Quantitative measures detect sensory and motor impairments in multiple sclerosis

Factors contributing to falls in people with multiple sclerosis: The exploration of the moderation and mediation effects

BACKGROUND

The prevalence of multiple sclerosis (MS) has significantly increased in recent decades. People with MS have a high risk of falling; these falls may lead to serious injuries, affecting their quality of life PURPOSE: The aim of this study is to assess the factors affecting falls in people with MS and map out the most significant ones. This study also aims to determine whether fatigue has a moderation effect and balance has a mediation effect on falls in people with MS METHODS: In total, 103 people with MS with a mean age of 32.09 ± 7.17 were enrolled. All subjects were assessed for multiple variables including balance using the Berg Balance Scale (BBS), speed of gait using the Timed Up and Go (TUG) test, fear of falling using the Falls Efficacy Scale-International (FES-I), level of fatigue using the Modified Fatigue Impact Scale (MFIS), and lower limb muscle strength using a handheld digital dynamometer RESULTS: Simple binary logistic regression analysis showed significant results for BBS (OR: 10.88; 95% CI: 4.24-27.96; p < 0.0001), TUG (OR: 1.18; 95% CI: 1.09-1.28; p < 0.0001), FES-I (OR: 1.06; 95% CI: 1.02-1.10; p = 0.001), and MFIS (OR: 1.04; 95% CI: 1.02-1.07; p < 0.0001) as factors affecting falls. According to multivariate analysis, balance (OR: 3.924; 95% CI: 1.307-11.780, p = 0.015), speed of gait (OR: 1.122; 95% CI: 1.023-1.231; p = 0.015), and fatigue (OR: 1.029; 95% CI: 1.002-1.058; p = 0.038) were the strongest predicting factors of falls. Hayes's PROCESS analysis showed that fatigue had a significant moderation effect on the relationship between gait speed and falls (MFIS; β; 0.10; p < 0.0001; 95% CI: 0.07-0.14) and balance had a mediation effect on the relationship between gait speed and falls (BBS; indirect effect; 0.08; 95% CI: 0.02-0.13) CONCLUSIONS: People with MS with impaired balance, slower gait speeds, higher levels of fatigue, and a fear of falling were at a high risk of falling. The relationship between gait speed and falls can be mediated by impaired balance and moderated by the level of fatigue. Our data suggest that targeting balance and fatigue while developing rehabilitation interventions could decrease the incidence of falls among people with MS.

Establishment of regression-based normative isometric strength values for major lower limb muscle groups in persons with multiple sclerosis

BACKGROUND

Limb weakness is a major impairment that affects mobility in persons with multiple sclerosis (PwMS). Specifically, lower limb (LL) weakness can greatly affect gait and balance, while increasing fall risk and decreasing quality of life. Numerous studies have compared LL strength of PwMS to healthy controls, however none have objectively measured strength in all major LL joints (hip, knee, and ankle) in a large number of PwMS. Additionally, while discrete normative values exist for knee extensors in PwMS, there has yet to be regression-based normative isometric strength values for all major LL muscle groups. Therefore, this study aimed to develop gender-specific regression-based normative prediction equations, with 95% confidence intervals, for maximal isometric peak torque of major LL muscles in PwMS. A secondary aim was to characterize the prevalence of LL weakness in PwMS, defined as ≥ 2 SD below values reported for healthy individuals.

METHODS

A convenience sample of 175 (women: n = 135) PwMS participated in a prospective, cross-sectional study where isometric peak torque of hip flexors, extensors, and abductors, knee flexors and extensors, and ankle plantarflexors and dorsiflexors were measured using the Biodex System 4 Pro-Dynamometer®. Demographics (age, height, and weight) and disease characteristics (disease duration and disability) were collected. Performances were separated for each muscle group into strongest limb and weakest limb. For each gender, regression-based equations were generated for the LL muscle groups by limb with age, height, weight, disability, and disease duration as the covariates. Descriptive statistics were used to examine the frequency of LL weakness by gender and disability level. For comparison purposes, age-stratified (<30, 30-39, 40-49, 50-59, 60-69, >70 years) and disability-stratified (mild, moderate, and severe ambulant) discrete peak torque values were also generated for each gender.

RESULTS

Regression-based normative data are presented for men and women, accounting for age, height, weight, disability, and disease duration. Men were significantly stronger (P < 0.001) than women for all LL, with the men's models accounting for a greater percent of muscle strength variation than women's models for all muscle groups, except for hip extension. Disability was inversely related to strength in all of the models. LL weakness was prevalent in hip flexion (m: 47.5%; w: 63.0%) and extension (m: 92.5%; w: 88.1%), knee extension (m: 30.0%; w: 33.3%) and flexion (m: 25.0%; w: 34.8%), and ankle plantarflexion (m: 15.0%; w: 10.4%) and dorsiflexion (m: 100.0%; w: 96.3%). PwMS with mild disability had a high prevalence of ankle dorsiflexion (94.9-100.0%) and hip extension (81.4-90.0%) weakness.

CONCLUSIONS

This study is the first to provide regression-based normative data of bilateral strength in all major LL muscle groups and clinically useful prevalence data on the occurrence of weakness in these muscles. Of note, PwMS had a high prevalence of ankle dorsiflexion and hip extension weakness even when they were only mildly disabled. These findings can help guide the direction of future interventions and treatments to improve muscle function in PwMS.

Cognition and proprioception in persons with multiple sclerosis and healthy controls: Nascent findings

BACKGROUND

Although proprioception and cognitive dysfunction are commonly associated with balance impairment and fall risk in persons with multiple sclerosis (MS), the relationship between cognitive functioning and a quantitative measure of proprioception has not been examined in MS.

OBJECTIVE

The primary goals of this study were to determine differences in vibratory sensation, a proxy measure of proprioception between persons with MS and healthy controls, examine relationships between cognition and vibration sensation, and determine the contribution of cognitive function and demographics to vibratory sensation between persons with MS and healthy controls.

METHODS

One hundred and twenty-two individuals with MS, aged 20-60, with Expanded Disability Status Scale (EDSS) scores ≤5.5 and 48 healthy controls completed reaction time testing, the Stroop test and lower extremity vibratory sensation.

RESULTS

Persons with MS performed significantly worse than controls on measures of vibratory sensation (p = 0.001), two-choice reaction time (p = 0.018), and Stroop Incongruent (p < 0.001) Relative Incongruent Score (RIS) (p = 0.047). In MS, average vibration was significantly related to age (p = 0.002), sex (p = 0.038), disease severity (EDSS; p < 0.001), years since diagnosis (p = 0.016), and Stroop Word (p = 0.041). A model with demographics; including age and disease severity, two-choice reaction time, and RIS explained 33.2% of the variance vibratory sensation in persons with MS.

CONCLUSIONS

These results provide early evidence for the relation between cognitive functioning and proprioception in persons with MS and add to prior work linking cognitive functioning, postural control and falls in persons with MS. This work provides a basis for future studies combining quantitative measures of proprioception and cognitive and postural control assessment to improve fall prediction.

Spatiotemporal gait changes in people with multiple sclerosis with different disease progression subtypes

BACKGROUND

Gait impairment is common in people with multiple sclerosis (MS), but less is known about gait differences between MS disease progression subtypes. The objective here was to examine differences in spatiotemporal gait in MS and between relapsing-remitting and progressive subtypes during the timed-25-ft-walk test. Our specific aims were to investigate (1) spatiotemporal, (2) spatiotemporal variability, and (3) gait modulation differences between healthy controls and MS subtypes at preferred and fast walking speed.

METHODS

This study included 27 controls, 18 relapsing-remitting MS, and 13 progressive MS participants. Participants wore six inertial sensors and walked overground without walking aids at preferred and fast-as-possible speeds.

FINDINGS

Both MS groups had significantly lower walking speed than controls, with a trend towards lower preferred gait speed in progressive compared to relapsing-remitting MS (ES = 0.502). Although most spatiotemporal gait parameters differed between controls and MS groups, differences were not significant between MS subtypes in these parameters and their variability, with low to moderate effect sizes during preferred and fast walking. Both MS groups showed reduced modulation in gait compared to controls and no significant differences between MS subtypes.

INTERPRETATION

Gait in MS is altered compared to controls. Although gait may change with progressive MS, the overall small differences in the gait parameters between the MS subtypes observed in this sample suggests that those with the progressive form of MS who are independently ambulatory and without further clinically meaningful changes in gait speed may not show gait decrements greater than the relapsing-remitting form of the disease.

Cerebellar Contributions to Motor and Cognitive Control in Multiple Sclerosis✰✰✰

OBJECTIVE

To evaluate relationships between specific cerebellar regions and common clinical measures of motor and cognitive function in persons with multiple sclerosis (PwMS).

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Twenty-nine PwMS and 28 age- and sex-matched controls without multiple sclerosis (MS) (N=57).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Both diffusion and lobule magnetic resonance imaging analyses and common clinical measures of motor and cognitive function were used to examine structure-function relationships in the cerebellum.

RESULTS

PwMS demonstrate significantly worse motor and cognitive function than controls, including weaker strength, slower walking, and poorer performance on the Symbol Digit Modalities Test, but demonstrate no differences in cerebellar volume. However, PwMS demonstrate significantly worse diffusivity (mean diffusivity: P=.0003; axial diffusivity: P=.0015; radial diffusivity: P=.0005; fractional anisotropy: P=.016) of the superior cerebellar peduncle, the primary output of the cerebellum. Increased volume of the motor lobules (I-V, VIII) was significantly related to better motor (P<.022) and cognitive (P=.046) performance, and increased volume of the cognitive lobules (VI-VII) was also related to better motor (P<.032) and cognitive (P=.008) performance, supporting the role of the cerebellum in both motor and cognitive functioning.

