Is there a relationship between fatigue questionnaires and gait mechanics in persons with multiple sclerosis?

Investigation of parameters related to lower extremity muscle strength and proprioception in Patients with Multiple Sclerosis: a cross-sectional study

BACKGROUND

Patients with Multiple Sclerosis (PwMS) may experience a decline in balance, gait, and mobility as well as an increase in fear of falling (FoF) and fatigue due to weaker muscles and proprioceptive loss in their lower limbs. The study aimed to compare lower extremity muscle strength and proprioception, balance, functional mobility, gait, FoF, and fatigue between PwMS and healthy controls and to investigate the relationship between lower extremity muscle strength and proprioception and balance, functional mobility, gait, FoF, and fatigue in PwMS.

METHODS

The study was completed with 35 PwMS and 35 healthy controls with matching age and gender. The 5 Repetition Sit-to Stand Test (5-STS-test), knee and ankle reposition tests (using a digital inclinometer), the Berg Balance Scale (BBS), the Timed Up and Go (TUG) test, the Dynamic Gait Index (DGI), the Falls Efficacy-International (FES-I), and the Fatigue Severity Scale (FSS) were used for evaluations.

RESULTS

The 5-STS test, knee and ankle reposition tests, TUG, FES-I, and FSS Test scores were higher and BBS and DGI scores were lower in PwMS compared to healthy controls (p < 0.05). BBS, DGI, TUG, FES-I, and FSS were associated with 5-STS test and knee and ankle reposition tests except for some nondominant reposition tests in PwMS (r between 0.342 and -0.714; p < 0.05 for all).

CONCLUSION

Lower extremity muscle strength and proprioception were associated with balance, functional mobility, gait, FoF, and fatigue in PwMS. These results suggested that detailed assessment of neuromuscular parameters in lower extremity function is important in determining the appropriate rehabilitation programs.

Long-term outcomes of semi-implantable functional electrical stimulation for central drop foot

BACKGROUND

Central drop foot is a common problem in patients with stroke or multiple sclerosis (MS). For decades, it has been treated with orthotic devices, keeping the ankle in a fixed position. It has been shown recently that semi-implantable functional electrical stimulation (siFES) of the peroneal nerve can lead to a greater gait velocity increase than orthotic devices immediately after being switched on. Little is known, however, about long-term outcomes over 12 months, and the relationship between quality of life (QoL) and gait speed using siFES has never been reported applying a validated tool. We provide here a report of short (3 months) and long-term (12 months) outcomes for gait speed and QoL.

METHODS

Forty-five consecutive patients (91% chronic stroke, 9% MS) with central drop foot received siFES (Actigait®). A 10 m walking test was carried out on day 1 of stimulation (T1), in stimulation ON and OFF conditions, and repeated after 3 (T2) and 12 (T3) months. A 36-item Short Form questionnaire was applied at all three time points.

RESULTS

We found a main effect of stimulation on both maximum (p < 0.001) and comfortable gait velocity (p < 0.001) and a main effect of time (p = 0.015) only on maximum gait velocity. There were no significant interactions. Mean maximum gait velocity across the three assessment time points was 0.13 m/s greater with stimulation ON than OFF, and mean comfortable gait velocity was 0.083 m/s faster with stimulation ON than OFF. The increase in maximum gait velocity over time was 0.096 m/s, with post hoc testing revealing a significant increase from T1 to T2 (p = 0.012), which was maintained but not significantly further increased at T3. QoL scores showed a main effect of time (p < 0.001), with post hoc testing revealing an increase from T1 to T2 (p < 0.001), which was maintained at T3 (p < 0.001). Finally, overall absolute QoL scores correlated with the absolute maximum and comfortable gait speeds at T2 and T3, and the increase in overall QoL scores correlated with the increase in comfortable gait velocity from T1 to T3. Pain was reduced at T2 (p < 0.001) and was independent of gait speed but correlated with overall QoL (p < 0.001).

CONCLUSIONS

Peroneal siFES increased maximal and comfortable gait velocity and QoL, with the greatest increase in both over the first three months, which was maintained at one year, suggesting that 3 months is an adequate follow-up time. Pain after 3 months correlated with QoL and was independent of gait velocity, suggesting pain as an independent outcome measure in siFES for drop foot.

A randomised double-blind placebo-controlled feasibility trial of flavonoid-rich cocoa for fatigue in people with relapsing and remitting multiple sclerosis

The impact of flavonoids on fatigue has not been investigated in relapsing and remitting multiple sclerosis (RRMS).

