affecting the majority of patients with multiple sclerosis, from different training routines to cognitive rehabilitation and therapies using physical agents, such as electrostimulation, hydrotherapy, cryotherapy and electromagnetic fields. Furthermore, it investigates the quality of evidence for the aforementioned therapies and the different tests applied in practice to assess their utility. Lastly, the study looks at potential future candidates for the treatment and evaluation of patients with multiple sclerosis and the supposed benefits they could bring in clinical settings.

Postural Sway in Parkinson's Disease and Multiple Sclerosis Patients During Tasks With Different Complexity

Neurological diseases are associated with static postural instability. Differences in postural sway between neurological diseases could include "conceptual" information about how certain symptoms affect static postural stability. This information might have the potential to become a helpful aid during the process of finding the most appropriate treatment and training program. Therefore, this study investigated static postural sway performance of Parkinson's disease (PD) and multiple sclerosis (MS) patients, as well as of a cohort of healthy adults. Three increasingly difficult static postural tasks were performed, in order to determine whether the postural strategies of the two disease groups differ in response to the increased complexity of the balance task. Participants had to perform three stance tasks (side-by-side, semi-tandem and tandem stance) and maintain these positions for 10 s. Seven static sway parameters were extracted from an inertial measurement unit that participants wore on the lower back. Data of 47 healthy adults, 14 PD patients and 8 MS patients were analyzed. Both healthy adults and MS patients showed a substantial increase in several static sway parameters with increasingly complex stance tasks, whereas PD patients did not. In the MS patients, the observed substantial change was driven by large increases from semi-tandem and tandem stance. This study revealed differences in static sway adaptations between PD and MS patients to increasingly complex stance tasks. Therefore, PD and MS patients might require different training programs to improve their static postural stability. Moreover, this study indicates, at least indirectly, that rigidity/bradykinesia and spasticity lead to different adaptive processes in static sway.

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.

COVID-19 and Postural Control—A Stabilographic Study Using Rambling-Trembling Decomposition Method

Background and Objectives: Some respiratory viruses demonstrate neurotropic capacities. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has recently taken over the globe, causing coronavirus disease 2019 (COVID-19). The aim of the study was to evaluate the impact of COVID-19 on postural control in subjects who have recently recovered from the infection. Materials and Methods: Thirty-three convalescents who underwent COVID-19 within the preceding 2–4 weeks, and 35 healthy controls were enrolled. The ground reaction forces were registered with the use of a force platform during quiet standing. The analysis of the resultant center of foot pressure (COP) decomposed into rambling (RAMB) and trembling (TREMB) and sample entropy was conducted. Results: Range of TREMB was significantly increased in subjects who experienced anosmia/hyposmia during COVID-19 when the measurement was performed with closed eyes (p = 0.03). In addition, subjects who reported dyspnea during COVID-19 demonstrated significant increase of length and velocity of COP (p < 0.001), RAMB (p < 0.001), and TREMB (p < 0.001), indicating substantial changes in postural control. Conclusions: Subjects who had experienced olfactory dysfunction or respiratory distress during COVID-19 demonstrate symptoms of balance deficits after COVID-19 recovery, and the analysis using rambling-trembling decomposition method might point at less efficient peripheral control. Monitoring for neurological sequelae of COVID-19 should be considered.

Effect of dynamic neuromuscular stabilization on balance and trunk function in people with multiple sclerosis: protocol for a randomized control trial

Background

Multiple sclerosis is a chronic and disabling neurological disease among young people. One of the major complaints in patients with multiple sclerosis (PWMS) is falling. There are a number of factors that risk factors for falling, including balance disorder and spasticity. Core stability (CS) exercises such as trunk muscle strengthening exercises can improve balance and mobility and reduce falling. Dynamic neuromuscular stabilization (DNS) exercise is a new functional rehabilitation strategy that optimizes motor function based on the principles of developmental kinesiology. This trial will evaluate the effectiveness of DNS in comparison to CS on balance, spasticity, and falling in PWMS.

Methods

A total of 64 PWMS, between 30 and 50 years old and expanded disability status scale (EDSS) between 2 to 5, will be recruited from neurophysiotherapy clinic, Faculty of Rehabilitation Sciences, Iran University of Medical Sciences to participate in this 2-armed parallel study. Participants will be randomly divided into two groups to receive CS exercise or DNS exercise. All participants will receive exercise treatment for 15 sessions during a period of 5 weeks (3 sessions per week). Primary outcome measures will be balance. Falling rate, fear of falling, patient mobility, as well as spasticity, will be measured as secondary outcomes. All outcome measures will be measured at baseline, the day after the completion of the 15th session, and after 17 weeks.

Discussion

Dynamic neurostabilization exercises utilize the subconscious stimulation of special zones to reflexively mediate the diaphragm and other core stabilization muscles, which is extremely effective for individuals with reduced somatosensory or movement awareness. Findings from the proposed study are expected to benefit the knowledge base of the physiotherapist, and it can be a good alternative for the rehabilitation program and even reduce medication use in patients with multiple sclerosis. These exercises are easy to understand and applicable for these patients and their partners as well.

Trial registration

The trial was registered in the Iran registry organization with code IRCT20140222016680N5 and was approved on April 7^th, 2020. Address: IRCT administration team, Central Library Building, Iran University Campus, Hemmat Freeway, next to Milad tower, Tehran, Iran. postal code:14496-14535.

Simplified stance limb kinetics patterns revealed during gait initiation in early stage of multiple sclerosis

BACKGROUND

Although patients with an early stage of Multiple Sclerosis (MS) commonly complain about balance and gait impairments, their troubles remain misunderstood. The objective was to compare body kinematics and lower limb kinetics during gait initiation between patients with MS with an EDSS score ≤ 4 and healthy participants.

METHODS

Sixteen patients with MS with a median EDSS score of 2.5 [0-4] and disease duration of 7.4 ± 4.2 years, as well as 16 healthy participants were included, and 3-D motion analysis was performed during gait initiation to calculate spatiotemporal, kinematic and kinetic parameters.

FINDINGS

The center of pressure position at the beginning of the gait initiation was more anterior (p = 0.02) in patients with MS than healthy participants. The kinetic parameters of the stance limb were highly affected in patients with MS compared to healthy participants during gait initiation. The net muscular moments for each joint were significantly different during the anticipatory postural adjustment phase with smoother variations for patients with MS compared to healthy participants.

INTERPRETATION

Early stage MS strongly affects the motor modulation of stance limb kinetics during the anticipatory postural adjustment of gait initiation, without alteration of the execution phase. The net muscular moments are sensitive in detecting unobservable balance impairments and can be used to assess disease progression at the early stage. These results suggest that early rehabilitation programs aimed at improving motor modulation and flexibility in gait initiation should be implemented.

Comparison of efficacy of vestibular rehabilitation and noisy galvanic vestibular stimulation to improve dizziness and balance in patients with multiple sclerosis

BACKGROUND

Dizziness and imbalance are common symptoms in patients with multiple sclerosis (PwMS), and rehabilitation interventions varying greatly in effectiveness.

