Between-Day Reliability of the Gait Characteristics and Their Changes During the 6-Minute Walking Test in People With Multiple Sclerosis

BACKGROUND

Gait characteristics and their changes during the 6-minute walking test (6MWT) in people with multiple sclerosis (pwMS) have been described in the literature, which one may refer to as walking fatigability in the body function level of the International Classification of Functioning, Disability, and Health. However, whether these metrics are reliable is unknown.

OBJECTIVE

To investigate the between-day reliability of the gait characteristics and their changes in pwMS and healthy controls (HCs).

METHODS

Forty-nine pwMS (EDSS 4.82 ± 1.22 and 54.7 ± 9.36 years) and 23 HCs (50.6 ± 6.1 years) performed the 6MWT, as fast as possible but safely while wearing Inertial Measurement Units. Gait characteristics were measured in the pace, rhythm, variability, asymmetry, kinematics, coordination, and postural control domains and were obtained in intervals of 1 minute during the 6MWT. In addition, gait characteristics change in the last minute compared with the first minute were calculated for all gait variables using a fatigability index (ie, distance walking index). The intraclass correlation coefficient (ICC), Bland-Altman Plots, and Standard error of measurement were applied to investigate reliability.

RESULTS

Reliability of gait characteristics, minute-by-minute, and for their changes (ie, using the fatigability index) ranged from poor to excellent (pwMS: ICC 0.46-0.96; HC: ICC 0.09-0.97 and pwMS: ICC 0-0.72; HC: ICC 0-0.77, respectively).

CONCLUSION

Besides coordination, at least 1 variable of each gait domain showed an ICC of moderate or good reliability for gait characteristics changes in both pwMS and HC. These metrics can be incorporated into future clinical trials and research on walking fatigability.Clinical Trial Registration: NCT05412043.

Safety and effectiveness of cladribine tablets for multiple sclerosis: Results from a single-center real-world cohort

BACKGROUND

Cladribine tablets are a highly effective immune reconstitution therapy licensed for treating relapsing multiple sclerosis (RMS) in Europe since 2017. Currently, there is a high demand for real-world data from different clinical settings on the effectiveness and safety profile of cladribine in MS.

METHODS

Within this report, we retrospectively evaluated the outcomes of RMS patients who received cladribine between August 2018 and November 2021 at our Belgian institute. Patients with data for three effectiveness endpoints, more specifically, relapses, MRI observations, and confirmed disability worsening were incorporated into the analysis of 'no evidence of disease activity' (NEDA-3) re-baselined at 3 months. Safety endpoints included lymphopenia, liver transaminases, and adverse events (AEs) during follow-up. Descriptive statistics and time-to-event analysis were performed, including subgroup analysis by pre-treatment.

RESULTS

Of the 84 RMS patients included in this study (age 42 [33-50], 64.3% female, diagnosis duration 6 [2-11] years, baseline EDSS 2.5 [1.5-3.6]), 14 (16.7%) patients experienced relapses, while disability progression and brain MRI activity occurred in 8.5% (6/71) and 6.3% (5/79). This resulted in 72.6% (n = 69, standard error 6%) retaining NEDA-3 status at the mean follow-up time of 22.6 ± 11.5 months. During the first year after cladribine initiation, disease activity prevailed more in patients with ≥2 prior DMTs and those switching from fingolimod, although both trends were not statistically significant. In terms of safety, 67.9% reported at least one AE during follow-up, the most frequent being fatigue (64.9%) and skin-related problems (38.6%).

CONCLUSION

Overall, our research results confirm cladribine's safety and effectiveness among RMS patients in real-world conditions. After the re-baseline, we observed high rates of NEDA-3-retention, and no new safety signals were noted.

Day-to-day reliability, agreement and discriminative validity of measuring walking-related performance fatigability in persons with multiple sclerosis

BACKGROUND

Day-to-day reliability and cut-off values to detect abnormal walking fatigability (WF) remain to be investigated in persons with multiple sclerosis (pwMS).