OBJECTIVE

To determine the feasibility and estimate the potential effect of flavonoid-rich cocoa on fatigue and fatigability in RRMS.

METHODS

A randomised double-blind placebo-controlled feasibility study in people recently diagnosed with RRMS and fatigue, throughout the Thames Valley, UK (ISRCTN69897291). During a 6-week intervention participants consumed a high or low flavonoid cocoa beverage daily. Fatigue and fatigability were measured at three visits (weeks 0, 3 and 6). Feasibility and fidelity were assessed through recruitment and retention, adherence and a process evaluation.

RESULTS

40 people with multiple sclerosis (10 men, 30 women, age 44±10 years) were randomised and allocated to high (n=19) or low (n=21) flavonoid groups and included in analysis. Missing data were <20% and adherence to intervention of allocated individuals was >75%. There was a small effect on fatigue (Neuro-QoL: effect size (ES) 0.04, 95% CI -0.40 to 0.48) and a moderate effect on fatigability (6 min walk test: ES 0.45, 95% CI -0.18 to 1.07). There were seven adverse events (four control, three intervention), only one of which was possibly related and it was resolved.

CONCLUSION

A flavonoid beverage demonstrates the potential to improve fatigue and fatigability in RRMS.

Physical activity in mild multiple sclerosis: contribution of perceived fatigue, energy cost, and speed of walking

Purpose: To clarify the relationship between leisure-time physical activity, perceived fatigue, and energy expenditure while walking in people with multiple sclerosis.Methods: Sixty-six people afflicted with multiple sclerosis (MS) (32 women) with a mild neurological disability, participated in this study. Energy expenditure was separately measured at rest, during comfortable walking and during fast walking via a portable metabolic device using breath-by-breath technology (COSMED K5, COSMED Srl, Rome, Italy). The Godin leisure-time exercise questionnaire assessed leisure-time physical activity. The Modified Fatigue Impact Scale determined the level of perceived fatigue.Results: Seventeen people with MS were classified as physically active; 49 were insufficiently active. Scores recorded on the Godin Leisure-Time Exercise Questionnaire were 47.8 (SD = 18.4), 7.0 (SD = 8.2), respectively. Insufficiently physically active people with MS walked slower at both normal and fast walking conditions. However, no differences between groups were observed in energy expenditure measures in both walking speeds. O₂ cost was 0.20 (SD = 0.13) and 0.21 (SD = 0.06) in the active and insufficiently active group, respectively. The insufficiently active group reported more perceived fatigue compared with the active patients; 33.3 (SD = 18.6) vs. 15.0 (SD = 19.0), p value = 0.002. Perceived fatigue was a significant variable maintaining a 10.4% variance related to leisure-time physical activity.Conclusions: Leisure-time physical activity was inversely associated with perceived fatigue and walking speed in persons with mild MS. Rehabilitation professionals should be aware of these relationships when planning rehabilitation strategies.Implication for rehabilitationThis study found that perceived fatigue is a barrier to physical activity participation even in people with mild multiple sclerosis and minimal disability.Insufficiently active people with multiple sclerosis expend the same amount of energy while walking as active multiple sclerosis individuals, though walking slower.The relationship between perceived fatigue and physical activity participation requires further exploration in the multiple sclerosis population.

Remote Monitoring in the Home Validates Clinical Gait Measures for Multiple Sclerosis

Background: The timed 25-foot walk (T25FW) is widely used as a clinic performance measure, but has yet to be directly validated against gait speed in the home environment. Objectives: To develop an accurate method for remote assessment of walking speed and to test how predictive the clinic T25FW is for real-life walking. Methods: An AX3-Axivity tri-axial accelerometer was positioned on 32 MS patients (Expanded Disability Status Scale [EDSS] 0-6) in the clinic, who subsequently wore it at home for up to 7 days. Gait speed was calculated from these data using both a model developed with healthy volunteers and individually personalized models generated from a machine learning algorithm. Results: The healthy volunteer model predicted gait speed poorly for more disabled people with MS. However, the accuracy of individually personalized models was high regardless of disability (R-value = 0.98, p-value = 1.85 × 10-22). With the latter, we confirmed that the clinic T25FW is strongly predictive of the maximum sustained gait speed in the home environment (R-value = 0.89, p-value = 4.34 × 10-8). Conclusion: Remote gait monitoring with individually personalized models is accurate for patients with MS. Using these models, we have directly validated the clinical meaningfulness (i.e., predictiveness) of the clinic T25FW for the first time.