OBJECTIVE

To compare the effectiveness of vestibular rehabilitation therapy (VRT) and noisy galvanic vestibular stimulation (nGVS) on dizziness and balance in PwMS.

METHODS

This was a single-blind, randomized controlled trial. Twenty-four PwMS were randomly divided into groups of VRT, nGVS, and Control. The VRT and the nGVS groups underwent the intervention program. The patients were assessed with the composite score in anteroposterior and lateral directions (CS AP and LAT) obtained by sensory organization test (SOT), Dizziness Handicap Inventory (DHI), and Activities-Specific Balance Confidence Scale (ABC).

RESULTS

The VRT group showed greater improvements in CS AP and LAT, DHI total score, and ABC total score compared with the nGVS group and the control group. No significant difference was found between the nGVS group and the control group. These results were approximately stable at the 4-week follow-up.

CONCLUSIONS

These findings provided evidence for effectiveness of the VRT in improvement of dizziness and balance in PwMS. These improvements were not associated with the nGVS. Further studies are needed to assess the effectiveness of the nGVS on dizziness and balance in PwMS.

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.

Effects of low vs. high frequency local vibration on mild-moderate muscle spasticity: Ultrasonographical and functional evaluation in patients with multiple sclerosis

BACKGROUND

Local vibration (LV) is a physiotherapy application that aims to reduce spasticity. The study aimed to compare the effects of 50 Hz vs. 100 Hz LV on mild-moderate spasticity, functional performance and muscle architecture.

METHODS

Thirty-three patients were randomly divided into three groups: 50 Hz LV group, 100 Hz LV group and the control group. Physical therapy was applied for one hour a day, three days a week, for a total of eight weeks. LV was applied to the right and left medial gastrocnemius muscles for five minutes. Clinical (spasticity, ankle joint position sense, balance, gait) and ultrasonographic (gastrocnemius fascicle length and pennation angle) measurements were performed before and after treatment.

RESULTS

The study was completed with 27 patients. The decrease in spasticity and the increase in fascicle length were found to be statistically significant in the 50 Hz group (both p<0.05). Ankle joint position sense, single-leg stance time, limits of stability/postural sway range in the medio-lateral direction significantly improved in the vibration treatment groups (all p<0.05). The antero-posterior limits of stability and postural sway showed significant improvement in all groups (all p<0.05). While the 50 Hz group showed significant improvement for all walking parameters; velocity, step length and base of support values improved in the 100 Hz group (all p<0.05). The exercise group showed significant improvement only for single support and stance phase percentages of the gait cycle (both p<0.05). According to between group comparisons, significant difference was found only in medio-lateral limits of stabillity (p<0.05). Medio-lateral limits of stabillity scores were better for the 50 Hz group than the 100 Hz and exercise group.

CONCLUSION

Our findings show that LV does not have any substantial effect except for medio-lateral limits of stability.

CLINICAL TRIAL NUMBER

NCT04192786.

Role of Spasticity Severity in the Balance of Post-stroke Patients

Background: Lower limb spasticity after stroke is common that can affect the balance, increase the risk of falling, and reduces the quality of life. Objective: First, evaluate the effects of spasticity severity of ankle plantar flexors on balance of patients after stroke. Second, to determine the relationship between the spasticity severity with ankle proprioception, passive ankle dorsiflexion range of motion (ROM), and balance confidence. Methods: Twenty-eight patients with stroke based on the Modified Modified Ashworth Scale (MMAS) were divided into two groups: High Spasticity Group (HSG) (MMAS > 2) (n = 14) or a Low Spasticity Group (LSG) (MMAS ≤ 2) (n = 14). The MMAS scores, Activities-Specific Balance Confidence Questionnaire, postural sway of both affected and non-affected limbs under the eyes open and eyes closed conditions, timed up and go (TUG) test, passive ankle dorsiflexion ROM, and ankle joint proprioception were measured. Results: The ankle joint proprioception was significantly better in the LSG compared to the HSG (p = 0.01). No significant differences were found between the LSG and HSG on all other outcome measures. There were no significant relationships between the spasticity severity and passive ankle dorsiflexion ROM, and balance confidence. Conclusion: The severity of ankle plantar flexor spasticity had no effects on balance of patients with stroke. However, the ankle joint proprioception was better in patients with low spasticity. Our findings suggest that the balance is affected regardless of the severity of the ankle plantar flexor spasticity in this group of participants with stroke.

Advanced characterization of static postural control dysfunction in persons with multiple sclerosis and associated neural mechanisms

BACKGROUND

Multiple sclerosis (MS) is an autoimmune-based chronic inflammatory disease characterized by the neurodegeneration of the central nervous system and produces postural dysfunction. Quiet or static standing is a complex task carried out through afferent sensory inputs and efferent postural corrective outputs. Currently the mechanisms underlying these outputs remain largely unknown.

RESEARCH QUESTION

Assess the relationship between multi-dimensional measures of postural control and microstructural integrity of the cortical sensorimotor pathway (CSP) in persons with MS (PwMS) and neurotypical adults.

METHODS

Postural control performance was assessed by both overall and directional time-to-boundary measures across four manipulated sensory stance conditions (eyes open/closed; stance firm/foam) in twenty-nine neurotypical and twenty-seven PwMS. These postural outcomes were evaluated with mixed-model repeated measures analysis of variance across group (MS and control) and stance condition. Postural performance was also correlated with magnetic resonance imaging diffusion tensor-derived measures of microstructural integrity of the CSP.

RESULTS

PwMS displayed significantly (p =  0.026) worse anterior-posterior postural control compared to their neurotypical counterparts across sensory testing conditions and poorer CSP microstructural integrity in comparison to neurotypical adults (p =  0.008). Additionally, PwMS displayed a significant association (2D (rho = -0.384, p =  0.048), AP (rho = -0.355, p =  0.035), and ML (rho = -0.365, p =  0.030) between integrity of the CSP and postural control performance during proprioceptive-based balance, such that those with worse cortical structure had poorer balance control.

SIGNIFICANCE

This is the first study to establish connections between the microstructural integrity of the CSP and multi-dimensional postural control performance. Results indicate that a reduction in the CSP microstructural integrity is associated with poorer postural control in PwMS. These outcomes identify neural underpinnings of postural control dysfunction in PwMS and provide new avenues for evaluating the efficacy of postural rehabilitation strategies in PwMS that express proprioceptive-based postural deficits.

Comparing the effects of vestibular rehabilitation with and without lavender oil scents as an olfactory stimulus on balance, fear of falling down and activities of daily living of people with multiple sclerosis: a randomized clinical trial

PURPOSE

To evaluate the effect of using lavender oil as an olfactory stimulus with vestibular rehabilitation (VR) on balance, fear of falling down, and activities of daily living of people with multiple sclerosis.