CONCLUSIONS

These data highlight the contributions of the cerebellum to both motor and cognitive function in PwMS. Using novel neuroimaging techniques to examine structure-function relationships in PwMS improves our understanding of individualized differences in this heterogeneous group and may provide an avenue for targeted, individualized rehabilitation aimed at improving cerebellar dysfunction in MS.

Functional connectivity in the dorsal network of the cervical spinal cord is correlated with diffusion tensor imaging indices in relapsing-remitting multiple sclerosis

Focal lesions may affect functional connectivity (FC) of the ventral and dorsal networks in the cervical spinal cord of people with relapsing-remitting multiple sclerosis (RRMS). Resting-state FC can be measured using functional MRI (fMRI) at 3T. This study sought to determine whether alterations in FC may be related to the degree of damage in the normal-appearing tissue. Tissue integrity and FC in the cervical spinal cord were assessed with diffusion tensor imaging (DTI) and resting-state fMRI, respectively, in a group of 26 RRMS participants with high cervical lesion load, low disability, and minimally impaired sensorimotor function, and healthy controls. Lower fractional anisotropy (FA) and higher radial diffusivity (RD) were observed in the normal-appearing white matter in the RRMS group relative to controls. Average FC in ventral and dorsal networks was similar between groups. Significant associations were found between higher FC in the dorsal sensory network and several DTI markers of pathology in the normal-appearing tissue. In the normal-appearing grey matter, dorsal FC was positively correlated with axial diffusivity (AD) (r = 0.46, p = 0.020) and mean diffusivity (MD) (r = 0.43, p = 0.032). In the normal-appearing white matter, dorsal FC was negatively correlated with FA (r = -0.43, p = 0.028) and positively correlated with RD (r = 0.49, p = 0.012), AD (r = 0.42, p = 0.037) and MD (r = 0.53, p = 0.006). These results suggest that increased connectivity, while remaining within the normal range, may represent a compensatory mechanism in response to structural damage in support of preserved sensory function in RRMS.

Evaluating the contribution of reactive balance to prediction of fall rates cross-sectionally and longitudinally in persons with multiple sclerosis

BACKGROUND

Falls are common in persons with multiple sclerosis (PwMS). Reactive postural control-one's response to a balance perturbation-is likely an aspect of fall risk; however, the relationship between reactive posture and falls is poorly understood in PwMS.

OBJECTIVE

We evaluated tibialis anterior muscle onset latency (TA latency) after balance perturbations as a predictor of fall rates in PwMS, controlling for clinical, functional, sensory, psychological, and cognitive factors.

METHOD

At baseline of the 18-month cohort study, 122 participants with MS (EDSS = 2.23) were included. Assessments were conducted every 6 months.

RESULTS

Of the original 122 participants at the baseline collection, data were available from 41, 39, and 34 people at the 6, 12, and 18 month follow-ups, respectively. Percent fallers at the four time points were 35.3%, 12.2%, 15.4%, and 20.5%. Cross-sectionally (i.e., at baseline), the Timed Up-and-Go, Falls Efficacy Scale - International (FES-I), and TA latency after perturbations were significant predictors of retrospective falls rates using negative binomial regression. Longitudinally, random-effects negative binomial regression found that trait-level FES-I, Stroop Color-Word, and TA latency were significant predictors for falls rates.

CONCLUSION

Delays in automatic postural responses seem to account uniquely for fall rates in PwMS-beyond clinical, balance, or mobility measures. These delays may contribute to the increased fall rate in PwMS. In addition to brief self-report instruments (FES-I) and cognitive assessments, muscle onset after balance perturbations may be a valuable tool for predicting falls in those with MS.

A Comparison of Magnetic Resonance Imaging Methods to Assess Multiple Sclerosis Lesions: Implications for Patient Characterization and Clinical Trial Design

Magnetic resonance imaging (MRI) is a sensitive imaging modality for identifying inflammatory and/or demyelinating lesions, which is critical for a clinical diagnosis of MS and evaluating drug responses. There are many unique means of probing brain tissue status, including conventional T1 and T2 weighted imaging (T1WI, T2WI), T2 fluid attenuated inversion recovery (FLAIR), magnetization transfer, myelin water fraction, diffusion tensor imaging (DTI), phase-sensitive inversion recovery and susceptibility weighted imaging (SWI), but no study has combined all of these modalities into a single well-controlled investigation. The goals of this study were to: compare different MRI measures for lesion visualization and quantification; evaluate the repeatability of various imaging methods in healthy controls; compare quantitative susceptibility mapping (QSM) with myelin water fraction; measure short-term longitudinal changes in the white matter of MS patients and map out the tissue properties of the white matter hyperintensities using STAGE (strategically acquired gradient echo imaging). Additionally, the outcomes of this study were anticipated to aid in the choice of an efficient imaging protocol reducing redundancy of information and alleviating patient burden. Of all the sequences used, T2 FLAIR and T2WI showed the most lesions. To differentiate the putative demyelinating lesions from inflammatory lesions, the fusion of SWI and T2 FLAIR was used. Our study suggests that a practical and efficient imaging protocol combining T2 FLAIR, T1WI and STAGE (with SWI and QSM) can be used to rapidly image MS patients to both find lesions and study the demyelinating and inflammatory characteristics of the lesions.

Treatment with electrical stimulation of sensory nerves improves motor function and disability status in persons with multiple sclerosis: A pilot study

Declines in motor function are closely associated with decreases in sensory function in multiple sclerosis (MS). The purpose of our study was to assess the changes in motor function and disability status elicited by transcutaneous electrical nerve stimulation (TENS) to limb muscles of individuals with MS. Fifteen persons with MS and 11 age-matched healthy controls were evaluated before and after receiving 9 treatment sessions during which TENS was applied over the tibialis anterior and rectus femoris muscles of each leg, and over the median nerve and the thenar eminence of each hand. Each evaluation session involved completing two questionnaires (fatigue and walking limitations) and assessing walking performance (2-min test and 25-ft test), dynamic balance (chair-rise test), manual dexterity (grooved pegboard test), and muscle function of hands and legs (strength and force steadiness tests). The MS group exhibited improvements in the 25-ft test (P = 0.001), 2-min test (P = 0.002), chair-rise test (P = 0.008), grooved pegboard test (P = 0.008), and reductions in the self-reported levels of fatigue and walking limitation scores (P = 0.02, d = 0.52; P = 0.008, r = 0.50 respectively). In contrast, there were no statistically significant changes in the Control group. There were no significant changes in either muscle strength or force steadiness for either group. TENS elicited significant improvements in motor function and self-reported disability status in persons with MS. Some improvements reached clinically meaningful levels.

The relationship between plantar sensation and muscle onset during automatic postural responses in people with multiple sclerosis and healthy controls

BACKGROUND

Plantar sensation is critical for balance control in people with multiple sclerosis (PwMS). While previous research has described its impact on standing balance, the influence of plantar sensation during automatic postural responses (APRs) is not well understood in PwMS. The purpose of this study was to characterize the relationship between plantar sensation and APRs in PwMS and controls. A secondary aim was to determine whether the relationship between plantar sensation and APRs is different across PwMS and control groups.

METHODS

122 PwMS and 48 age-matched controls underwent forward and backward support-surface perturbations from stance. The onset of the tibialis anterior (TA) and medial gastrocnemius (MG) were the primary reactive balance outcome measures for backward and forward losses of balance, respectively. Plantar sensation was measured as the vibration sensation threshold (VT).

RESULTS

As expected, PwMS had significantly higher (i.e., worse) VT (p<0.001) and an increased MG and TA onset latency (TA: p<0.001, MG: p = 0.01) compared to the control group. A higher VT was related to increased MG (p<0.001) and TA latency (p<0.001) across all participants. However, no moderating effect of group (control or PwMS) was observed for the relationship between VT and muscle onset (MG: p = 0.14; TA: p = 0.34).

CONCLUSION

PwMS demonstrated poorer plantar sensation and delayed muscle onset during APRs compared to controls. Plantar sensation was also related to muscle onset after perturbations in all participants. Although this relationship was not moderated by group, this may be related to the lack of dynamic range of VT scores in controls. These results indicate that plantar sensation may be related to reactive balance and provides insight into a potential contributing factor of delayed automatic postural responses in people with MS.

Non-ambulatory measures of lower extremity sensorimotor function are associated with walking function in Multiple Sclerosis

BACKGROUND

Disease progression of multiple sclerosis (MS) is often monitored by ambulatory measures, but how non-ambulatory sensorimotor measures differentially associate to walking measures in MS subtypes is unknown. We determined whether there are characteristic differences between relapsing-remitting MS (RRMS), progressive MS (PMS), and non-MS controls in lower extremity sensorimotor function and clinical walking tasks and the sensorimotor associations with walking function in each group.

METHODS

18 RRMS, 13 PMS and 28 non-MS control participants were evaluated in their plantar cutaneous sensitivity (vibration perception threshold, Volts), proprioception during ankle joint position-matching (|∆°| in dorsiflexion), motor coordination (rapid foot-tap count/10 s), and walking function with three tests: Timed 25-foot walk (T25FW) at preferred and fast speeds (s), and timed-up-and-go (TUG, s).