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.

Orthotic and therapeutic effect of functional electrical stimulation on fatigue induced gait patterns in people with multiple sclerosis

PURPOSE

To assess the orthotic and therapeutic effects of prolonged use of functional electrical stimulation (FES) on fatigue induced gait patterns in people with Multiple Sclerosis (MS).

METHOD

Thirteen people with MS completed 3D gait analysis with FES off and on, before and after a fatiguing 6-minute walk, at baseline and after 8 weeks of use of FES.

RESULTS

Eleven participants completed all testing. An orthotic effect on gait was not evident on first use of FES. However, therapeutic effects on gait after 8 weeks use were generally positive, including increases in walking speed due to improved neuromuscular control and power generated at the hip and ankle of the more affected limb. The action of FES alone was not sufficient to overcome all fatigue related deficits in gait but there was evidence 8 weeks use of FES can ameliorate some fatigue effects on lower limb kinetics, including benefits to ankle mechanics involved in generating power around push-off during stance.

CONCLUSIONS

Eight-weeks of FES can benefit the gait pattern of people with MS under non-fatigued and fatigued conditions. Implications for rehabilitation In some people with MS prolonged use of FES may be necessary before observing positive orthotic effects. Improvements in the neuromuscular control of the more affected lower limb may develop with prolonged use of FES in people with MS. Only some therapeutic benefits of FES are maintained during fatigued walking in people with MS. FES may be considered as a gait retraining device as well as an orthotic intervention for people with MS.

The correlation between symptomatic fatigue to definite measures of gait in people with multiple sclerosis

There is a general consensus relating to the multidimensional aspects of fatigue in people with multiple sclerosis (PwMS), however, the exact impact of this symptom on gait is not fully understood. Our primary aim was to examine the relationship between definite parameters of gait with self-reported symptomatic fatigue in PwMS according to their level of neurological impairment. Spatio-temporal parameters of gait were studied using an electronic walkway. The Multiple Sclerosis Walking Scale (MSWS-12) questionnaire, a patient-rated measure of walking ability was collected. The Modified Fatigue Impact Scale (MFIS) questionnaire was used to determine the level of symptomatic fatigue. One hundred and one PwMS (61 women) were included in the study analysis. Subjects were divided into mild and moderate neurological impaired groups. Fatigue was correlated with 5 (out of 14) spatiotemporal parameters. However, correlation scores were all <0.35, thus considered as weak correlations. In the mild group, the double support period was the only variable positively correlated to fatigue (Spearman's rho=0.28, P=0.05). In the moderate group, step and stride length were solely negatively correlated to fatigue (Spearman's rho=0.32, P=0.03). In contrast to the definite gait parameters, the MSWS-12 self-questionnaire was moderately positively correlated to the level of fatigue. Scores for the total, mild and moderate groups were 0.54, 0.57 and 0.51; P<0.01, respectively. The present results indicate that modifications in spatio-temporal parameters of gait are not closely related to symptomatic fatigue in PwMS. On the contrary, the self-reported MSWS-12 questionnaire is predisposed to level of fatigue in PwMS.

Association between perceived fatigue and gait parameters measured by an instrumented treadmill in people with multiple sclerosis: a cross-sectional study

BACKGROUND

Multiple sclerosis (MS) is a multi-focal progressive disorder of the central nervous system often resulting in diverse clinical manifestations. Symptomatic fatigue is quite common in people with MS (PwMS), with prevalence as high as 85%. Nevertheless, it remains poorly understood and its association with walking capabilities unclear. Therefore, the objective of this investigation was to examine the relationship between symptomatic fatigue and spatio-temporal parameters of gait in PwMS based on an instrumented treadmill.

METHODS

One hundred and twenty-four relapsing-remitting patients diagnosed with MS, 84 women and 40 men aged 42.6 (S.D = 11.9), participated in this investigation. A convenience sample of 25 apparently healthy subjects, 15 women and 10 men aged 40.3 (S.D = 11.1), served as controls. Gait spatiotemporal parameters were obtained using the Zebris FDM-T Treadmill (Zebris1 Medical GmbH, Germany). The Modified Fatigue Impact Scale (MFIS), a self-reported questionnaire, was used to determine the level of symptomatic fatigue in the MS study group. PwMS were divided into two groups: fatigued and non-fatigued.