METHODS

Forty participants were randomly assigned into experimental and control groups. The experimental group did the VR exercises while smelling the lavender oil scents. The control group did the VR exercises without it. Both groups did the exercises in ten 45-min sessions. We assessed the participants with the timed up and go (TUG) test, Berg balance scale (BBS), fall efficacy scale - international (FES-I), and the 29-item multiple sclerosis impact scale (MSIS-29). We did the tests at the baseline and after the last exercise session.

RESULTS

The experimental group performed significantly better in the BBS (p = 0.007), TUG (p = 0.045), and FES-I (p = 0.016) tests as well as in the MSIS-29's psychological subscale (p = 0.034) than did the control group.

CONCLUSIONS

Using lavender oil as olfactory stimulus while doing the VR exercises can improve balance and reduce fear of falling down compared to doing the VR exercises without it in people with multiple sclerosis.Implications for rehabilitationIt seems that using lavender oil, as an olfactory stimulus, while doing vestibular rehabilitation exercises can improve balance and reduce fear of falling down in people with multiple sclerosis compared to doing the vestibular rehabilitation exercises without it.This treatment significantly alleviates the psychological effects of multiple sclerosis on daily life such as sleeping problems, feeling unwell, anxious, tense, depressed, etc.

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.

The inter- and intra-rater reliability of Modified Tardieu Scale in assessing spasticity of knee extensors in patients with multiple sclerosis

INTRODUCTION

Spasticity is one of the most common and disabling symptoms in Multiple sclerosis (MS). The is a clinical tool for assessing spasticity. This study aimed to investigate the inter- and intra-rater reliability of the modified Tardieu scale for assessing knee extensors spasticity in MS patients.

METHODS

Twenty-six patients with MS (12 females and 14 males) with a mean age of 40 ± 11.39 years participated in this study. The extensor muscles of both knees were evaluated using the MTS in two sessions. At first session, two examiners randomly assessed the knee extensor spasticity to study the inter-rater reliability and 3-4 days later the first examiner assessed the patients again, to determine intra-rater reliability. Intra-class Correlation Coefficient (ICC) analysis, two-way random effect model was used to determine the reliability of various components of the modified Tardieu scale.

RESULTS

The inter-rater reliability for quality of muscle reaction of knee extensor muscles was very good (ICC = 0.89) and for the difference between the angle of muscle response (R1) and full range(R2) of movement (R2- R1), as spasticity intensity criterion, was good (ICC = 0.73). ICC values for R2-R1 and muscle response quality assessments by one rater were 0.73 and 0.82, respectively.

CONCLUSION

The findings of the current study showed that the MTS has good to very good inter- and intra-rater reliability for assessing knee extensors spasticity in MS patients.

Relationship between soleus H-reflex asymmetry and postural control in multiple sclerosis

Background: Impaired postural control is a common symptom in people with multiple sclerosis. Multiple sclerosis frequently presents with asymmetric motor involvement. One measurement yet to be evaluated for asymmetry in people with multiple sclerosis is the soleus Hoffmann reflex. Purpose: To measure the soleus Hoffmann reflex between limbs and correlate reflex asymmetry with postural control.Material and methods: 16 participants completed four sessions of Hoffmann reflex testing and one session of balance testing.Results: Multiple sclerosis participants had significantly greater reflex asymmetry (p = 0.01). The multiple sclerosis group had a significantly lower overall sensory organization testing composite score (p < 0.05), indicating sensory interpretation conflict that resulted in greater postural instability. Multiple sclerosis participants produced a significantly shorter endpoint and maximum excursion (p < 0.01) during limits of stability testing. Hoffmann reflex asymmetry was negatively related to forward endpoint excursion (p < 0.05), maximum excursion (p [Formula: see text] 0.01).Conclusions: Multiple sclerosis participants had greater soleus Hoffmann reflex asymmetry, which appears to significantly influence forward postural control.Implications for rehabilitationSoleus Hoffmann reflex asymmetry appears to influence postural stability.The soleus Hoffmann reflex is capable of adapting to different modes of exercise; therefore, to reduce H-reflex asymmetry it is recommended to individualize physical rehabilitative programming.Assessing the soleus Hoffmann reflex in people with multiple sclerosis during health screenings could be of use to clinical and rehabilitative practitioners.

Relative importance of vision and proprioception in maintaining standing balance in people with multiple sclerosis

BACKGROUND

Balance impairment is common and a risk factor of falls in people with multiple sclerosis (MS). The purpose of this study was to evaluate the relative importance between vision and proprioception in maintaining standing body balance among individuals with MS compared with healthy individuals.

METHODS

Thirty people with MS (the mean ± standard deviation of the Patient Determined Disability Steps: 3.62 ± 1.67 out of 8) and 25 healthy adults participated in this cross-sectional study. They underwent a static posturography test, consisting of three sensory feedback conditions: eyes open on a firm surface, eyes closed on a firm surface, and eyes open on a compliant surface. Their standing balance performance, quantified by the 95% confidence ellipse area and the total length of the center of pressure trajectory during each sensory condition, was calculated based on the ground reaction force data. The Romberg's quotient (the ratio of the center of pressure measurements on the firm surface between eyes open and eyes closed conditions) and proprioception quotient (the ratio of the center of pressure measurements with eyes open between firm and compliant standing surfaces) were calculated and compared between groups.

RESULTS

Persons with MS demonstrated significantly larger postural sway under all three sensory conditions than their healthy counterparts. The reliance on the vision and proprioception systems in maintaining body balance was greater among people with MS compared to healthy adults. Both groups similarly relied more on the proprioceptive input to keep body balance than on the vision.

CONCLUSIONS

Like healthy individuals, persons with MS rely more on proprioception to maintain body balance than vision. Our findings could provide preliminary reference for optimizing balance improving programs aimed at person with MS.

Contractile properties of superficial skeletal muscle affect postural control in healthy young adults: A test of the rambling and trembling hypothesis

The rambling and trembling analysis separates the center of pressure (COP) fluctuations into two components: rambling (supraspinal contribution) and trembling (muscle stiffness / reflexive properties contribution). We examined whether the trembling component is correlated to the contractile properties (muscle stiffness and contraction time) of lower limb superficial skeletal muscles to experimentally test the rambling and trembling hypothesis. We hypothesized that muscle stiffness and contraction time, would be: (a) more correlated with; and (b) have a greater impact on the trembling component compared to the rambling component. Thirty-two healthy young adults were recruited for the study and tensiomyography was used to assess mechanical muscle responses to a single electrical stimulus to calculate muscle stiffness and contraction time based on radial muscle belly displacement measurements of lower limb muscles unilaterally. Moreover, upright postural control was assessed using a force plate to record ground reaction forces and moments and calculate the COP fluctuations during two 30 seconds trials. From the COP fluctuations, rambling and trembling time series were extracted, and all fluctuation time series were described using a number of different time-domain and frequency-domain parameters in both the anterior-posterior and medial-lateral directions. Our results demonstrated that both muscle stiffness and contraction time were moderately correlated with time-domain and frequency-domain parameters of the trembling component, as compared with those of the rambling component which was not as well correlated. Moreover, they also predicted the trembling component better. Overall, these results imply that postural control during quiet stance is, in part, related to intrinsic muscle stiffness in the lower extremities. Moreover, we showed that the rambling and trembling hypothesis is effective in separating postural sway fluctuations during upright posture to extract the contributions of muscle stiffness / reflexive properties (trembling), and likely the supraspinal contribution (rambling).