RESULTS

Foot-tapping (p = 0.039, Mean difference (MD)= 5.65 taps) and plantar cutaneous sensation (p = 0.026, MD= -10.30 V) differed between the MS subtypes. For the RRMS group faster walking was related to better proprioceptive function (preferred T25FW: p = 0.019, Root mean square error (RMSE)=1.94; fast T25FW: p = 0.004, RMSE=1.65; TUG: p = 0.001, RMSE=2.12) and foot-tap performance (preferred T25FW: p = 0.033, RMSE = 2.74; fast T25FW: p = 0.010, RMSE=2.02). These associations were not observed in the PMS group.

CONCLUSIONS

Foot-tap performance and plantar cutaneous sensitivity but not ankle proprioception differed between MS subtypes. Lower walking performance was associated with lower foot-tapping and plantar cutaneous sensitivity in the RRMS but not the PMS group. This result suggests a change in the relationship of lower extremity sensorimotor function to walking performance in the PMS subtype.

Five-year longitudinal changes in quantitative spinal cord MRI in multiple sclerosis

BACKGROUND

The spinal cord (SC) is highly relevant to disability in multiple sclerosis (MS), but few studies have evaluated longitudinal changes in quantitative spinal cord magnetic resonance imaging (SC-MRI).

OBJECTIVES

The aim of this study was to characterize the relationships between 5-year changes in SC-MRI with disability in MS.

METHODS

In total, 75 MS patients underwent 3 T SC-MRI and clinical assessment (expanded disability status scale (EDSS) and MS functional composite (MSFC)) at baseline, 2 and 5 years. SC-cross-sectional area (CSA) and diffusion-tensor indices (fractional anisotropy (FA), mean, perpendicular, parallel diffusivity (MD, λ⊥, λ||) and magnetization transfer ratio (MTR)) were extracted at C3-C4. Mixed-effects regression incorporating subject-specific slopes assessed longitudinal change in SC-MRI measures.

RESULTS

SC-CSA and MTR decreased (p = 0.009, p = 0.03) over 5.1 years. There were moderate correlations between 2- and 5-year subject-specific slopes of SC-MRI indices and follow-up EDSS scores (Pearson's r with FA = -0.23 (p < 0.001); MD = 0.31 (p < 0.001); λ⊥ = 0.34 (p < 0.001); λ|| = -0.12 (p = 0.05), MTR = -0.37 (p < 0.001); SC-CSA = -0.47 (p < 0.001) at 5 years); MSFC showed similar trends. The 2- and 5-year subject-specific slopes were robustly correlated (r = 0.93-0.97 for FA, λ⊥, SC-CSA and MTR, all ps < 0.001).

CONCLUSION

In MS, certain quantitative SC-MRI indices change over 5 years, reflecting ongoing tissue changes. Subject-specific trajectories of SC-MRI index change at 2 and 5 years are strongly correlated and highly relevant to follow-up disability. These findings suggest that individual dynamics of change should be accounted for when interpreting longitudinal SC-MRI measures and that measuring short-term change is predictive of long-term clinical disability.

Combining Magnetization Transfer Ratio MRI and Quantitative Measures of Walking Improves the Identification of Fallers in MS

Multiple sclerosis (MS) impacts balance and walking function, resulting in accidental falls. History of falls and clinical assessment are commonly used for fall prediction, yet these measures have limited predictive validity. Falls are multifactorial; consideration of disease-specific pathology may be critical for improving fall prediction in MS. The objective of this study was to examine the predictive value of clinical measures (i.e., walking, strength, sensation) and corticospinal tract (CST) MRI measures, both discretely and combined, to fall status in MS. Twenty-nine individuals with relapsing-remitting MS (mean ± SD age: 48.7 ± 11.5 years; 17 females; Expanded Disability Status Scale (EDSS): 4.0 (range 1-6.5); symptom duration: 11.9 ± 8.7 years; 14 fallers) participated in a 3T brain MRI including diffusion tensor imaging and magnetization transfer ratio (MTR) and clinical tests of walking, strength, sensation and falls history. Clinical measures of walking were significantly associated with CST fractional anisotropy and MTR. A model including CST MTR, walk velocity and vibration sensation explained >31% of the variance in fall status (R2 = 0.3181) and accurately distinguished 73.8% fallers, which was superior to stand-alone models that included only MRI or clinical measures. This study advances the field by combining clinical and MRI measures to improve fall prediction accuracy in MS.

Measurement of white matter fiber-bundle cross-section in multiple sclerosis using diffusion-weighted imaging

BACKGROUND

When investigating white matter (WM) microstructure, the axonal fiber orientation should be considered. Constrained spherical deconvolution (CSD) is a diffusion-weighted imaging (DWI) method that estimates distribution of fibers within each imaging voxel.

OBJECTIVE

To study fiber-bundle cross-section (FC) as measured by CSD in multiple sclerosis (MS) patients versus healthy controls (HCs).

METHODS

DWI and three-dimensional (3D) T₁-weighted magnetic resonance imaging (MRI) were obtained from 45 MS patients and 45 HCs. We applied fixel-based morphometry analysis to assess differences of FC in MS against HCs and voxel-based analysis of fractional anisotropy (FA).

RESULTS

We found a significant widespread reduction of WM FC in MS compared to HCs. The decrease in FA was less extensive, mainly located in regions with high lesion occurrence such as the periventricular WM and the corpus callosum. Progressive MS patients showed a significant FC reduction in the right anterior cingulum, bilateral cerebellum, and in several mesencephalic and diencephalic regions compared to relapsing-remitting MS patients.

CONCLUSION

The CSD method can be applied in MS for a fiber-specific study of WM microstructure and quantification of FC. Fixel-based findings offered greater anatomical specificity and biological interpretability by identifying tract-specific differences and allowed substantial abnormalities to be detected.

Sensorimotor function in progressive multiple sclerosis

BACKGROUND

A sensitive test reflecting subtle sensorimotor changes throughout disease progression independent of mobility impairment is currently lacking in progressive multiple sclerosis.

OBJECTIVES

We examined non-ambulatory measures of upper and lower extremity sensorimotor function that may reveal differences between relapsing-remitting and progressive forms of multiple sclerosis.

METHODS

Cutaneous sensitivity, proprioception, central motor function and mobility were assessed in 32 relapsing-remitting and 31 progressive multiple sclerosis patients and 30 non-multiple sclerosis controls.

RESULTS

Cutaneous sensation differed between relapsing-remitting and progressive multiple sclerosis at the foot and to a lesser extent the hand. Proprioception function in the upper but not the lower extremity differed between relapsing-remitting and progressive multiple sclerosis, but was different for both upper and lower extremities between multiple sclerosis patients and non-multiple sclerosis controls. Foot-tap but not hand-tap speed was slower in progressive compared to relapsing-remitting multiple sclerosis, suggestive of greater central motor function impairment in the lower extremity in progressive multiple sclerosis. In addition, the non-ambulatory sensorimotor measures were more sensitive in detecting differences between relapsing-remitting and progressive multiple sclerosis than mobility assessed with the 25-foot walk test.

CONCLUSION

This study provides novel information about changes in sensorimotor function in progressive compared with relapsing-remitting forms of multiple sclerosis, and in particular the importance of assessing both upper and lower extremity function. Importantly, our findings showed loss of proprioceptive function in multiple sclerosis but also in progressive compared to relapsing-remitting multiple sclerosis.

Force control during submaximal isometric contractions is associated with walking performance in persons with multiple sclerosis

Individuals with multiple sclerosis (MS) experience progressive declines in movement capabilities, especially walking performance. The purpose of our study was to compare the amount of variance in walking performance that could be explained by the functional capabilities of lower leg muscles in persons with MS and a sex- and age-matched control group. Participants performed two walking tests (6-min walk and 25-ft walk), strength tests for the plantar flexor and dorsiflexor muscles, and steady submaximal (10% and 20% maximum) isometric contractions. High-density electromyography (EMG) was recorded during the steady contractions, and the signals were decomposed to identify the discharge times of concurrently active motor units. There were significant differences between the two groups in the force fluctuations during the steady contractions (force steadiness), the strength of the plantar flexor and dorsiflexor muscles, and the discharge characteristics during the steady contractions. Performance on the two walking tests by the MS group was moderately associated with force steadiness of the plantar flexor and dorsiflexor muscles; worse force steadiness was associated with poorer walking performance. In contrast, the performance of the control group was associated with muscle strength (25-ft test) and force steadiness of the dorsiflexors and variance in common input of motor units to the plantar flexors (6-min test). These findings indicate that a reduction in the ability to maintain a steady force during submaximal isometric contractions is moderately associated with walking performance of persons with MS.NEW & NOTEWORTHY The variance in walking endurance and walking speed was associated with force control of the lower leg muscles during submaximal isometric contractions in individuals with multiple sclerosis (MS). In contrast, the fast walking speed of a sex- and age-matched control group was associated with the strength of lower leg muscles. These findings indicate that moderate declines in the walking performance of persons with MS are more associated with impairments in force control rather than decreases in muscle strength.

Does disability level impact the relationship of muscle strength to walking performance in people with multiple sclerosis? a cross-sectional analysis

BACKGROUND AND PURPOSE

Strength training can improve muscle weakness in people with multiple sclerosis (MS), but does not consistently improve walking. Disability level may impact the relationship of muscle weakness and walking performance in people with MS, but few studies have investigated the impact of disability on the relationship of strength and walking. The purpose of this study was to compare the relationships of strength in lower body and trunk muscles to walking performance between mild and moderate disability groups in people with MS.