RESULTS

Forty-four PwMS were classified as suffering from fatigue (mean MFIS = 52.0, S.D = 13.7); 80 were classified as non-fatigued (mean MFIS = 14.5, S.D = 14.5). Individuals in the fatigued group walked slower than those in the non-fatigued group; 1.7 (S.D = 2.4) vs. 2.4 (S.D = 1.0); P < 0.001, respectively. Moreover, fatigued patients took smaller steps, had a shorter stride length, prolonged stance, double support phase and a shorter single support phase compared to the non-fatigued group. In the total group, fatigue was significantly correlated with 10 (out of 14) spatiotemporal parameters of gait, however, correlation scores <0.40 were considered as weak correlations. According to step one of the linear logistic regression analysis, the temporal gait component was found to explain 5.1% of the variance related to symptomatic fatigue, R2 = 0.051, χ2 (1) = 6.511, P = 0.011. Step two of the model added the gait spatial component, thus increasing the explaining variance to 9.3%; R2 = 0.093, χ2 (2) = 12.12, P = 0.002. The asymmetry gait parameter did not contribute to the equation.

CONCLUSIONS

Perceived fatigue is related to walking speed in PwMS, nevertheless its contribution to level of fatigue is limited.

Neurological disability and its association with walking impairment in multiple sclerosis: brief review

SUMMARY 

Neurological disability and walking impairment are two common, co-varying consequences of multiple sclerosis (MS) that can result in substantial patient burden for daily activities and quality of life. Indeed, neurological disability and walking impairment are driven by pathological changes in the central nervous system, and measurement of walking function is a common method of monitoring the progression of disease and neurological disability. The existing data indicate that the presence of walking impairments range from performance through real-world outcomes based on comparison of MS versus healthy controls, and walking impairments become worse with increasing severity of neurological disability (i.e., progression). Accordingly, researchers and clinicians have considered both pharmaceutical and rehabilitation approaches for managing walking impairment in MS. Both approaches yield beneficial effects on walking outcomes, although the majority of research has focused on exercise training rather than pharmaceutical interventions. Overall, this underscores the importance of continued efforts toward identifying approaches for preventing, forestalling and restoring walking function in persons with MS across the spectrum of neurological disability and its progression.

Dorsiflexion assist orthosis reduces the physiological cost and mitigates deterioration in strength and balance associated with walking in people with multiple sclerosis

OBJECTIVE

To evaluate the effect of wearing a dorsiflexion assist orthosis (DAO) on walking distance, physiological cost, fatigue, and strength and balance measures after a modified 6-minute walk test (6MWT) in people with multiple sclerosis (MS).

DESIGN

Randomized crossover trial.

SETTING

Hospital Movement Laboratory.

PARTICIPANTS

People with moderate MS and Expanded Disability Status Scale score of 3.7±0.7 (N=34; 26 women).

INTERVENTIONS

Modified 6MWT with and without a DAO worn on the weaker leg.

MAIN OUTCOME MEASURES

Distance walked, perceived fatigue, and the physiological cost of walking were compared between walking conditions. Pre- and postwalk changes in knee extensor and ankle dorsiflexor isometric strength and standing postural sway with eyes open and closed were compared between walking conditions.

RESULTS

There were no differences in distance walked or perceived fatigue between the 2 walking conditions. However, there was a reduced physiological cost of walking (P<.05), a smaller reduction in knee extensor strength (P<.05), and a smaller increase in standing postural sway with eyes open (P<.01) after walking while wearing the DAO compared with walking without wearing the DAO.

CONCLUSIONS

Despite not increasing walking distance or reducing perceived fatigue, the DAO reduced the physiological cost of walking and maintained knee strength and standing balance, which may have important implications for physical rehabilitation in people with MS. Further trials are required to determine whether the beneficial effects of wearing a DAO found here are maintained for longer periods.

Gait kinematics of people with multiple sclerosis and the acute application of functional electrical stimulation