Assessment and Measurement of Spasticity in MS: State of the Evidence

PURPOSE OF REVIEW

The purpose of this review is to familiarize the reader with assessments and measurement of spasticity in people with multiple sclerosis (MS). Spasticity affects 60-84% of people with MS, worsening as disability worsens and impacting activity, participation, and quality of life. Spasticity manifests in many ways, including spasms, resistance to passive stretch, pain, and perception of tightness, and can affect muscles throughout the body, making assessment and quantification of spasticity challenging but important. Assessment tools include those quantified by clinicians, instrumentation, and patients.

RECENT FINDINGS

Most tools for measuring spasticity are based on clinician scoring, were developed many years ago, and have undergone minimal recent advances. More recent developments are patient-reported outcome measures for spasticity, including the Numeric Rating Scale for Spasticity (NRS-S) and the disease-specific Multiple Sclerosis Spasticity Scale-88 (MSSS), and, most recently, imaging through elastography. MS-related spasticity is common and often disabling. There are various spasticity measurement tools available, each with advantages and limitations. Newer tools are likely to be developed as our understanding of spasticity in MS grows.

Effectiveness of Physiotherapy Interventions on Spasticity in People With Multiple Sclerosis: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of the study was to examine the effectiveness of physiotherapy (PT) interventions on spasticity in people with multiple sclerosis.

DESIGN

A systematic search was performed using PRISMA guidance. Studies evaluate the effect of PT interventions on spasticity were included. People with multiple sclerosis, spasticity, disability and PT interventions characteristics were extracted in included studies. Level of evidence was synthesized by the Grade of Recommendation, Assessment, Development and Evaluation approach. Meta-analyses were performed by calculating Hedges g at 95% confidence interval.

RESULTS

A total of 29 studies were included in the review, and 25 were included in the meta-analyses. The included PT interventions were exercise therapy, electrical stimulation, radial shock wave therapy, vibration, and standing. The review and meta-analyses showed different evidences of benefits and nonbenefits for PT interventions on some spasticity outcomes. The best quality evidences were for beneficial effects of exercise therapy especially robot gait training and outpatient exercise programs on self-perceived spasticity and muscle tone respectively. The review results were positive regarding the acute effects, follow-up measurements, safety, progressive MS, and nonambulatory people with multiple sclerosis. The included articles were heterogeneous and badly reported in PT interventions and people with multiple sclerosis characteristics.

CONCLUSIONS

Physiotherapy interventions can be a safe and beneficial option for spasticity in people with multiple sclerosis. No firm conclusion can be drawn on overall spasticity. Further researches in different spasticity aspects are needed.

Spasticity, gait, and balance in patients with multiple sclerosis: A cross-sectional study

OBJECTIVE

More than 80% of people with multiple sclerosis (MS) are affected by spasticity. Spasticity is known to reduce quality of life and contribute to additional symptoms, such as pain and reduced mobility, but the association between spasticity, balance, and mobility has not yet been established. Our aim was to examine whether a relationship exists between spasticity in the lower limbs, balance, and gait, as well as to explore the involvement of different muscle groups.

METHODS

This study employed a cross-sectional design. Thirty patients with MS were included. The Modified Ashworth Scale (MAS) was used to examine spasticity in the ankle plantar flexors, knee extensors, and hip adductors. Balance was measured using the Mini-Balance Evaluation Systems Test, and gait with the 2-Minute Walk Test. The participants were tested once with no additional follow-up. Spearman's correlation, recursive partitioning, and linear regression analyses were used to explore the association.

RESULTS

A significant correlation between gait distance and spasticity in the ankle plantar flexors (ρ = -.69, p < .001) and knee extensors (ρ = -.45, p = .012) was observed. Balance significantly correlated with spasticity in ankle plantar flexors (ρ = -.69, p < .001), knee extensors (ρ = -.52, p = .003), and hip adductors (ρ = -.5, p = .005). The relationship between spasticity in ankle plantar flexors and hip adductors was significant, even from low levels of spasticity, whereas MAS score ≥ 2 was clinically correlated with a decrease in gait and balance function. Adjustments for sex, age, or years since diagnosis had only minor impact on the results.

CONCLUSIONS

This study indicates that spasticity in the lower limbs is clinically significantly associated with mobility in people with MS.

Visual but not verbal working memory interferes with balance in patients after optic neuritis suggestive of multiple sclerosis

BACKGROUND

Subtle cognitive deficits are present in almost half of the patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). Similarly, subtle balance deficits can be detected at the earliest stages of the disease. To assess cognitive-motor interference (CMI) in nondisabled CIS patients, we studied postural performance using dual task paradigm in CIS patients presenting with optic neuritis.

METHODS

We prospectively included 20 patients with visual acuity of 0.8 or more within the 3 months from unilateral ON. We also included 20 age, weight, height and education matched healthy subjects. Baseline cognitive performance of the patients was assessed using neuropsychological tests. Balance was studied by posturography (Po) and center of pressure (CoP) measures (maximal medio-lateral, maximal antero-posterior amplitudes, maximal CoP velocity and total CoP path. CMI between static balance and WM was investigated using a dual-task paradigm in three conditions: Po alone, Po+Brooks' visual working memory (WM) task and Po+2-back verbal WM task.

RESULTS

The two most commonly affected cognitive domains in the patients were attention (52% of the patients) and executive functions (45% of the patients). Static balance as measured by higher maximal CoP velocity while standing alone (p = 0.02) was impaired in patients. Significantly lower maximal m-l CoP amplitude (p = 0.01) and total CoP path (p = 0.004) in the Po + Brooks' task condition compared to Po alone were observed in the group of ON patients but not in healthy subjects. The cost of dualtasking was highest in the ON patients under Po + Brooks' task (p = 0.04 for the total CoP path parameter).

CONCLUSION

Static balance and cognition are impaired in the earliest MS. CMI between static balance and working memory is higher in the patients and while loading visual working memory. Dual-task paradigms should be used in rehabilitation programmes for patients at the very beginning of the disease.

Whole-body vibration impedes the deterioration of postural control in patients with multiple sclerosis

OBJECTIVE

The current study aimed to investigate if whole-body vibration (WBV) might attenuate the processing functional and neuromuscular degeneration of postural control in patients with MS.

DESIGN

Performance in postural control was assessed before and after 6 weeks of a control (CON) and a WBV intervention period.

SETTING

Laboratory at the University of Freiburg & home-based training PARTICIPANTS: Out of 29 interested participants, 15 subjects with severe MS fit inclusion criteria.