METHODS

Data from 36 participants with MS who had mild disability (Expanded Disability Status Scale - EDSS 0 to 3.5) and 36 participants who had moderate disability (EDSS 4.0 to 5.5) were analyzed. Hand-held dynamometry measured strength in eight muscle groups from the ankle, knee, hip, and trunk. Timed 25-Foot Walk (T25FW) and 6-Minute Walk Test (6MWT) measured walking speed and endurance, respectively. Pearson correlations and beta coefficients (ß) were reported for each bivariate relationship of muscle strength to T25FW and 6MWT from both mild and moderate disability groups. Linear regression was then used to compare differences in beta coefficients (Δß) between disability groups for the relationship of each muscle variable to T25FW and 6MWT. A positive Δß indicated a stronger relationship of strength to walking performance in the mild disability group, while a negative Δß favored the moderate disability group.

RESULTS

Overall, there were stronger Pearson correlations between muscle strength variables to T25FW and 6MWT in the mild (r = 0.57 to 0.77) compared to moderate disability group (r = 0.10 to 0.54). The mild disability group had significantly greater beta coefficients for T25FW with ankle dorsiflexion (Δß = 0.67, 95%CI: 0.27-1.07), knee extension (Δß = 0.68, 95%CI: 0.28-1.08), and hip abduction (Δß = 0.77, 95%CI: 0.01-1.52); and for 6MWT with knee extension (Δß = 0.47, 95%CI: 0.06 to 0.88).

DISCUSSION AND CONCLUSION

For people with MS, muscle strength in the lower extremity and trunk may be a more important contributor to T25FW in mild versus moderate disability, but not for 6MWT. While more studies are needed, these results may help to inform rehabilitation intervention when prioritizing strength training to improve walking.

Sensory nerve stimulation causes an immediate improvement in motor function of persons with multiple sclerosis: A pilot study

BACKGROUND

Multiple sclerosis (MS) symptoms reported in the first year of the disease include sensory impairment, fatigue, reduced mobility, and declines in hand function. The progressive reduction in motor function experienced by persons living with MS is invariably preceded by changes in sensory processing, which are strongly associated with the declines in both walking performance and manual dexterity.

AIMS

To assess the influence of concurrent sensory stimulation using augmented transcutaneous electrical nerve stimulation (aTENS) applied to leg and hand muscles on clinical tests of motor function in individuals whose mobility was compromised by MS.

METHODS

Thirteen persons with MS (52 ± 8 years; 6 women) and 12 age- and sex-matched healthy adults (52 ± 9 years) met the inclusion criteria. Participants visited the lab on two occasions with one week between visits. Each visit involved the participant performing four tests of motor function and completing two health-related questionnaires (PDDS and MSWS-12). The tests assessed walking performance (6-min test and 25-ft test), dynamic balance (chair-rise tes, and manual dexterity (grooved pegboard test). aTENS was applied through pads attached to the limbs over the tibialis anterior and rectus femoris muscles of the affected leg, and over the median nerve and the thenar eminence of the dominant hand. The pads were attached during both visits, but the current was only applied during the second visit. The stimulation comprised continuous asymmetrical biphasic pulses (0.2 ms) at a rate of 50 Hz and an intensity that elicited slight muscle contractions.

RESULTS

At baseline and during both treatment sessions, the performance on all four tests of motor function was worse for the MS group than the Control group. The MS group experienced significant improvements in all outcomes during the aTENS session with medium-to-large effect sizes. PDDS ratings improved (from 2.8 ± 1.3 to 2.0 ± 1.5; effect size d = -0.70) and the MSWS-12 scores declined (from 36 ± 11 to 28 ± 12; effect size d = -1.52). The concurrent application of aTENS enabled the MS group to walk further during the 6-min test (from 397 ± 174 m to 415 ± 172 m; effect size d = 0.81), to complete the 25-ft test in less time (6.7 ± 3.0 s to 6.3 ± 2.9 s; effect size d = -0.76), to increase the counts in the chair-rise test (from 11.2 ± 3.8 to 13.6 ± 4.8; effect size d = 1.52), and to perform the grooved pegboard test more quickly (from 110 ± 43 s to 99 ± 37 s; effect size d = -0.98). The only significant effect for the Control group was a significant increase in the 6-min walk distance (from 725 ± 79 to 740 ± 82 m; effect size d = 0.87).

CONCLUSIONS

Stimulation of sensory fibers with aTENS evoked clinically significant improvements in four tests of motor function and the self-reported level of walking limitations in persons who were moderately disabled by MS. Moreover, the improvements in function elicited by the concurrent application of aTENS were immediate.

A two alternative forced choice method for assessing vibrotactile discrimination thresholds in the lower limb

The development of an easy to implement, quantitative measure to examine vibration perception would be useful for future application in clinical settings. Vibration sense in the lower limb of younger and older adults was examined using the method of constant stimuli (MCS) and the two-alternative forced choice paradigm. The focus of this experiment was to determine an appropriate stimulation site on the lower limb (tendon versus bone) to assess vibration threshold and to determine if the left and right legs have varying thresholds. Discrimination thresholds obtained at two stimulation sites in the left and right lower limbs showed differences in vibration threshold across the two ages groups, but not across sides of the body nor between stimulation sites within each limb. Overall, the MCS can be implemented simply, reliably, and with minimal time. It can also easily be implemented with low-cost technology. Therefore, it could be a good candidate method to assess the presence of specific deep sensitivity deficits in clinical practice, particularly in populations likely to show the onset of sensory deficits.

Altered visual and somatosensory feedback affects gait stability in persons with multiple sclerosis

Persons with multiple sclerosis (PwMS) often report problems due to sensory loss and have an inability to appropriately reweight sensory information. Both of these issues can affect individual's ability to maintain stability when walking under challenging conditions. The purpose of the current study was to determine how gait stability is adapted when walking under challenging sensory conditions where vision and somatosensation at the feet is manipulated. 25 healthy adults and 40 PwMS (15 fallers, 25 non-fallers) walked on a treadmill at their preferred normal walking speed under 3 conditions: normal walking, altered vision using goggles that shifted visual field laterally, and altered somatosensation using shoes with compliant foam soles. Inertial measurement united recorded acceleration at the lumbar and right ankle, and acceleration variability measures were calculated including root mean square (RMS), range, sample entropy (SaEn), and Lyapunov exponents (LyE). A gait stability index (GSI) was calculated using each of the four variability measures as the ratio of lumbar acceleration variability divided by foot acceleration variability in the frontal and sagittal planes. The sagittal and frontal GSI_RMS were larger in the somatosensory condition compared to the normal and visual conditions (p < 0.001). The frontal GSI_SaEn was greater in the visual condition compared to the somatosensory condition (p = 0.021). The frontal and sagittal GSI_LyE was greater in the somatosensory condition compared to the normal and visual conditions (p < 0.002). The current study showed that HC, MS non-fallers and MS fallers largely adapted to altered sensory feedback during walking in a similar manner. However, MS faller subjects may be more reliant on visual feedback compared to MS non-fallers and HC subjects.

Longitudinal assessment of hand function in individuals with multiple sclerosis

OBJECTIVE

Little is known about the frequency and severity of hand dysfunction in individuals with multiple sclerosis (MS). Hence, we sought to determine the extent that quantitative tests of hand function detect changes over time, evaluate their relationship to global disability measures, and identify predictors of hand function.

METHODS

One-hundred and forty-seven individuals with MS were included (96 women, 84 relapsing-remitting MS [RRMS]) along with 35 age-and-sex matched controls. Quantitative tests of hand function (grip strength, pinch strength, 9 hole peg test [9HPT], finger tapping) and leg strength were acquired and normalized to age and sex. Expanded Disability Status Scale (EDSS) and timed 25 foot walk were also obtained. Spearman correlations, multivariate regression models and mixed effects linear regression were used for analysis.

RESULTS

Our cohort had an EDSS of 3.6 ± 2.2 (median ± SD) and age 44.6 ± 11.9 years. Follow up time was up to 5 years. At baseline, 14/63 individuals with progressive MS (PMS) required more than twice as much time to complete the 9HPT using their dominant hand, compared to controls. Similarly, 11 individuals with PMS had less than 50% of grip strength and 6 had less than 50% of pinch strength, compared to controls. Additionally, 7 individuals with PMS were found to be at least 50% slower than controls in finger tapping. Over two years, 27/85 individuals with MS had more than 20% worsening in their 9HPT results from baseline (17 RRMS, 10 PMS) and 37/74 (20 RRMS, 17 PMS) had more than 20% worsening in their grip strength compared to baseline.

CONCLUSIONS

Hand function is commonly impaired in individuals with MS. Assessing hand dysfunction with dynamometry and the 9HPT could help improve the precision of detecting changes in hand function over time in MS, and may be more sensitive in detecting changes in PMS. These quantitative tests may be useful as outcome measures in clinical trials using neuroprotective or reparative therapies and rehabilitative interventions.

Strength Training to Improve Gait in People with Multiple Sclerosis: A Critical Review of Exercise Parameters and Intervention Approaches

Background

There are mixed reports on the effectiveness of strength training to improve gait performance in people with multiple sclerosis (MS), yet the reasons for these inconsistent results are not clear. Therefore, a critical review was conducted to explore dosage, frequency, mode, position, and muscle targets of studies that have included strength training in people with MS.

Methods

An electronic search was conducted through July 2017. Randomized controlled trials involving people with MS were included that implemented strength training with or without other interventions and assessed 1) strength in the lower extremities and/or trunk and 2) gait speed and/or endurance. Strength and gait results were extracted, along with exercise frequency, intensity, duration, mode, position, and muscle targets.

Results

Thirteen trials met the inclusion criteria; nine used dosing consistent with recommended guidelines. Overall, six studies reported significant between-group strength improvements, and four reported within-group changes. Four studies reported significant between-group gait improvements for gait speed and/or endurance, and two reported within-group changes. Most exercises were performed on exercise machines while sitting, supine, or prone. The most common intervention target was knee extension.