This study aimed to (i) compare the gait characteristics of people with Multiple Sclerosis (pwMS) to those of healthy controls walking at the same average speed, and (ii) assess the effects of the acute application of Functional Electrical Stimulation (FES) to the dorsiflexors. Twenty-two people with pwMS (mean age 49 years), prescribed FES, and 11 age matched healthy controls participated. Three dimensional gait kinematics were assessed whilst (i) pwMS and healthy controls walked at self-selected speeds (SSWS), (ii) healthy controls also walked at the average walking speed of the pwMS group, and (iii) people with MS walked using FES. Compared to healthy controls walking at their SSWS, pwMS walked slower and showed differences in nearly all gait characteristics (p<0.001). Compared to healthy controls walking at the same average speed, pwMS still exhibited significantly shorter stride length (p=0.007), reduced dorsiflexion at initial contact (p=0.002), reduced plantar flexion at terminal stance (p=0.008) and reduced knee flexion in swing (p=0.002). However, no significant differences were seen between groups in double support duration (p=0.617), or hip range of motion (p=0.291). Acute application of FES resulted in a shift towards more normal gait characteristics, except for plantar flexion at terminal stance which decreased. In conclusion, compared to healthy controls, pwMS exhibit impairment of several characteristics that appear to be independent of the slower walking speed of pwMS. The acute application of FES improved most impaired gait kinematics. A speed matched control group is warranted in future studies of gait kinematics of pwMS.

Gait characteristics of multiple sclerosis patients in the absence of clinical disability

PURPOSE

Motor deficits in lower extremities and gait abnormalities are a major feature of the multiple sclerosis (MS) patients. Patients with minimal clinical disability have subtle gait changes. The aim of this study was to analyze the gait characteristics of MS patients in the absence of clinical disability.

METHOD

A case-control study was carried out with 12 MS patients and 12 matched healthy controls. The subjects underwent a clinical neurological evaluation to determine their disability level (EDSS ≤ 1.5). Then, the subjects were referred for completion self-report questionnaires (gait, perceived balance confidence, physical activity and fatigue), gait clinical trials, and 3D kinematic analysis.

RESULTS

MS patients showed more impairment of perceived fatigue, perceived of walking impact and perceived balance confidence, despite having no disability. Gait characteristics showed no differences when they were determined by clinical observation. The 3D kinematic analysis of gait showed slight but significant changes in ankle movement.

CONCLUSION

MS patients with no clinical disability have discrete changes in gait that can be evidenced by perceived impact on walking and kinematic evaluation, mainly of ankle movement. Moreover, there is a decrease in perceived balance confidence and an increase in perceived fatigue, which are correlated despite having different origins.

Quantifying gait impairment using an instrumented treadmill in people with multiple sclerosis

Background and Objective. Treadmill gait analysis has been proposed as an attractive alternative for overground walking measuring systems. The purpose of this study was twofold: first to determine spatiotemporal parameters of treadmill gait in patients with multiple sclerosis (MS) and second to examine whether these parameters are associated with specific functional impairments in this cohort. Method. Eighty-seven relapsing-remitting patients diagnosed with MS, 50 women and 37 men, aged 40.9 ± 11.9 with an expanded disability status scale (EDSS) score of 2.7 ± 1.6, participated in this study. Twenty-five apparently healthy subjects, 14 women and 11 men, aged 38.5 ± 9.4, served as controls. Spatiotemporal gait parameters were obtained using the Zebris FDM-T Treadmill (Zebris Medical GmbH, Germany). People with MS demonstrated significantly shorter steps, extended stride time, wider base of support, longer step time, reduced single support phase, and a prolonged double support phase compared to the healthy controls. The EDSS score was significantly correlated with all spatiotemporal gait parameters. Conclusion. The instrumented treadmill may be an effective tool in assessing ambulation capabilities of people with MS.

Prominent fatigue in spinal muscular atrophy and spinal and bulbar muscular atrophy: evidence of activity-dependent conduction block

OBJECTIVES

To clarify whether patients with spinal muscular atrophy (SMA) or spinal and bulbar muscular atrophy (SBMA) suffer disabling muscle fatigue, and whether activity-dependent conduction block (ADCB) contributes to their fatigue. ADCB is usually caused by reduced safety factor for impulse transmission in demyelinating diseases, whereas markedly increased axonal branching associated with collateral sprouting may reduce the safety factor in chronic lower motor neuron disorders.

METHODS

We assessed the fatigue severity scale (FSS) in 22 patients with SMA/SBMA, and in 100 disease controls (multiple sclerosis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy (CIDP), and axonal neuropathy). We then performed stimulated-single fibre electromyography (s-SFEMG) in the extensor digitorum communis (EDC) muscle of 21 SMA/SBMA patients, 6 CIDP patients, and 10 normal subjects.

RESULTS

The FSS score was the highest in SMA/SBMA patients [4.9 ± 1.1 (mean ± SD)], with 81% of them complaining of disabling fatigue, compared with normal controls (3.5 ± 1.0), whereas patients with multiple sclerosis (4.3 ± 1.6), myasthenia gravis (4.0 ± 1.6) or CIDP (4.3 ± 1.4) also showed higher FSS score. When 2000 stimuli were delivered at 20 Hz in s-SFEMG, conduction block of single motor axons developed in 46% of patients with SMA/SBMA, and 40% of CIDP patients, but in none of the normal controls.