MAIN OUTCOME MEASURES

Centre of pressure displacement (COP), muscle activity and co-contraction indices of m. soleus (SOL), gastrocnemius medialis (GM), tibialis anterior (TA), biceps (BF) and rectus femoris (RF) as well as SOL H/M-ratios.

RESULTS

After CON, COP was significantly enhanced with reduced muscle activity in RF and diminished shank muscle co-contraction. After WBV, no changes were observed in COP and neuromuscular control. However, over time, TA activity was reduced, but with no changes in muscle activation of SOL, GM and BF or H/M-ratios.

CONCLUSIONS

After CON, MS patients experienced substantial deteriorations in postural control which have previously been associated with greater postural instability. No further disease-associated deteriorations were observed following the intervention. Thus, WBV might alleviate neurodegeneration of postural control in people with MS.

The Short-Term Effect of Slope Walking on Soleus H-Reflexes in People with Multiple Sclerosis

Downslope walking (DSW) causes H-reflex depression in healthy adults, and thus may hold promise for inducing spinal reflex plasticity in people with Multiple Sclerosis (PwMS). The study purpose was to test the hypothesis that DSW will cause acute depression of spinal excitability in PwMS. Soleus H-reflexes were measured in PwMS (n = 18) before and after 20 min of treadmill walking during three visits. Participants walked on a different slope each visit [level: 0% level walking (LW), upslope: +7.5% treadmill walking with an upslope (USW) or downslope: -7.5% (DSW)]. The soleus H_max/M_max ratio was used to measure spinal excitability. Heart rate and ratings of perceived exertion (RPE) were measured during walking. DSW induced the largest change in spinal excitability (a 26.7% reduction in soleus H_max/M_max (p = 0.001)), although LW also reduced H_max/M_max (-5.3%, p = 0.05). Heart rate (p < 0.001) was lowest for DSW, and RPE for DSW did not exceed "Fairly light". DSW evokes short-term spinal plasticity in PwMS, while requiring no greater effort than LW. Our results suggest that PwMS retain the capacity for DSW-induced short-term spinal reflex modulation previously found in healthy adults. These results may provide a foundation for further investigation of long-term effects of DSW on spinal reflex plasticity and functional ability in PwMS.

Postural control deficits in people with Multiple Sclerosis: A systematic review and meta-analysis

BACKGROUND

Multiple sclerosis (MS) is a neurological condition that can affect the postural stability of the individual and predispose falls in this population.

METHODS

A systematic literature search identified case-control studies investigating differences in postural control across a diversity of task conditions, with the exception of gait, between people with MS and healthy controls. Meta-analysis was conducted where a variable was presented by four or more studies.

RESULTS

Forty-three studies of people with a mean Expanded Disability Status Scale (EDSS) of 1.0 to 6.0 were included. Seven conditions of assessment and 105 individual measurement variables relating to postural control were included. Quiet stance was the only condition (11 studies) possessing sufficient data to contribute to meta-analysis in terms of centre of pressure path length (SMD = 1.04, 95% CI {0.86-1.22}, p < 0.001), medio-lateral velocity (SMD = 1.35, 95% CI {0.77-1.92}, p < 0.001) and 95% confidence ellipse (SMD = 0.83 95% CI {0.59-1.08}, p < 0.001).

RESULTS

indicate that regardless of task complexity or sensory condition, people with MS display considerable deficits in postural control in comparison to healthy controls.

CONCLUSIONS

The large number of variables and lack of standardisation of reporting makes data synthesis challenging, however, people with MS display considerable deficits in postural control compared to healthy controls regardless of task condition or complexity.

Impact of Spasticity on Balance Control during Quiet Standing in Persons after Stroke

Background

Balance impairments, falls, and spasticity are common after stroke, but the effect of spasticity on balance control after stroke is not well understood.

Methods

In this cross-sectional study, twenty-seven participants with stroke were divided into two groups, based on ankle plantar flexor spasticity level. Fifteen individuals with high spasticity (Modified Ashworth Scale (MAS) score of ≥2) and 12 individuals with low spasticity (MAS score <2) completed quiet standing trials with eyes open and closed conditions. Balance control measures included centre of pressure (COP) root mean square (RMS), COP velocity, and COP mean power frequency (MPF) in anterior-posterior and mediolateral (ML) directions. Trunk sway was estimated using a wearable inertial measurement unit to measure trunk angle, trunk velocity, and trunk velocity frequency amplitude in pitch and roll directions.

Results

The high spasticity group demonstrated greater ML COP velocity, trunk roll velocity, trunk roll velocity frequency amplitude at 3.7 Hz, and trunk roll velocity frequency amplitude at 4.9 Hz, particularly in the eyes closed condition (spasticity by vision interaction). ML COP MPF was greater in the high spasticity group.

Conclusion

Individuals with high spasticity after stroke demonstrated greater impairment of balance control in the frontal plane, which was exacerbated when vision was removed.

Are static and functional balance abilities related in individuals with Multiple Sclerosis?

BACKGROUND

In people with Multiple Sclerosis (pwMS), balance assessment is essential in estimating the risk of falls, monitoring disease progression and verifying the effectiveness of rehabilitative treatment. Clinical tools and instrumental techniques are available for testing static and dynamic balance, but the relationship between such abilities is still not clear. Having information about this link would be important in properly planning the type and number of tests to administer.

METHODS

One hundred and six pwMS (Expanded Disability Status Scale, EDSS 0-6.5) stratified in three sub-groups (Class 1 EDSS 0-1.5, Class 2 EDSS 2-4 and Class 3 EDSS 4.5-6.5) and 42 healthy controls (HC) participated in the study. All underwent static posturography and instrumented Timed-Up-and-Go (TUG) performed using a wearable inertial sensor. Raw data were processed to extract postural sway features, overall duration of TUG and its main sub-phases (i.e. sit-to-stand, 180° turns and stand-to-sit).

RESULTS

All sway parameters of pwMS of Classes 2 and 3, as well as total TUG duration and time necessary to perform 180° turns, were found significantly higher than HC and Class 1 participants. However, poor correlations were found between sway and TUG parameters. When pwMS are grouped, small/moderate correlations (in the range 0.20-0.41) were found between all sway parameters and total TUG duration.

CONCLUSIONS

Static and dynamic balance in pwMS appear scarcely correlated, although both worsen as disability increases. This implies that they should be separately assessed using specific tests to have a complete view of postural control performance in MS.

Use of Nintendo Wii Balance Board for posturographic analysis of Multiple Sclerosis patients with minimal balance impairment

Background

The Wii Balance Board (WBB) has been proposed as an inexpensive alternative to laboratory-grade Force Plates (FP) for the instrumented assessment of balance. Previous studies have reported a good validity and reliability of the WBB for estimating the path length of the Center of Pressure. Here we extend this analysis to 18 balance related features extracted from healthy subjects (HS) and individuals affected by Multiple Sclerosis (MS) with minimal balance impairment.