Conclusions

Studies generally improved strength, yet only two studies reported potentially meaningful between-group changes in gait. Future strength intervention studies designed to improve gait might consider dosing beyond that of the minimum intensity to improve strength and explore muscles targets, positions, and modes that are task-specific to walking.

Quantitative vibratory sensation measurement is related to sensory cortical thickness in MS

Objective

Vibratory sensation is a quantifiable measure of physical dysfunction and is often related to spinal cord pathology; however, its association with relevant brain areas has not been fully explored. Our objective was to establish a cortical structural substrate for vibration sensation.

Methods

Eighty‐four individuals with multiple sclerosis (MS) (n = 54 relapsing, n = 30 progressive) and 28 controls participated in vibratory sensation threshold quantification at the great toe and a 3T MRI evaluating volume of the thalamus and cortical thickness primary and secondary sensory cortices.

Results

After controlling for age, sex, and disability level, vibratory sensation thresholds were significantly related to cortical thickness of the anterior cingulate (P = 0.041), parietal operculum (P = 0.022), and inferior frontal gyrus pars operculum (P = 0.044), pars orbitalis (P = 0.007), and pars triangularis (P = 0.029). Within the progressive disease subtype, there were significant relationships between vibratory sensation and thalamic volume (P = 0.039) as well as reduced inferior frontal gyrus pars operculum (P = 0.014) and pars orbitalis (P = 0.005) cortical thickness.

Conclusions

The data show significant independent relationships between quantitative vibratory sensation and measures of primary and secondary sensory cortices. Quantitative clinical measurement of vibratory sensation reflects pathological changes in spatially distinct brain areas and may supplement information captured by brain atrophy measures. Without overt relapses, monitoring decline in progressive forms of MS has proved challenging; quantitative clinical assessment may provide a tool to examine pathological decline in this cohort. These data suggest that quantitative clinical assessment may be a reliable way to examine pathological decline and have broader relevance to progressive forms of MS.

Temperature sensitivity in multiple sclerosis: An overview of its impact on sensory and cognitive symptoms

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease characterized by demyelination of the central nervous system (CNS). The exact cause of MS is still unknown; yet its incidence and prevalence rates are growing worldwide, making MS a significant public health challenge. The heterogeneous distribution of demyelination within and between MS patients translates in a complex and varied array of autonomic, motor, sensory and cognitive symptoms. Yet a unique aspect of MS is the highly prevalent (60-80%) temperature sensitivity of its sufferers, where neurological symptoms are temporarily exacerbated by environmental- or exercise-induced increases (or decreases) in body temperature. MS temperature sensitivity is primarily driven by temperature-dependent slowing or blocking of neural conduction within the CNS due to changes in internal (core) temperature; yet changes in skin temperature could also contribute to symptom exacerbation (e.g. during sunlight and warm ambient exposure). The impact of temperature sensitivity, and particularly of increases in core temperature, on autonomic (e.g. thermoregulatory/cardiovascular function) and motor symptoms (e.g. fatigue) is well described. However, less attention has been given to how increases (and decreases) in core and skin temperature affect sensory and cognitive symptoms. Furthermore, it remains uncertain whether changes in skin temperature alone could also trigger worsening of symptoms. Here we review the impact of temperature sensitivity on MS sensory and cognitive function and discuss additional factors (e.g. changes in skin temperature) that potentially contribute to temperature-induced worsening of symptoms in the absence of alteration in core temperature.

Contributions of Ankle, Knee, Hip, and Trunk Muscle Function to Gait Performance in People With Multiple Sclerosis: A Cross-Sectional Analysis

BACKGROUND

The relative importance of lower extremity and trunk muscle function to gait in people with multiple sclerosis (MS) is unknown.

OBJECTIVE

This study aimed to investigate the association of lower extremity and trunk muscle function with gait performance in people who have MS and mild-to-moderate disability.

DESIGN

This was a cross-sectional, observational study.

METHODS

Participants were people who had an Expanded Disability Status Scale score of ≤ 5.5. Eleven lower extremity and trunk muscles were assessed using handheld dynamometry or endurance tests. Gait performance was assessed with the Timed 25-Foot (7.62 m) Walk (T25FW) and 6-Minute Walk Test (6MWT). Regression analysis was used to quantify the association between gait outcomes and muscle variables.

RESULTS

Seventy-two participants with MS and a mean Expanded Disability Status Scale score of 3.5 (SD = 1.14) were enrolled. Adjusted for age and sex, the multivariate model including hip abduction, ankle plantar flexion, trunk flexion, and knee flexion explained 57% of the adjusted variance in the T25FW; hip abduction, ankle plantar flexion, and trunk flexion explained 61% of the adjusted variance in the 6MWT. The strongest predictors were ankle plantar flexion endurance for the T25FW and hip abduction strength for the 6MWT: a 1-SD increase in ankle plantar flexion (15.2 heel-raise repetitions) was associated with a 0.33-second reduction in the T25WT (95% CI = - 0.71 to - 0.14 seconds); a 1-SD increase in normalized hip abduction strength (0.14 kg/body mass index) was associated with a 54.4-m increase in the 6MWT (28.99 to 79.81 m).

LIMITATIONS

Different measurement scales for independent variables were included because the muscle function assessment used either force or endurance.

CONCLUSIONS

For the major muscles in the lower extremity and trunk, hip abduction, ankle plantar flexion, trunk flexion, and knee flexion were the strongest predictors of gait performance.

Peripheral neuropathy in patients with multiple sclerosis

OBJECTIVES

To determine the prevalence and severity of neuropathic pain, sudomotor dysfunction and abnormal vibration perception in patients with MS.

METHODS

73 patients with MS and 32 age-matched healthy controls underwent assessment of expanded disability severity score (EDSS), DN4 to assess neuropathic pain, electrochemical skin conductance (ESC) to assess sudomotor function and vibration perception threshold (VPT).

RESULTS

Patients with MS had a higher DN4 score (p < 0.001) with 14% fulfilling the criteria for neuropathic pain elevated VPT (p < 0.001) and lower ESC on the feet (p < 0.001) and hands (p < 0.001) compared to control participants. ESC on the feet (32% of MS patients) and hands (30% of MS patients) were lower, and DN4 (77% of MS patients) and VPT (64% of MS patients) were greater than 2SD of the healthy control values, respectively. EDSS correlated with the number of relapses (r = 0.564, p < 0.001), VPT (r = -0.457, < 0.001) and ESC on the feet (r = -0.268, p = 0.023).

CONCLUSIONS

Patients with multiple sclerosis have evidence of sudomotor dysfunction and elevated vibration perception, which were associated with neurological disability from MS.

Dynamic Balance Is Related to Physiological Impairments in Persons With Multiple Sclerosis

OBJECTIVES

To compare physiological impairments between persons with multiple sclerosis (MS) with a history of falls and persons with MS without a history of falls, and to investigate the association between physiological impairments and dynamic balance.

DESIGN

Cross-sectional study.

SETTING

University motion analysis laboratory.

PARTICIPANTS

Persons with MS (N=55; 27 recurrent fallers and 28 nonfallers). Participants were classified as fallers if they self-reported ≥2 falls in the previous 6 months.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Physiological impairment was assessed with sensorimotor delays, spasticity, plantar cutaneous sensation, and the sensory, cerebellar, and pyramidal subscales of the Expanded Disability Status Scale (EDSS). Dynamic balance was assessed using the average and variability of margin of stability and variability of trunk accelerations.

RESULTS

Compared with nonfallers, fallers had lower plantar sensation, longer sensorimotor delays, more spasticity, and more impairment in the pyramidal and cerebellar subscales of the EDSS. Additionally, these impairments were all moderately to strongly correlated with worse dynamic balance.

CONCLUSIONS

This study highlights the multifactorial nature of instability in persons with MS. A better understanding of the physiological mechanisms of dynamic instability in persons with MS can be used to improve methods of monitoring disease progression, identifying which impairments to target through interventions, and appropriately evaluating intervention efficacy.

Somatosensory impairment and its association with balance limitation in people with multiple sclerosis

BACKGROUND

Somatosensory impairments are common in multiple sclerosis. However, little data are available to characterize the nature and frequency of these problems in people with multiple sclerosis.

OBJECTIVE

To investigate the frequency of somatosensory impairments and identify any association with balance limitations in people with multiple sclerosis.

METHODS

The design was a prospective cross-sectional study, involving 82 people with multiple sclerosis and 30 healthy controls. Tactile and proprioceptive sensory acuity were measured using the Rivermead Assessment of Somatosensory Performance. Vibration duration was assessed using a tuning fork. Duration for the Timed Up and Go Test and reaching distance of the Functional Reach Test were measured to assess balance limitations. The normative range of sensory modalities was defined using cut-off points in the healthy participants. The multivariate linear regression was used to identify the significant predictors of balance in people with multiple sclerosis.

RESULTS

Proprioceptive impairments (66.7%) were more common than tactile (60.8%) and vibration impairments (44.9%). Somatosensory impairments were more frequent in the lower limb (78.2%) than the upper limb (64.1%). All sensory modalities were significantly associated with the Timed Up and Go and Functional Reach tests (p<0.05). The Timed Up and Go test was independently predicted by the severity of the neurological lesion, Body Mass Index, ataxia, and tactile sensation (R2=0.58), whereas the Functional Reach test was predicted by the severity of the neurological lesion, lower limb strength, and vibration sense (R2=0.49).

CONCLUSIONS

Somatosensory impairments are very common in people with multiple sclerosis. These impairments are independent predictors of balance limitation.