CONCLUSION

SMA/SBMA patients frequently suffer from disabling fatigue presumably caused by ADCB induced by voluntary activity.

SIGNIFICANCE

ADCB could be the mechanism for muscle fatigue in chronic lower motor neuron diseases.

Factors for lower walking speed in persons with multiple sclerosis

Objective. The purpose of this study was to analyze factors related to lower walking speed in persons with multiple sclerosis (PwMS). Methods. A cross-sectional survey was conducted. The study participants were 120 consecutive PwMS, who were able to walk, even with device assistance. Demographic and clinical data were collected. Walking speed was measured in 10 m walk test. Possible factors were assessed: disability, fatigue, visual functioning, balance confidence, physical activity level, walking impact, cognitive interference, and motor planning. A forward linear multiple regression analysis examined the correlation with lower speed. Results. Lower walking speed was observed in 85% of the patients. Fatigue (41%), recurrent falls (30%), and balance problems were also present, even with mild disability (average EDSS = 2.68). A good level of physical activity was noted in most of the subjects. Dual-task procedure revealed 11.58% of walking speed reduction. Many participants (69.57%) imagined greater walking speed than motor execution (mean ≥ 28.42%). Physical activity level was the only characteristic that demonstrated no significant difference between the groups (lower versus normal walking speed). Many mobility measures were correlated with walking speed; however, disability, balance confidence, and motor planning were the most significant. Conclusions. Disability, balance confidence, and motor planning were correlated with lower walking speed.

Gait variability and multiple sclerosis

Gait variability, that is, fluctuations in movement during walking, is an indicator of walking function and has been associated with various adverse outcomes such as falls. In this paper, current research concerning gait variability in persons with multiple sclerosis (MS) is discussed. It is well established that persons with MS have greater gait variability compared to age and gender matched controls without MS. The reasons for the increase in gait variability are not completely understood. Evidence indicates that disability level, assistive device use, attentional requirement, and fatigue are related to gait variability in persons with MS. Future research should address the time-evolving structure (i.e., temporal characteristics) of gait variability, the clinical importance of gait variability, and underlying mechanisms that drive gait variability in individuals with MS.

The dynamics of finger tremor in multiple sclerosis is affected by whole body position

Multiple sclerosis (MS) is a disease that results in widespread damage to the nervous system. One consequence of this disease is the emergence of enhanced tremor. This study was designed to (1) compare the tremor responses of persons with MS to that of healthy adults and to (2) examine the impact of whole body position (i.e., seated/standing) on tremor. Bilateral postural tremor was recorded using accelerometers attached to each index finger. Results revealed some similarity of tremor between groups in regard to the principal features (e.g., presence of peaks in similar frequency ranges). However, significant differences were observed with tremor for the MS persons being of greater amplitude, more regular (lower ApEn) and more strongly coupled across limbs compared to the elderly. The effects of body position were consistent across all subjects, with tremor increasing significantly from sitting-to-standing. However, the tremor increase for the MS group was greater than the elderly. Overall, the tremor for MS group was negatively affected by both this disease process and the nature of the task being performed. This latter result indicates that tremor does not simply reflect the feed-forward output of the neuromotor system but that it is influenced by the task constraints.

Gait mechanics are different between healthy controls and patients with multiple sclerosis

Multiple sclerosis (MS) causes severe gait problems in relatively young individuals, yet there have been limited studies to quantitatively identify the specific gait parameters that are affected. The purpose of this study was to define any differences in biomechanical gait parameters between patients with MS and healthy controls. A total of 31 MS patients and 31 healthy controls were evaluated: joint torques and joint powers were calculated at the ankle, knee, and hip during the stance phase of gait. The self-selected walking velocity was used as a covariate in the analysis to ensure that group differences were not due to differences in walking velocity between the MS and healthy control groups. Reduced angular range, less joint torque, and reduced joint power were seen in patients with MS. We also found significant correlations between biomechanical gait parameters and EDSS score, which provides a clinical rating of disease severity. Our findings provide a quantitative assessment of the gait mechanics employed in patients with MS. The altered lower extremity mechanics observed in patients with MS reflect both a neurological and strength deficit compared with healthy controls during walking.