METHODS

In all, 49 pwMS (mean Expanded Disability Status Scale (EDSS) ± standard deviation (SD): 3.3 ± 1.9) and 28 matched healthy controls (HC) performed the six-minute walking test (6MWT) on two different days to determine day-to-day reliability (intraclass correlation coefficient (ICC)) and limits of agreement (LOA) for five different equations of WF.

OBJECTIVE

To examine day-to-day reliability, agreement and discriminative validity for measuring WF.

RESULTS AND CONCLUSION

WF expressed as the ratio between the first and sixth minute had the best day-to-day reliability (ICC's range of 0.76-0.95 and 0.60-0.86, respectively) in both pwMS and HC, while LOA were 15% and 7%, respectively. Ecological validity and clinical importance should be further investigated.

Force decline after low and high intensity contractions in persons with multiple sclerosis

OBJECTIVE

Force decline during strong contractions is dominated by changes in the periphery whereas during weaker contraction changes in voluntary activation become more important. We compared force decline and contributing factors in persons with multiple sclerosis (PwMS) during low and high intensity contractions.

METHODS

Index finger abduction force, force evoked by electrical stimulation of the ulnar nerve at rest (RTw), and during MVCs were investigated in 19 PwMS and 19 controls. Participants performed contractions in sets of six contractions (7 s-on, 3 s-off) at 25% or 80% MVC. After each set, a 5 s-MVC was performed with superimposed nerve stimulation followed by RTw. Contractions were repeated until MVC dropped below 80% of initial MVC.

RESULTS

Low compared to high intensity contractions caused a greater decline in voluntary activation and a smaller decline in RTw. Compared to controls, PwMS accomplished equal sets of contractions but showed a smaller decline in RTw. Female PwMS showed poorer voluntary activation. The number of low intensity contractions was associated with sense of fatigue in PwMS.

CONCLUSION

Although, no difference in fatigability was observed, the mechanism contributing to force decline differed between PwMS and controls during submaximal contractions.

SIGNIFICANCE

During weak contractions, fatigue and fatigability are associated in PwMS.

Motor fatigability in persons with multiple sclerosis: Relation between different upper limb muscles, and with fatigue and the perceived use of the arm in daily life

BACKGROUND

Motor fatigability is increasingly acknowledged in persons with MS (pwMS). It is unknown whether fatigability is generalized across upper limb muscles and relates to fatigue and perceived difficulties in upper limb use.

METHODS

This observational case-controlled study included twenty PwMS (median EDSS = 3, range 1.5-6.5) and twenty healthy controls who performed 30″ sustained maximal muscle contractions for index finger abduction, hand grip, elbow flexion and shoulder abduction. A static fatigue index (SFI) was calculated to assess motor fatigability for each muscle group. PwMS completed the Fatigue Severity Scale (FSS) and Modified Fatigue Index Scale (MFIS), to quantify severity and perceived impact of fatigue and the Manual Ability Measure (MAM-36) reflecting perceived difficulty in using the upper limbs. Comparisons between groups and muscles was made by t-tests. Associations between outcomes were calculated with correlation coefficients.

RESULTS

Fatigue was highest in pwMS. PwMS showed preserved muscle strength and a greater motor fatigability in elbow flexors compared to healthy controls. SFI of elbow flexors and shoulder abductors were associated, and contributed to FSS and MFIS. SFI of elbow flexors and finger abductors predicted half of the variation in MAM-36.

CONCLUSION

Increased motor fatigability was only present in elbow flexors of PwMS, indicating that expression of motor fatigability is not generalized. Fatigability was associated with perceived fatigue (impact) and daily life upper limb use. Results are preliminary given the small sample size with predominantly persons with mild MS.