Psychometric Properties of a Clinical Strength Assessment Protocol in People with Multiple Sclerosis

BACKGROUND

Strength training in people with multiple sclerosis (MS) is an important component of rehabilitation, but it can be challenging for clinicians to quantify strength accurately and reliably. This study investigated the psychometric properties of a clinical strength assessment protocol using handheld dynamometry and other objective, quantifiable tests for the lower extremities and trunk in people with MS.

METHODS

This study determined discriminant validity between 25 participants with MS and 25 controls and between participants with MS who had higher versus lower disability; test-retest reliability across 7 to 10 days; and response stability. The protocol included handheld dynamometry measurements of ankle dorsiflexion, knee flexion and extension; hip flexion, extension, abduction, and adduction; and trunk lateral flexion. Muscular endurance tests were used to measure trunk extension, trunk flexion, and ankle plantarflexion.

RESULTS

The protocol discriminated between participants with MS and controls for all muscles tested (P < .001-.003). The protocol also discriminated between low- and moderate-disability groups (P = .001-.046) for 80% of the muscles tested. Test-retest reliability intraclass correlation coefficients were high (0.81-0.97). Minimal detectable change as a percentage of the mean was 13% to 36% for 85% of muscles tested.

CONCLUSIONS

This study provides evidence for the discriminant validity, test-retest reliability, and response stability of a strength assessment protocol in people with MS. This protocol may be useful for tracking outcomes in people with MS for clinical investigations and practice.

Assessment of Early Evidence of Multiple Sclerosis in a Prospective Study of Asymptomatic High-Risk Family Members

Importance

Subclinical inflammatory demyelination and neurodegeneration often precede symptom onset in multiple sclerosis (MS).

Objective

To investigate the prevalence of brain magnetic resonance imaging (MRI) and subclinical abnormalities among asymptomatic individuals at risk for MS.

Design, Setting, and Participants

The Genes and Environment in Multiple Sclerosis (GEMS) project is a prospective cohort study of first-degree relatives of people with MS. Each participant's risk for MS was assessed using a weighted score (Genetic and Environmental Risk Score for Multiple Sclerosis Susceptibility [GERSMS]) comprising an individual's genetic burden and environmental exposures. The study dates were August 2012 to July 2015.

Main Outcomes and Measures

Participants in the top and bottom 10% of the risk distribution underwent standard and quantitative neurological examination, including disability status, visual, cognitive, motor, and sensory testing, as well as qualitative and quantitative neuroimaging with 3-T brain MRI and optical coherence tomography.

Results

This study included 100 participants at risk for MS, with 41 at higher risk (40 women [98%]) and 59 at lower risk (25 women [42%]), at a mean (SD) age of 35.1 (8.7) years. Given the unequal sex distribution between the 2 groups, the analyses were restricted to women (n = 65). When considering all measured outcomes, higher-risk women differed from lower-risk women (P = .01 by omnibus test). Detailed testing with a vibration sensitivity testing device in a subgroup of 47 women showed that higher-risk women exhibited significantly poorer vibration perception in the distal lower extremities (P = .008, adjusting for age, height, and testing date). Furthermore, 5 of 65 women (8%) (4 at higher risk and 1 at lower risk) met the primary neuroimaging outcome of having T2-weighted hyperintense brain lesions consistent with the 2010 McDonald MRI criteria for dissemination in space. A subset of participants harbor many different neuroimaging features associated with MS, including perivenous T2-weighted hyperintense lesions and focal leptomeningeal enhancement, consistent with the hypothesis that these individuals are at higher risk of developing clinical symptoms of MS than the general population.

Conclusions and Relevance

Higher-risk asymptomatic family members of patients with MS are more likely to have early subclinical manifestations of MS. These findings underscore the importance of early detection in high-risk individuals.

Trial Registration

clinicaltrials.gov Identifier: NCT01353547.

Quantitative measures of walking and strength provide insight into brain corticospinal tract pathology in multiple sclerosis

At least 85% of individuals with multiple sclerosis report walking dysfunction as their primary complaint. Walking and strength measures are common clinical measures to mark increasing disability or improvement with rehabilitation. Previous studies have shown an association between strength or walking ability and spinal cord MRI measures, and strength measures with brainstem corticospinal tract magnetization transfer ratio. However, the relationship between walking performance and brain corticospinal tract magnetization transfer imaging measures and the contribution of clinical measurements of walking and strength to the underlying integrity of the corticospinal tract has not been explored in multiple sclerosis. The objectives of this study were explore the relationship of quantitative measures of walking and strength to whole-brain corticospinal tract-specific MRI measures and to determine the contribution of quantitative measures of function in addition to basic clinical measures (age, gender, symptom duration and Expanded Disability Status Scale) to structural imaging measures of the corticospinal tract. We hypothesized that quantitative walking and strength measures would be related to brain corticospinal tract-specific measures, and would provide insight into the heterogeneity of brain pathology. Twenty-nine individuals with relapsing-remitting multiple sclerosis (mean(SD) age 48.7 (11.5) years; symptom duration 11.9(8.7); 17 females; median[range] Expanded Disability Status Scale 4.0 [1.0-6.5]) and 29 age and gender-matched healthy controls (age 50.8(11.6) years; 20 females) participated in clinical tests of strength and walking (Timed Up and Go, Timed 25 Foot Walk, Two Minute Walk Test ) as well as 3 T imaging including diffusion tensor imaging and magnetization transfer imaging. Individuals with multiple sclerosis were weaker (p = 0.0024) and walked slower (p = 0.0013) compared to controls. Quantitative measures of walking and strength were significantly related to corticospinal tract fractional anisotropy (r > 0.26; p < 0.04) and magnetization transfer ratio (r > 0.29; p < 0.03) measures. Although the Expanded Disability Status Scale was highly correlated with walking measures, it was not significantly related to either corticospinal tract fractional anisotropy or magnetization transfer ratio (p > 0.05). Walk velocity was a significant contributor to magnetization transfer ratio (p = 0.006) and fractional anisotropy (p = 0.011) in regression modeling that included both quantitative measures of function and basic clinical information. Quantitative measures of strength and walking are associated with brain corticospinal tract pathology. The addition of these quantitative measures to basic clinical information explains more of the variance in corticospinal tract fractional anisotropy and magnetization transfer ratio than the basic clinical information alone. Outcome measurement for multiple sclerosis clinical trials has been notoriously challenging; the use of quantitative measures of strength and walking along with tract-specific imaging methods may improve our ability to monitor disease change over time, with intervention, and provide needed guidelines for developing more effective targeted rehabilitation strategies.

Postural Motor Learning Deficits in People With MS in Spatial but Not Temporal Control of Center of Mass

Background: Multiple sclerosis (MS) is associated with balance deficits resulting in falls and impaired mobility. Although rehabilitation has been recommended to address these balance deficits, the extent to which people with MS can learn and retain improvements in postural responses is unknown. Aim: To determine the ability of people with MS to improve postural control with surface perturbation training. Methods: A total of 24 patients with mild MS and 14 age-matched controls underwent postural control training with a set pattern of continuous, forward-backward, sinusoidal, and surface translations provided by a force platform. Postural control was then tested the following day for retention. The primary outcome measures were the relative phase and center-of-mass (CoM) gain between the body CoM and the platform motion. Results: People with MS demonstrated similar improvements in acquiring and retaining changes in the temporal control of the CoM despite significant deficits in postural motor performance at the baseline. Both MS and control groups learned to anticipate the pattern of forward-backward perturbations, so body CoM shifted from a phase-lag (age-matched controls [CS] = −7.1 ± 1.3; MS = −12.9 ± 1.0) toward a phase-lead (CS = −0.7 ± 1.8; MS = −6.1 ± 1.4) relationship with the surface oscillations. However, MS patients were not able to retain the changes in the spatial control of the CoM acquired during training. Conclusions: People with MS have the capacity to improve use of a feed-forward postural strategy with practice and retain the learned behavior for temporal not spatial control of CoM, despite their significant postural response impairments.

Gait characteristics according to pyramidal, sensory and cerebellar EDSS subcategories in people with multiple sclerosis

Walking deterioration is a common problem in people with multiple sclerosis (PwMS). However, there are only scarce data examining the contribution of specific neurological functional systems on gait performance in multiple sclerosis (MS). Therefore, the objective of the current study was to examine the differences in spatio-temporal parameters of gait according to the pyramidal, cerebellar and sensory functional systems. The cross-sectional study included 289 PwMS with mean disease duration of 8.0 (SD = 8.2) years. Spatio-temporal parameters of gait were studied using an electronic walkway. The sample pool was divided into six groups according to the scores of the pyramidal, cerebellar and sensory functional systems, derived from the expanded disability status scale data. Findings indicated that asymmetry of the step time and asymmetry of the single support were significantly elevated in the pyramidal group compared to the sensory group; 9.4 (SD = 10.6) vs. 3.1 (SD = 6.7), P value = 0.004; 9.3 (SD = 10.4) vs. 2.7 (2.1), P value = 0.001, respectively. Additionally, patients in the pure sensory group walked significantly faster with longer strides and less asymmetry compared to the pyramidal-cerebellar-sensory group. Moreover, patients in the sensory group walked with longer steps/strides and symmetry compared to the patients in the pyramidal-cerebellar group. This study confirms that pyramidal disorders are main contributors of gait impairments in the MS population. Furthermore, patients with sensory impairments have a relatively preserved gait pattern compared to patients affected by the pyramidal system.