Methods

Eighteen MS patients with minimal balance impairment (Berg Balance Scale 53.3 ± 3.1) and 18 age-matched HS were recruited in this study. All subjects underwent instrumented balance tests on the FP and WBB consisting of quiet standing with the eyes open and closed. Linear correlation analysis and Bland-Altman plots were used to assess relations between path lengths estimated using the WBB and the FP. 18 features were extracted from the instrumented balance tests. Statistical analysis was used to assess significant differences between the features estimated using the WBB and the FP and between HS and MS. The Spearman correlation coefficient was used to evaluate the validity and the Intraclass Correlation Coefficient was used to assess the reliability of WBB measures with respect to the FP. Classifiers based on Support Vector Machines trained on the FP and WBB features were used to assess the ability of both devices to discriminate between HS and MS.

Results

We found a significant linear relation between the path lengths calculated from the WBB and the FP indicating an overestimation of these parameters in the WBB. We observed significant differences in the path lengths between FP and WBB in most conditions. However, significant differences were not found for the majority of the other features. We observed the same significant differences between the HS and MS populations across the two measurement systems. Validity and reliability were moderate-to-high for all the analyzed features. Both the FP and WBB trained classifier showed similar classification performance (>80%) when discriminating between HS and MS.

Conclusions

Our results support the observation that the WBB, although not suitable for obtaining absolute measures, could be successfully used in comparative analysis of different populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12984-017-0230-5) contains supplementary material, which is available to authorized users.

Validity of the Instrumented Push and Release Test to Quantify Postural Responses in Persons With Multiple Sclerosis

OBJECTIVE

To test the validity of wearable inertial sensors to provide objective measures of postural stepping responses to the push and release clinical test in people with multiple sclerosis.

DESIGN

Cross-sectional study.

SETTING

University medical center balance disorder laboratory.

PARTICIPANTS

Total sample N=73; persons with multiple sclerosis (PwMS) n=52; healthy controls n=21.

MAIN OUTCOME MEASURES

Stepping latency, time and number of steps required to reach stability, and initial step length were calculated using 3 inertial measurement units placed on participants' lumbar spine and feet.

RESULTS

Correlations between inertial sensor measures and measures obtained from the laboratory-based systems were moderate to strong and statistically significant for all variables: time to release (r=.992), latency (r=.655), time to stability (r=.847), time of first heel strike (r=.665), number of steps (r=.825), and first step length (r=.592). Compared with healthy controls, PwMS demonstrated a longer time to stability and required a larger number of steps to reach stability.

CONCLUSIONS

The instrumented push and release test is a valid measure of postural responses in PwMS and could be used as a clinical outcome measures for patient care decisions or for clinical trials aimed at improving postural control in PwMS.

Increased postural sway in persons with multiple sclerosis during short-term exposure to warm ambient temperatures

BACKGROUND

Multiple sclerosis (MS) is a neurological disease marked by demyelination and axonal loss. Individuals with MS experience increases in clinical signs and symptoms during heat exposure.

OBJECTIVE

To test the hypothesis that moderate heat exposure adversely affects postural sway in individuals with MS.

METHODS

Ten individuals with relapsing-remitting MS (50±8y) and nine controls (47±10y) were examined under a Thermal and a Time Control trial. Following a 30min thermoneutral baseline (25°C, 30% relative humidity (RH)), stand tests randomized with eyes open and closed, were performed. For Thermal, subjects were first exposed to 60min of heating (40°C, 30%RH) followed by 60min of cooling (20°C, 30%RH). For Time Control, subjects remained in a thermoneutral environment throughout. Stand tests were repeated at consistent times in both trials.

RESULTS

No difference in skin and core temperatures between groups were observed for any trial (P>0.05). During heating, postural sway was higher in MS relative to control subjects (eyes open, P=0.03; eyes closed, P=0.011). No differences in postural sway, regardless of eye status, were observed during the Time Control trial for either group (P>0.05).

CONCLUSION

These data demonstrate that exposure to a moderate heating environment increases postural sway in patients with MS.

Step initiation interferes with working memory in nondisabled patients with the earliest multiple sclerosis-A dual-task study

Balance and cognition are affected by multiple sclerosis (MS). Cognitive-motor interference (CMI) is important for balance impairment in MS, however little is known about CMI at the earliest stages of the disease. Step initiation (SI) with anticipatory postural adjustments (APAs) has been linked to postural instability and falls in subjects with MS, therefore we aimed to assess CMI between SI and the two storage systems of working memory in patients with clinically isolated syndrome (presented as optic neuritis-ON) suggestive of MS. Twenty patients with normal/near normal visual acuity and 20 age-, weight-, height-, sex- and education-matched control subjects were included. APAs were studied using center of pressure measures in three conditions: SI alone, SI+Brooks' spatial- and SI+2-back verbal working memory task. Decrements (% change) in performance on cognitive tasks and in APA parameters were calculated. CMI was assessed combining the two decrements scores. Performance on both cognitive tasks was more affected by dual-tasking in patients compared to healthy subjects. In both groups APA parameters were not influenced by dual-tasking. CMI was higher in patients compared to healthy subjects. Our results suggest that the disease affects CMI in its earliest stages. Since both cognitive tasks were similarly affected by dual-tasking in patients and controls central executive seems to play the major role in CMI between SI and working memory. Patients prioritizing motor over cognitive task for balance maintenance suggests reduced divided attention capacity as a cause of increased CMI in the earliest MS.

DNA damage and postural balance in multiple sclerosis patients

Abstract Introduction: Multiple Sclerosis (MS) is a chronic inflammatory disease characterized by infiltration of inflammatory cells on the Central Nervous System (CNS). There is evidence that cumulative DNA damage can contribute to various mechanisms underlying MS lesions. Changes in postural balance are frequent observations in subjects with MS. Objective: Evaluated the DNA damage index (DDI)) and postural balance in patients with MS. Methods: A case-control study was conducted with 28 subjects matched for sex, age, and body mass index, divided into MS group and control. The DDI was assessed by comet assay and postural balance through recording the body oscillations of the center of pressure (COP), in the anterior-posterior and lateral middle directions. Results: Showed higher DDI in MS patients (21.3 ± 4.8) than controls (7.9 ± 6.1). Significant differences between groups were also noted in postural control parameters. The wider ranges of postural sway were observed in the MS group. The associations between DDI and postural control parameters showed weak, but significant correlations. No associations were found between DDI and time of diagnosis of MS. Conclusion: People with MS had higher DDI and larger body oscillations than healthy individuals.