The Assessment of Motor Fatigability in Persons With Multiple Sclerosis: A Systematic Review

Background. Persons with multiple sclerosis (PwMS) are often characterized by increased motor fatigability, which is a performance change on an objectively measured criterion after any type of voluntary muscle contractions. This review summarizes the existing literature to determine which protocols and outcome measures are best to detect or study motor fatigability and the underlying mechanisms in MS. Methods. Two electronic databases, PubMed and Web of Science, were searched for relevant articles published until August 2016 with a combination of multiple sclerosis, fatigability, muscle fatigue, and motor fatigue. Results. A total of 48 articles were retained for data extraction. A variety of fatigability protocols were reported; protocols showed differences in type (isometric vs concentric), duration (15 to 180 s), and number of contractions (fixed or until exhaustion). Also, 12 articles reported motor fatigability during functional movements, predominantly assessed by changes in walking speed; 11 studies evaluated the mechanisms underlying motor fatigability, using additional electrical nerve or transcranial magnetic stimulation. Three articles reported psychometrics of the outcomes. Conclusions. The disparity of protocols and outcome measures to study different aspects of motor fatigability in PwMS impedes direct comparison between data. Most protocols use maximal single-joint isometric contractions, with the advantage of high standardization. Because there is no head-to-head comparison of the different protocols and only limited information on psychometric properties of outcomes, there is currently no gold standard to assess motor fatigability. The disability level, disease phenotype, and studied limb may influence the assessment of motor fatigability in PwMS.

Motor fatigability after low-intensity hand grip exercises in persons with multiple sclerosis

INTRODUCTION

During maximal, sustained contractions, persons with multiple sclerosis (PwMS) show higher motor fatigability in comparison with healthy persons. It is not known if motor fatigability is also different between PwMS and healthy persons during low-intensity exercises. Thus, the aim of this study was to determine the difference in hand grip fatigability between healthy persons and PwMS for both hands during low-intensity hand grip exercises.

METHODS

19 PwMS and 19 healthy controls performed 18min of hand grip exercises at a maximum of 25% of the maximal voluntary strength, with an electronic hand dynamometer. Perceived fatigability, maximal hand grip strength and muscle activity (electromyography) of the wrist flexors and extensors were recorded in between these exercises for the dominant and non-dominant hand.

RESULTS AND DISCUSSION

There was a significant decrease in maximal hand grip strength after exercising in both groups and for both hands, mainly situated in the first 6min. In contrast to what was hypothesized, PwMS did not show more decline in strength than healthy controls, neither in the dominant nor the non-dominant hand. There was no group difference in the increase of the perceived fatigability in the dominant hand. However, for the non-dominant hand, the perceived fatigability after exercising increased more in PwMS than in healthy controls. Additionally, there was no relation between fatigue indices, as assessed with short maximal contractions and the strength decline after low-intensity repetitive exercises.

Upper Limb Rehabilitation in People With Multiple Sclerosis

Background. There has been an increasing research interest in upper limb rehabilitation in multiple sclerosis (MS). The current changes in the research field inquire a new literature review. Objective. This systematic review aimed to provide an overview of the upper limb rehabilitation strategies in people with MS (PwMS). Methods. Articles published in PubMed and Web of Knowledge were selected when written in English, published in the past 25 years, peer reviewed, that included at least 5 PwMS, and described the effects of an intervention study including rehabilitation strategies targeting the upper limbs. Included articles were screened based on title/abstract and full text by 2 independent reviewers. Results. Thirty articles met the criteria and were included for data extraction. Only half of the included studies investigated the effects of a training program specially targeted toward the upper limbs, while in the other studies, a general whole body therapy was used. The therapy content and dosage varied greatly between the different included studies. Multidisciplinary and robot-based rehabilitation were the most investigated rehabilitation strategies and showed to improve upper limb capacity. Strength and endurance training improved the upper limb body functions and structures but did not influence the upper limb capacity and performance. Conclusions. The results of this systematic review indicated that different types of upper limb rehabilitation strategies can improve upper limb function in PwMS. Further research is necessary to compare directly the effects of different rehabilitation strategies and to investigate the optimal therapy dosage according to the upper limb disability level.