The Relationship Between Brain MR Spectroscopy and Disability in Multiple Sclerosis: 20-Year Data from the U.S. Glatiramer Acetate Extension Study

BACKGROUND AND PURPOSE

Conventional MRI techniques do not necessarily provide information about multiple sclerosis (MS) disease pathology or progression. Nonconventional MRI techniques, including proton magnetic resonance spectroscopy (¹H‐MRS), are increasingly used to improve the qualitative and quantitative specificity of MR images. This study explores potential correlations between MRI measures of disease and disability progression as measured by the Expanded Disability Status Scale (EDSS), Functional Systems (FS), and ambulation index scores in a unique cohort of MS patients treated with glatiramer acetate that has been closely monitored for over 20 years.

METHODS

This was a multicenter, open‐label, cross‐sectional MRI substudy among participants in the GA‐9004 open‐label extension of the 36‐month, double‐blind GA‐9001 study, timed to coincide with the prospectively planned 20‐year clinical exam.

RESULTS

Of 64 patients who participated in the MRI substudy, results are presented for the 39 patients (61%) who had a ¹H‐MRS assessment at 20 years of treatment. Both total N‐acetylaspartate relative to total creatinine (tNAA/tCr) concentration ratio and T1 lesion volume were found to be robustly associated with disability levels with different statistical approaches. Gray matter (GM) volume was found to be a more consistent parameter than white matter (WM) volume for disability allocation. The elastic net algorithm showed a trade‐off between WM and GM volumes for disability estimation when different disability definitions were used.

CONCLUSIONS

Among patients with MS receiving long‐term glatiramer acetate therapy, consistent effects on disability levels indicated by EDSS and pyramidal FS score thresholds were found for tNAA/tCr concentration ratio and T1 lesion volume.

Interrater Reliability of Four Sensory Measures in People with Multiple Sclerosis

BACKGROUND

Sensory disturbances are a major problem for people with multiple sclerosis (MS), and up to 80% of people with MS present with various sensory deficits. To date, only one study has investigated the reliability of sensory measures in people with MS. We sought to determine the interrater reliability of the verbal analogue scale (VAS), the Erasmus MC modifications to the revised Nottingham Sensory Assessment (EmNSA), Semmes-Weinstein monofilaments (SWMs), and the neurothesiometer (NT) in people with MS.

METHODS

A random sample of 34 people with MS who could walk independently with or without a device was tested by two raters on the same day. For categorical data, percentage agreement, Cohen's kappa, and prevalence-adjusted bias-adjusted kappa were used. For continuous data, interclass correlation coefficient (ICC[2,1]) with 95% confidence intervals (95% CIs), Bland and Altman analysis, and standard error of measurement (SEM) were calculated.

RESULTS

For NT, ICC(2,1) values were good, with the highest for first metatarsophalangeal joint (ICC[2,1] = 0.84, 95% CI = 0.69-0.92, SEM = 4.98). The highest ICC(2,1) for VAS was for the question relating to feeling numbness in the hand (ICC[2,1] = 0.93, 95% CI = 0.86-0.96, SEM = 0.64). Findings for EmNSA and SWMs need further verification owing to possible ceiling effects.

CONCLUSIONS

The NT and VAS had good interrater reliability and should be considered for measuring sensation in ambulatory people with MS. Findings for EmNSA and SWMs revealed either questionable or poor reliability, suggesting the need for further investigation.

Adapted Resistance Training Improves Strength in Eight Weeks in Individuals with Multiple Sclerosis

Hip weakness is a common symptom affecting walking ability in people with multiple sclerosis (MS). It is known that resistance strength training (RST) can improve strength in individuals with MS, however; it remains unclear the duration of RST that is needed to make strength gains and how to adapt hip strengthening exercises for individuals of varying strength using only resistance bands. This paper describes the methodology to set up and implement an adapted resistance strength training program, using resistance bands, for individuals with MS. Directions for pre- and post-strength tests to evaluate efficacy of the strength-training program are included. Safety features and detailed instructions outline the weekly program content and progression. Current evidence is presented showing that significant strength gains can be made within 8 weeks of starting a RST program. Evidence is also presented showing that resistance strength training can be successfully adapted for individuals with MS of varying strength with little equipment.

Quantitative sensory and motor measures detect change overtime and correlate with walking speed in individuals with multiple sclerosis

BACKGROUND

Impairments of sensation, strength, and walking are common in multiple sclerosis (MS). The relationship among these abnormalities and how they change over time remains unclear.

OBJECTIVE

To determine the extent that quantitative lower extremity sensory and motor measures detect abnormalities over time, relate to global disability, and to walking speed in individuals with MS.

METHODS

This prospective, longitudinal analysis evaluated 136 MS subjects. Measures included measures of leg strength, sensation, the Expanded Disability Status Scale(EDSS) and timed 25-foot walk test (T25FW). Mixed effects regression models were used.

RESULTS

Our cohort׳s mean age is 44.3±10.8 years (mean±SD), EDSS score range 0–7.5, 66% were females, and follow-up time was 2.1±1.2 years. Strength significantly changed over time; the RRMS group demonstrated the greatest changes in ADF (3.3 lbs/yr) while the PPMS group showed significant HF changes (−2.1 lbs/yr). Walking speed was affected most by HF, especially in the weakest individuals (HF<20 lbs); T25FW increased by 0.20 s for each 1 lb loss (p=0.001). Likewise T25FW changed by 0.19 s for each 1 lb change in ADF (p<0.01).

CONCLUSION

Quantitative measures detected changes in sensation and strength over time, despite a stable respective functional systems scores of the EDSS. Quantitative measurement tools may improve the sensitivity of disability measures in MS and further investigation of these tools as outcomes in future clinical trials of rehabilitative and neuroreparative interventions is warranted.

Selecting Rehabilitation Outcome Measures for People with Multiple Sclerosis

Despite the well-known benefits of using standardized outcome measures (OMs) in clinical practice, a variety of barriers interfere with their use. In particular, rehabilitation therapists lack sufficient knowledge in selecting appropriate OMs. The challenge is compounded when working with people with multiple sclerosis (MS) owing to heterogeneity of the patient population and symptom variability in individual patients. To help overcome these barriers, the American Physical Therapy Association appointed the Multiple Sclerosis Outcome Measures Task Force to review and make evidence-based recommendations for OM use in clinical practice, education, and research specific to people with MS. Sixty-three OMs were reviewed based on their clinical utility, psychometric properties, and a consensus evaluation of the appropriateness of use for people with MS. We sought to illustrate use of the recommendations for two cases. The first case involves a 43-year-old man with new-onset problems after an exacerbation. The second case pertains to an outpatient clinic interested in assessing the effectiveness of their MS rehabilitation program. For each case, clinicians identified areas that were important to assess and various factors deemed important for OM selection. Criteria were established and used to assist in OM selection. In both cases, the described processes narrowed the selection of OMs and assisted with choosing the most appropriate ones. The recommendations, in addition to the processes described in these two cases, can be used by clinicians in any setting working with patients with MS across the disability spectrum.

Rhythmic cued motor imagery and walking in people with multiple sclerosis: a randomised controlled feasibility study

BACKGROUND

Novel physiotherapy approaches such as motor imagery and rhythmic auditory stimulation have been shown to improve walking in people with multiple sclerosis (MS). Rhythmic cued motor imagery was used in this study, whose objectives were to evaluate the feasibility of a larger randomised controlled trial (RCT) in people with MS and to obtain information on walking.

METHODS

Thirty adult people with MS who scored 1.5-4.5 on the Expanded Disability Status Scale were recruited at the MS Clinic Innsbruck, Austria. Participants were randomly allocated to one of three groups, all receiving usual care: 17 min of motor imagery, six times per week, for 4 weeks, with music (A) or metronome cues (B) and (C) controls. Primary outcomes were recruitment rates, retention, compliance, adverse events and fatigue (Modified Fatigue Impact Scale). Secondary outcomes were walking speed (Timed 25-Foot Walk) and walking distance (6-Minute Walk Test).

RESULTS

We achieved our recruitment target by recruiting 12 participants per month, a mean eligibility rate of 40.1 % (95 % confidence interval (CI) 35.8, 44.6 %) out of 2500 MS Centre patients, mean consent rate of 15.9 % (95 % CI 11.3, 21.7 %) plus 54.5 % (95 % CI 47.4, 61.4 %) of eligible patients who expressed their interest to participate. Retention of 100 %, no adverse events, good compliance, high acceptability of the interventions and no worsening of fatigue confirmed feasibility. The mean improvement in walking speed in both groups A and B was -0.9 s (95 % CI -1.3, -0.5), and mean worsening in group C was 0.4 s (95 % CI -0.3, 1.1). The mean improvement in walking distance in group A was 68.1 m (95 % CI 51.4, 84.7) and in group B 92.9 m (95 % CI 55.2, 130.5), and mean worsening in group C was -9.4 m (95 % CI -35.6, 16.9).

CONCLUSIONS

Results from our study showed that a full-scale RCT is feasible to investigate the effects of rhythmic cued motor imagery on walking in people with MS, with no changes to the interventions and assessments. Based on the walking improvements, a total sample size of 138 participants was calculated. Stratified blocked randomisation, allocation concealment and blinding will be used in the main study.

TRIAL REGISTRATION

ISRCTN: ISRCTN67054113.

Longitudinal relationships among posturography and gait measures in multiple sclerosis

OBJECTIVE

Gait and balance dysfunction frequently occurs early in the multiple sclerosis (MS) disease course. Hence, we sought to determine the longitudinal relationships among quantitative measures of gait and balance in individuals with MS.