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

A major health concern faced by individuals with Multiple Sclerosis (MS) is the heightened risk of falling. Reasons for this increased risk can often be traced back to declines in neurophysiological mechanisms underlying balance control and/or muscular strength. The aim of this study was to assess differences between persons with MS and age-matched healthy adults in regards to their falls risk, strength, reactions and directional control of balance. Twenty-two persons with multiple sclerosis (mean age 56.3±8.9 years) and 22 age-matched healthy adults (mean age 59.1±7.1 years) participated in the study. Assessments of falls risk, balance, fear of falling, lower limb strength, and reaction time were performed. Balance control was assessed under four conditions where the combined effects of vision (eyes open/closed) and standing surface (firm/pliable surface) were evaluated. Results demonstrated that, in comparison to healthy older adults, persons with MS had a significantly higher falls risk, slower reaction times, and weaker lower- limb strength. For balance, persons with MS exhibited greater overall COP motion in both the medio-lateral (ML) and anterior-posterior (AP) directions compared to older adults. Additionally, during more challenging balance conditions, persons from the MS group exhibited greater ML motion compared to sway in the AP direction. Overall, the results confirm that persons with MS are often at a heightened risk of falling, due to the multitude of neuromuscular changes brought about by this disease process. However, the increased ML sway for the MS group could reflect a decreased ability to control side-to-side motion in comparison to controlling AP sway.

A comparison of linear and nonlinear stability parameters in different clinical forms of multiple sclerosis

Background

Multiple sclerosis (MS) is one of the neurological diseases that affect the ability of subjects to stand and walk. The stability of MS subjects has been evaluated in various studies, mostly based on linear approach. Based on this approach it is controversial weather stability of MS subjects differ from normal or not. Therefore, the aim of this study was to evaluate stability in three groups of MS subjects (spastic, ataxic and ataxic-spastic) using both linear and non-linear approaches.

Method

Seventeen healthy and 36 subjects with MS participated in this study. The MS group presenting with spastic, ataxic and ataxic-spastic (each group consisted of 12 subjects) participated in the study. The stability of the subjects was evaluated using Kistler force plate. The difference between stability of the subjects was evaluated using the Multi Analysis of Variance and significant value was set at P < 0.05.

Result

There was a significant difference in the mean value of Approximate Entropy (ApEn) in anterior-posterior direction between normal (0.66 ± 0.13) and ataxic (0.85 ± 0.12) and ataxic-spastic (0.90 ± 0.12) subjects (P < 0.05) and no difference between normal and spastic groups (0.76 ± 0.13). The results of both linear and nonlinear approaches confirmed that both ataxic and ataxic-spastic subjects had more instability than normal subjects. Although, the mean values of stability parameters increased in spastic compared to normal, the difference was not statistically significant.

Conclusion

Subjects with ataxic and ataxic-spastic MS disorder had difficulty in controlling their stability during quiet standing. The results of this study also confirmed that spasticity of muscles surrounding the hip and knee joints did not influence standing stability in patients with spastic MS.

Stride-Time Variability and Fall Risk in Persons with Multiple Sclerosis

Gait variability is associated with falls in clinical populations. However, gait variability's link to falls in persons with Multiple Sclerosis (PwMS) is not well established. This investigation examined the relationship between stride-time variability, fall risk, and physiological fall risk factors in PwMS. 17 PwMS (62.8 ± 7.4 years) and 17 age-matched controls (62.8 ± 5.9 years) performed the 6-minute walk test. Stride-time was assessed with accelerometers attached to the participants' shanks. Stride-time variability was measured by interstride coefficient of variation (CV) of stride-time. The participant's fall risk was measured by the short form physiological profile assessment (PPA). A Spearman correlation analysis was used to determine the relationship between variables. Increased fall risk was strongly associated with increased stride-time CV in both PwMS (ρ = 0.71, p < 0.01) and the controls (ρ = 0.67, p < 0.01). Fall risk was not correlated with average stride-time (p > 0.05). In PwMS, stride-time CV was related to postural sway (ρ = 0.74, p < 0.01) while in the control group, it was related to proprioception (ρ = 0.61, p < 0.01) and postural sway (ρ = 0.78, p < 0.01). Current observations suggest that gait variability is maybe more sensitive marker of fall risk than average gait parameters in PwMS. It was also noted that postural sway may be potentially targeted to modify gait variability in PwMS.

Association of Postural Sway with Disability Status and Cerebellar Dysfunction in People with Multiple Sclerosis: A Preliminary Study

BACKGROUND

The aims of this study were 1) to examine postural sway in the eyes open (EO) and eyes closed (EC) conditions in people with multiple sclerosis (MS) with moderate levels of disability compared with controls and 2) to examine relationships between postural sway and total Expanded Disability Status Scale (EDSS) scores, functional system subscores, and clinical measures of strength and spasticity in the MS group.

METHODS

Thirty-four people with moderate MS and ten matched controls completed measures of postural sway with EO and EC, knee extension and ankle dorsiflexion isometric strength, EDSS total score and subscores, and spasticity levels.

RESULTS

Participants with MS swayed significantly more with EO and EC and had reduced knee extension and ankle dorsiflexion strength compared with controls (P < .001). In the MS group, increased sway was associated with higher total EDSS scores and cerebellar function subscores, whereas increased sway ratio (EC/EO) was associated with reduced sensory function subscores. Postural sway was not significantly associated with strength or spasticity.

CONCLUSIONS

Participants with MS swayed more and were significantly weaker than controls. Cerebellar dysfunction was identified as the EDSS domain most strongly associated with increased sway, and sensory loss was associated with a relatively greater dependence on vision for balance control. These findings suggest that exercise interventions targeting sensory integration and cerebellar ataxia may be beneficial for enhancing balance control in people with MS.

Objective and subjective measures reflect different aspects of balance in multiple sclerosis

The objective of this study was to evaluate relationships between subjective and objective measures of balance in multiple sclerosis (MS). In 54 subjects with MS, balance was measured objectively with the Sensory Organization Test (SOT) using dynamic posturography and subjectively with the Activities-specific Balance Confidence (ABC) Scale and the Falls Efficacy Scale-International (FES-I). MS-related disability was assessed with the Expanded Disability Status Scale (EDSS). Relationships between the magnitude (root mean square, range, and area) as well as velocity of center of pressure sway (calculated from the center of pressure signal from the SOT), composite SOT, ABC Scale, FES-I, and EDSS scores were assessed. The magnitude and velocity of center of pressure sway was statistically significantly correlated with the ABC Scale (rho = -0.2 to -0.5), FES-I (rho = 0.3 to 0.5), and EDSS (rho = 0.3 to 0.4). The composite SOT was also statistically significantly correlated with the ABC Scale, FES-I, and EDSS. Objective balance measures, as reflected by posturography, were significantly related to subjective reports of imbalance and clinical measures of disability in MS. The relationships are moderate to weak, indicating that a comprehensive description of balance problems in people with MS likely requires both objective and subjective balance measures.

Neural correlates of ankle movements during different motor tasks: A feasibility study

This ongoing study investigates the neural correlates of ankle dorsi-plantar flexion in active, passive, and proprioceptive tasks. Specifically, we investigated two proprioceptive matching tasks that required a simple combination of active and passive ankle movements: (1) a memory-based ipsilateral matching task and (2) a contralateral concurrent matching task. As expected, during the passive tasks, subjects recruited the same brain areas involved in the correspondent active movements (primary motor cortex (M1), premotor cortex (PM) supplementary motor cortex (SMA) and primary somatosensory cortex (S1)), but the activations were lower. Instead, in both the proprioceptive matching tasks, subjects recruited more motor and sensory-motor areas of the brain and the activations were greater.