Prevalence of Walking-Related Motor Fatigue in Persons With Multiple Sclerosis: Decline in Walking Distance Induced by the 6-Minute Walk Test

OBJECTIVE

To investigate the individual occurrence of walking-related motor fatigue in persons with multiple sclerosis (PwMS), according to disability level and disease phenotype.Study design This was a cross-sectional, multinational study.Participants They were 208 PwMS from 11 centers with Expanded Disability Status Scale (EDSS) scores up to 6.5.

METHODS

The percentage change in distance walked (distance walked index, DWI) was calculated between minute 6 and 1 (DWI(6-1)) of the 6-Minute Walk Test (6MWT). Its magnitude was used to classify participants into 4 subgroups: (1) DWI(6-1)[≥5%], (2) DWI(6-1)[5%; -5%], (3) DWI(6-1)[-5%; > -15%], and (4) DWI(6-1)[≤-15%]. The latter group was labeled as having walking-related motor fatigue. PwMS were stratified into 5 subgroups based on the EDSS (0-2.5, 3-4, 4.5-5.5, 6, 6.5) and 3 subgroups based on MS phenotype (relapsing remitting [RR], primary progressive [PP], and secondary progressive [SP]).

RESULTS

The DWI6-1was ≥5% in 16 PwMS (7.7%), between 5% and -5% in 70 PwMS (33.6%), between -5% and -15% in 58 PwMS (24%), and ≤-15% in 64 PwMS (30.8%). The prevalence of walking-related motor fatigue (DWI(6-1)[≤-15%]) was significantly higher among the progressive phenotype (PP = 50% and SP = 39%; RR = 15.6%) and PwMS with higher disability level (EDSS 4.5-5.5 = 48.3%, 6 = 46.3% and 6.5 = 51.5%, compared with EDSS 0-2.5 = 7.8% and 3-4 = 16.7%;P< .05). Stepwise multiple regression analysis indicated that EDSS, but not MS phenotype, explained a significant part of the variance in DWI(6-1)(R(2)= 0.086;P< .001).

CONCLUSION

More than one-third of PwMS showed walking-related motor fatigue during the 6MWT, with its prevalence greatest in more disabled persons (up to 51%) and in those with progressive MS phenotype (up to 50%). Identification of walking-related motor fatigue may lead to better-tailored interventions.

A clinical measurement to quantify spasticity in children with cerebral palsy by integration of multidimensional signals

Most clinical tools for measuring spasticity, such as the Modified Ashworth Scale (MAS) and the Modified Tardieu Scale (MTS), are not sufficiently accurate or reliable. This study investigated the clinimetric properties of an instrumented spasticity assessment. Twenty-eight children with spastic cerebral palsy (CP) and 10 typically developing (TD) children were included. Six of the children with CP were retested to evaluate reliability. To quantify spasticity in the gastrocnemius (GAS) and medial hamstrings (MEH), three synchronized signals were collected and integrated: surface electromyography (sEMG); joint-angle characteristics; and torque. Muscles were manually stretched at low velocity (LV) and high velocity (HV). Spasticity parameters were extracted from the change in sEMG and in torque between LV and HV. Reliability was determined with intraclass-correlation coefficients and the standard error of measurement; validity by assessing group differences and correlating spasticity parameters with the MAS and MTS. Reliability was moderately high for both muscles. Spasticity parameters in both muscles were higher in children with CP than in TD children, showed moderate correlation with the MAS for both muscles and good correlation to the MTS for the MEH. Spasticity assessment based on multidimensional signals therefore provides reliable and clinically relevant measures of spasticity. Moreover, the moderate correlations of the MAS and MTS with the objective parameters further stress the added value of the instrumented measurements to detect and investigate spasticity, especially for the GAS.

Spatio-temporal gait parameters change differently according to speed instructions and walking history in MS patients with different ambulatory dysfunction

BACKGROUND

Different walking capacity test formats are applied, but their impact on the gait pattern in persons with MS (pwMS) has not yet been investigated according to baseline velocity performance.