METHODS

Fifty-seven ambulatory individuals with MS (28 relapsing-remitting, 29 progressive) were evaluated using posturography, quantitative sensorimotor and gait measures, and overall MS disability with the Expanded Disability Status Scale at each session.

RESULTS

Our cohort's age was 45.8 ± 10.4 years (mean ± SD), follow-up time 32.8 ± 15.4 months, median Expanded Disability Status Scale score 3.5, and 56% were women. Poorer performance on balance measures was related to slower walking velocity. Two posturography measures, the anterior-posterior sway and sway during static eyes open, feet apart conditions, were significant contributors to walk velocity over time (approximate R(2) = 0.95), such that poorer performance on the posturography measures was related to slower walking velocity. Similarly, the anterior-posterior sway and sway during static eyes closed, feet together conditions were also significant contributors to the Timed 25-Foot Walk performance over time (approximate R(2) = 0.83).

CONCLUSIONS

This longitudinal cohort study establishes a strong relationship between clinical gait measures and posturography. The data show that increases in static posturography and reductions in dynamic posturography are associated with a decline in walk velocity and Timed 25-Foot Walk performance over time. Furthermore, longitudinal balance measures predict future walking performance. Quantitative walking and balance measures are important additions to clinical testing to explore longitudinal change and understand fall risk in this progressive disease population.

Relationships between quantitative spinal cord MRI and retinal layers in multiple sclerosis

OBJECTIVE

To assess relationships between spinal cord MRI (SC-MRI) and retinal measures, and to evaluate whether these measures independently relate to clinical disability in multiple sclerosis (MS).

METHODS

One hundred two patients with MS and 11 healthy controls underwent 3-tesla brain and cervical SC-MRI, which included standard T1- and T2-based sequences and diffusion-tensor and magnetization-transfer imaging, and optical coherence tomography with automated segmentation. Clinical assessments included visual acuity (VA), Expanded Disability Status Scale, MS functional composite, vibration sensation threshold, and hip-flexion strength. Regions of interest circumscribing SC cross-sections at C3-4 were used to obtain cross-sectional area (CSA), fractional anisotropy (FA), perpendicular diffusivity (λ⊥), and magnetization transfer ratio. Multivariable regression assessed group differences and SC, retinal, and clinical relationships.

RESULTS

In MS, there were correlations between SC-CSA, SC-FA, SC-λ⊥, and peripapillary retinal nerve fiber layer (pRNFL) (p = 0.01, p = 0.002, p = 0.001, respectively) after adjusting for age, sex, prior optic neuritis, and brain atrophy. In multivariable clinical models, when SC-CSA, pRNFL, and brain atrophy were included simultaneously, SC-CSA and pRNFL retained independent relationships with low-contrast VA (p = 0.04, p = 0.002, respectively), high-contrast VA (p = 0.06, p = 0.008), and vibration sensation threshold (p = 0.01, p = 0.05). SC-CSA alone retained independent relationships with Expanded Disability Status Scale (p = 0.001), hip-flexion strength (p = 0.001), and MS functional composite (p = 0.004).

CONCLUSIONS

In this cross-sectional study of patients with MS, correlations exist between SC-MRI and retinal layers, and both exhibit independent relationships with clinical dysfunction. These findings suggest that the SC and optic nerve reflect ongoing global pathologic processes that supplement measures of whole-brain atrophy, highlighting the importance of combining measures from unique compartments to facilitate a thorough examination of regional and global disease processes that contribute to clinical disability in MS.

Relationship between foot vibration threshold and walking and balance functions in people with Multiple Sclerosis (PwMS)

The aim of this study was to investigate the relationship between foot vibration threshold and walking and balance functions in people with Multiple Sclerosis (PwMS). The study sample consisted of 34 participants with mean age of 49.5 years (SD 11.13). Participants were able to walk independently or with an assistive device. Participants underwent vibration threshold testing using the Neurothesiometer (NT), followed by the 6 min walking test (6MWT), the Timed Up and Go test (TUG) and the Berg balance scale (BBS). We found a statistically significant relationship between foot vibration threshold and all outcome measures used. The first metatarsophalangeal joint had the strongest correlation with BBS (-0.585, p < 0.01), 6 MWT (-0.557, p < 0.01) and TUG (0.498, p < 0.01). We also found that vibration threshold scores differed between those people with MS with and without walking limitations (Mann-Whitney U test, p < 0.01 for all testing points). In conclusion, these findings confirm the relationship between foot vibration threshold and clinical measures of walking and balance in PwMS and add to literature predictive validity of foot vibration threshold. They also suggest that vibration threshold may be important to consider when identifying people in need of intervention or when evaluating the effect of rehabilitation and exercise interventions.

The impact of dynamic balance measures on walking performance in multiple sclerosis

BACKGROUND

Static posture imbalance and gait dysfunction are common in individuals with multiple sclerosis (MS). Although the impact of strength and static balance on walking has been examined, the impact of dynamic standing balance on walking in MS remains unclear.

OBJECTIVE

To determine the impact of dynamic balance, static balance, sensation, and strength measures on walking in individuals with MS.

METHODS

Fifty-two individuals with MS (27 women; 26 relapsing-remitting; mean age = 45.6 ± 10.3 years; median Expanded Disability Status Scale score = 3.5) participated in posturography testing (Kistler-9281 force plate), hip flexion, hip extension, ankle dorsiflexion strength (Microfet2 hand-held dynamometer), sensation (Vibratron II), and walk velocity (Optotrak Motion Analysis System). Analyses included, Mann-Whitney, Spearman correlation coefficients, and multiple regression.

RESULTS

All measures were abnormal in individuals with MS when compared with norms (P < .05). Static balance (eyes open, feet together [EOFT]), anterior-posterior (AP) dynamic sway, and hip extension strength were strongly correlated with walking velocity (AP sway r = 0.68; hip extension strength r = 0.73; EOFT r = -0.40). Together, AP dynamic sway (ρr = 0.71; P < .001), hip extension strength (ρr = 0.54; P < .001), and EOFT static balance (ρr = -0.41; P = .01) explained more than 70% of the variance in walking velocity (P < .001).

CONCLUSIONS

AP dynamic sway affects walking performance in MS. A combined evaluation of dynamic balance, static balance, and strength may lead to a better understanding of walking mechanisms and the development of strategies to improve walking.

Spinal cord normalization in multiple sclerosis

BACKGROUND

Spinal cord (SC) pathology is common in multiple sclerosis (MS), and measures of SC-atrophy are increasingly utilized. Normalization reduces biological variation of structural measurements unrelated to disease, but optimal parameters for SC volume (SCV)-normalization remain unclear. Using a variety of normalization factors and clinical measures, we assessed the effect of SCV normalization on detecting group differences and clarifying clinical-radiological correlations in MS.

METHODS

3T cervical SC-MRI was performed in 133 MS cases and 11 healthy controls (HC). Clinical assessment included expanded disability status scale (EDSS), MS functional composite (MSFC), quantitative hip-flexion strength ("strength"), and vibration sensation threshold ("vibration"). SCV between C3 and C4 was measured and normalized individually by subject height, SC-length, and intracranial volume (ICV).

RESULTS

There were group differences in raw-SCV and after normalization by height and length (MS vs. HC; progressive vs. relapsing MS-subtypes, P < .05). There were correlations between clinical measures and raw-SCV (EDSS:r = -.20; MSFC:r = .16; strength:r = .35; vibration:r = -.19). Correlations consistently strengthened with normalization by length (EDSS:r = -.43; MSFC:r = .33; strength:r = .38; vibration:r = -.40), and height (EDSS:r = -.26; MSFC:r = .28; strength:r = .22; vibration:r = -.29), but diminished with normalization by ICV (EDSS:r = -.23; MSFC:r = -.10; strength:r = .23; vibration:r = -.35). In relapsing MS, normalization by length allowed statistical detection of correlations that were not apparent with raw-SCV.

CONCLUSIONS

SCV-normalization by length improves the ability to detect group differences, strengthens clinical-radiological correlations, and is particularly relevant in settings of subtle disease-related SC-atrophy in MS. SCV-normalization by length may enhance the clinical utility of measures of SC-atrophy.

Between-rater reliability of the 6-minute walk test, berg balance scale, and handheld dynamometry in people with multiple sclerosis

This study investigated the between-rater reliability of the Berg Balance Scale (BBS), 6-Minute Walk test (6MW), and handheld dynamometry (HHD) in people with multiple sclerosis (MS). Previous studies that examined BBS and 6MW reliability in people with MS have not used more than two raters, or analyzed different mobility levels separately. The reliability of HHD has not been previously reported for people with MS. In this study, five physical therapists assessed eight people with MS using the BBS, 6MW, and HHD, resulting in 12 pairs of data. Data were analyzed using intraclass correlation coefficients (ICCs), Spearman correlation coefficients (SCCs), and Bland and Altman methods. The results suggest excellent agreement for the BBS (SCC = 0.95, mean difference between raters [d̄] = 2.08, standard error of measurement [SEM] = 1.77) and 6MW (ICC = 0.98, d̄ = 5.22 m, SEM = 24.76 m) when all mobility levels are analyzed together. Reliability is lower in less mobile people with MS (BBS SCC = 0.6, d̄ = -1.83; 6MW ICC = 0.95, d̄ = 20.04 m). Although the ICC and SCC results for HHD suggest good-to-excellent reliability (0.65-0.85), d̄ ranges up to 17.83 N, with SEM values as high as 40.95 N. While the small sample size is a limitation of this study, the preliminary evidence suggests strong agreement between raters for the BBS and 6MW and decreased agreement between raters for people with greater mobility problems. The mean differences between raters for HHD are probably too high for it to be applied in clinical practice.