Analysis of foot and ankle disorders and prediction of gait in multiple sclerosis rehabilitation

Background

Multiple sclerosis (MS) is a disease of the central nervous system probably based on the autoimmune mechanism against myelin and the action of lymphocyte T. In the last 50 years, more than 150 descriptive studies regarding MS have focused on the etiopathogeny, treatment, diagnosis and prevention of the progressive evolution of MS. Most recently, studies in the field of rehabilitation and diagnosis have tried to present the postural aspects of control/foot and ankle control and gait pattern in MS. The aim of this study is focused on biomechanical foot analyses of MS patients.

Methods

Our clinical research and functional assessment was based on a scale like the EDSS/Kurtzke score: biomechanical foot assessment used the RSscan force plate to assess the foot loading, impulse and foot-ankle angle (subtalar angle), and pressure distribution methods for statistical analyses. The study included MS patients at the Neurologic Rehabilitation Unit, Craiova, we studied 48 patients (46.04 ± 10.99 years) diagnosed with MS.

Results

This study shows that the major lesion is to the pyramidal system and the average value for functionality index (EDSS score) is 3.03 ± 0.13, where 3 means easy paraparesis or hemiparesis. In considering postural strategies, we observed an instability left to right to be more evident in the swing phase and it influences the under the foot impulse for the next step and postural control. From the analysis of the data and pressure centre position, we can see that the high pressure is on metatarsian II to III and more or less at the heel. This means the development of an ankle strategy necessary to restore balance, stability and motor control cannot be assessed other than by clinical evaluation.

Even if many physicians and physical therapists do use the functional scale in their daily assessment, it does not help us achieve a complex assessment of gait and lower limb behaviour during gait, nor does it provide information about the impact of gait on daily activities and on quality of life.

Conclusions

Biomechanical assessment can help the clinician predict the functional evolution of MS patients without visible clinical gait disorders and allows the development of a strategy for rehabilitation to prevent an incorrect ankle/ankle and foot position, resulting in a lack of motor control.

Burden of disease in multiple sclerosis patients with spasticity in Germany: mobility improvement study (Move I)

OBJECTIVES

To describe the current management patterns of multiple sclerosis (MS) patients with spasticity in Germany and the impact of MS spasticity on quality of life (QoL) and associated costs.

METHODS

Non-interventional, multicentre, cross-sectional and retrospective burden-of-disease study including 414 MS patients with spasticity (age from 25 to 80 years) from 42 clinical practices across Germany. All patients were diagnosed with MS-related spasticity based on neurological examination at least 12 months before inclusion in the study. Three different forms were completed on different aspects of the disease: the patient questionnaire, the chart documentation form and the physician questionnaire.

RESULTS

Mild, moderate and severe spasticity were found in 27.3, 44.0 and 28.7 % of patients, respectively. Associated symptoms and QoL scores were worse in patients with higher degrees of spasticity. In particular, higher mean scores for sleep impairment (mild vs. severe, 2.1 vs. 4.3), mean spasm count (3/day vs. 10.1/day), mean WEIMuS fatigue score (15.8 vs. 19.8), increased walking time (9.6 vs. 20.2 s) and lower mean QoL scores (MSQoL-54 physical subscale, 54.9 vs. 39.5; EQ-5D, 0.60 vs. 0.30) were reported in patients with severe spasticity in comparison to patients with mild spasticity. Patient management mainly comprised physiotherapy (mild vs. severe, 65.5 vs. 85.7 %) and medication (84.2 vs. 64.8 %) with baclofen. The average cost for patients with mild spasticity was €2,268/year, increasing to €8,688/patient/year for patients with severe spasticity. The health insurance costs showed the same trend.

CONCLUSIONS

MS patients with spasticity suffer a significant burden because of resulting disabilities and reduced QoL, especially in cases of severe spasticity. Moreover, spasticity causes high costs that increase with increasing severity.

Postural response latencies are related to balance control during standing and walking in patients with multiple sclerosis

OBJECTIVE

To understand and examine the relation between postural response latencies obtained during postural perturbations and representative measures of balance during standing (sway variables) and walking (trunk motion).

DESIGN

Cross-sectional.

SETTING

University medical center.

PARTICIPANTS

Persons with multiple sclerosis (MS) (n=40) were compared with similar aged control subjects (n=20). There were 20 subjects with MS in the normal walking velocity group and 20 subjects with MS who had slow walking velocity based on a timed 25-foot walk (T25FW) of <5 seconds.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Postural response latency, sway variables, trunk motion variables.

RESULTS

We found that subjects with MS with both slow or normal walking velocities had significantly longer postural response latencies than the healthy control group. Postural response latency was not correlated with the T25FW. Postural response latency was significantly correlated with center of pressure sway variables during quiet standing (root mean square: ρ=.334, P=.04; range: ρ=.385, P=.017; mean velocity: ρ=.337, P=.038; total sway area: ρ=.393, P=.015). Postural response latency was also significantly correlated with motion of the trunk during walking (sagittal plane range of motion: ρ=.316, P=.05; SD of transverse plane range of motion: ρ=-.43, P=.006).

CONCLUSIONS

These findings clearly indicate that slow postural responses to external perturbations in patients with MS contribute to disturbances in balance control during both standing and walking.

Movement strategies for maintaining standing balance during arm tracking in people with multiple sclerosis

The purpose of this study was to quantify hip and ankle movement strategies during a standing arm tracking task in people with multiple sclerosis (MS). Full-body kinematics and kinetics were assessed with motion analysis cameras and force plates in nine MS and nine age-matched control subjects. While standing, participants used their dominant hand to track a target moving around a large horizontal or vertical figure eight on a screen in front of them. The target moved at constant speed, or linearly increasing speeds, with a frequency between 0.05 Hz and 0.35 Hz. Hip and ankle moments and angles during tracking were calculated from kinematic and kinetic measurements. Ratios of peak-to-peak (PP) hip/ankle moments (kinetics) and angles (kinematics) were calculated to determine the strategies of the hips and ankles used to maintain balance during arm movements. Center of mass (CoM) root mean square (RMS) acceleration was calculated as a measure of overall balance performance. The MS group produced larger PP hip/ankle moments at all speeds compared with the control group (P < 0.05). The CoM RMS acceleration increased with tracking speed for both groups but was not significantly different between groups. Additionally, the ratios of hip to ankle moments were highly correlated with the Berg Balance Scale during horizontal steady-speed tracking in MS. These results suggest that people with MS increase the use of the hip during standing arm tracking compared with age-matched control subjects. This adapted strategy might allow people with MS to achieve balance performance similar to control subjects, possibly increasing the importance of the hip in maintaining balance during voluntary movements.