OBJECTIVE

To assess, in pwMS with different ambulation dysfunction, the impact of speed instructions and previous walking tests (2 and 6min walking test; 2MWT and 6MWT) on spatiotemporal gait parameters.

METHODS

27 participants, divided in three groups based on usual gait speed (Most Limited Community Walkers; MLCW<0.82m/s, CW>1.14m/s, LCW show intermediate values), completed the 2MWT and 6MWT. Before and after each test, they walked on the GAITRite walkway system at both usual and fastest speed. Spatio-temporal gait parameters were measured and analyzed with ANOVA.

RESULTS

All gait parameters in the MLCW were significantly different from other groups. In contrast to the MLCW, the LCW and CW subgroups showed greater velocity in the fastest compared to usual speed condition, associated with a significant increase in cadence and step length. After the 6MWT, small changes in cadence at usual speed and step time at fastest speed were observed in the MLCW subgroup only. No impact of the 2MWT on gait parameters was found in any group.

CONCLUSIONS

The ability to accelerate was dependent on the severity of ambulatory dysfunction. Prolonged walking during the 6MWT has, in contrast to the 2MWT, some impact on gait parameters in the most disabled group only.

The effect of individually defined physiotherapy in children with cerebral palsy (CP)

AIM

This prospective double blind intervention study aims to evaluate the effectiveness of an individually defined physiotherapy program on the function and gait pattern of 16 children with diplegia (age 3-12 year, GMFCS I-II).

METHOD

A 6 weeks general training program was followed by a specific training program based on individual goals determined by the results of 3D gait analyses, GMFM-88 and a clinical evaluation. Goal attainment scores were used for the evaluation of the achievement of individual goals.

RESULTS

After the general training program, 6.7% of the children achieved the treatment goals, 33.3% stayed at the same level and 60% worsened and this in comparison to 40, 33.3 and 26.6% of the children respectively after the individually defined training program. The improvement for walking, running and jumping of the GMFM-88 was significantly more pronounced after the individually defined (p < 0.05), compared to the general training program. Whereas ankle dorsiflexion, spasticity of the hamstrings (p < 0.01), selectivity of hip abductors, knee extensors and ankle dorsiflexors significantly improved over the complete period of study (p < 0.01), hip extension, step length, stride length, ankle power generation and all hip parameters changed specifically after the individually defined training program (p < 0.01).

CONCLUSION

A quantified effect is manifest with the application of an individually defined training program over a six weeks period.

Time Course of Trunk, Arm, Leg, and Functional Recovery After Ischemic Stroke

Background. Patterns of recovery provide useful information concerning the potential of physical recovery over time and therefore the setting of realistic goals for rehabilitation programs. Objective. To compare the time course of trunk recovery with the patterns of recovery of arm, leg, and functional ability. Methods . Consecutive stroke patients were recruited in 2 acute neurology wards. Participants were evaluated at 1 week, 1 month, and 3 and 6 months after stroke. Patients were assessed with the Trunk Impairment Scale, Fugl-Meyer arm and leg test, and Barthel Index. Results. Thirty-two patients were included in the study. There were no dropouts. Repeated measures analysis of the recovery patterns of motor and functional performance revealed the most striking improvement for all measures from 1 week to 1 month ( P value between .0021 and <.0001) and a significant improvement from 1 month to 3 months after stroke ( P value ranges from .0008 to <.0001). No significant improvement was found between 3 and 6 months after stroke for any of the measures. Statistical analysis revealed no significant difference between time course of trunk, arm, leg, and functional recovery ( P = .2565). No significant differences in level of motor and functional recovery were found at the different time points. Conclusions. Separate analyses of motor and functional recovery patterns after stroke confirm the importance of the first month for recovery. Contrary to common belief, the time course of recovery of the trunk is similar to the recovery of arm, leg, and functional ability.