Ankle dysfunction in multiple sclerosis and the effects on walking

Genomic analysis of mobility measures on 5-month-old gilts associated with structural soundness

Sow lameness results in premature culling, causing economic loss and well-being issues. A study, utilizing a pressure-sensing mat (GAIT4) and video monitoring system (NUtrack), was conducted to identify objective measurements on gilts that are predictive of future lameness. Gilts (N = 3,656) were categorized to describe their lifetime soundness: SOUND, retained for breeding with no detected mobility issues; LAME_SOW, retained for breeding and detected lame as a sow; CULL_STR, not retained due to poor leg structure; LAME_GILT, not retained due to visible signs of lameness; and CULL, not retained due to reasons other than leg structure. The GAIT4 system creates a series of measurements for each hoof and a lameness score (GLS) while NUtrack records animal movement and posture durations each day. To determine if measurements from the GAIT4 and NUtrack systems were associated with lifetime soundness, mixed model analyses were conducted in R including fixed effects of breed of sire, contemporary group and lifetime soundness score, and random effect of animal. A second mixed model was run without lifetime soundness score and estimates of animal effects were then used to conduct ssGBLUP analyses using three generations of pedigree and genotypes from ~50k SNP on > 60% of phenotyped animals. Genomic heritabilities were estimated, SNP effects were back-solved and significance was based on Bonferroni-corrected permutation tests. GAIT4 traits indicative of lameness (LAME_GILT and CULL_STR vs. SOUND; P < 0.05) were the standard deviation of GLS, average stride length, and average stance time, while significant NUtrack measurements were eating, standing, lateral lying, total lying, speed, distance, and rotations. In addition, rotations differed (P < 0.05) between SOUND vs. LAME_SOW and distance tended to be different (P < 0.10). Estimates of heritability for predictive NUtrack traits were ~0.3 and GAIT4 traits were ~0.2. There were 382 significant SNP effects in 47 genomic regions, four regions on chromosomes 1, 4, 11, and 14 accounted for over 60% of the associations. Genome-level imputed genotypes linked several regions with possible causative genes. Objective measurements from the GAIT4 and NUtrack systems at 5 mo of age were heritable, able to detect unsound animals, and were associated with lifetime soundness.

Cognitive-motor dual task to reveal gait impairments in multiple sclerosis patients at an early stage: A systematic review

BACKGROUND

Multiple sclerosis can cause locomotor and cognitive impairments even at lower levels of disability, which can impact daily life. The cognitive-motor dual task is commonly used to assess everyday locomotion. Thus, this study aimed to examine the effect of cognitive-motor dual tasks on gait parameters among patients with multiple sclerosis in the early disease stages and to determine whether dual tasks could be used as a clinical test to detect locomotion impairments.

METHODS

A systematic search of five databases was conducted in May 2024. The population of interest was patients with multiple sclerosis with an Expanded Disability Status Scale score of 4 or less. The following outcome measures were examined: spatiotemporal and kinematic parameters. The Newcastle-Ottawa Scale was used to assess the quality of the studies.

FINDINGS

Eleven studies including 270 patients with multiple sclerosis and 221 healthy controls. Three spatiotemporal parameters were modified both in patients with multiple sclerosis and healthy controls during dual-task performance: gait speed, stride length and the double support phase. No spatiotemporal parameter was affected during dual-task performance in patients with multiple sclerosis alone.

INTERPRETATION

Dual-task performance could be useful for assessing gait impairments in patients with multiple sclerosis provided that assessments and protocols are standardized. Nevertheless, the spatiotemporal parameters did not allow discrimination between patients with multiple sclerosis at an early stage and healthy controls. Three-dimensional gait analysis during dual-task performance could be a useful approach for detecting early gait impairments in patients with multiple sclerosis, assessing their progression and adjusting rehabilitation programs.

Propulsive Force Modulation Drives Split-Belt Treadmill Adaptation in People with Multiple Sclerosis

Most people with multiple sclerosis (PwMS) experience significant gait asymmetries between their legs during walking, leading to an increased risk of falls. Split-belt treadmill training, where the speed of each limb is controlled independently, alters each leg's stepping pattern and can improve gait symmetry in PwMS. However, the biomechanical mechanisms of this adaptation in PwMS remain poorly understood. In this study, 32 PwMS underwent a 10 min split-belt treadmill adaptation paradigm with the more affected (MA) leg moving twice as fast as the less affected (LA) leg. The most noteworthy biomechanical adaptation observed was increased peak propulsion asymmetry between the limbs. A kinematic analysis revealed that peak dorsiflexion asymmetry and the onset of plantarflexion in the MA limb were the primary contributors to the observed increases in peak propulsion. In contrast, the joints in the LA limb underwent only immediate reactive adjustments without subsequent adaptation. These findings demonstrate that modulation during gait adaptation in PwMS occurs primarily via propulsive forces and joint motions that contribute to propulsive forces. Understanding these distinct biomechanical changes during adaptation enhances our grasp of the rehabilitative impact of split-belt treadmill training, providing insights for refining therapeutic interventions aimed at improving gait symmetry.

The combined deleterious effects of multiple sclerosis and ageing on neuromuscular function

BACKGROUND

The prevalence of older (>60 years) people with multiple sclerosis (pwMS) is increasing. This introduces numerous challenges, as both MS and ageing independently contribute to the deterioration of neuromuscular function.

AIM

The aim was to compare the neuromuscular function in pwMS and healthy controls (HC) across three age groups: young, middle-aged, and old.

METHODS

Using a cross-sectional study design, the maximal muscle strength (Fmax) and rate of force development (RFD) of the knee extensors (KE) and plantar flexors (PF) were assessed using an isokinetic dynamometer. In addition, voluntary activation (VA) and resting twitch (RT) were measured using the interpolated twitch technique.

RESULTS

The Fmax, RFD, and VA of the KE were reduced in pwMS compared to HC across age groups. In pwMS, reductions were observed in PF Fmax, RFD, and RT, predominantly in the middle-aged and old age groups. Reductions increased with age in KE for both groups (except for VA) but in PF only for pwMS. The "trajectory" differed between pwMS and HC, as pwMS showed reductions from young to middle age, while HC showed reductions from middle to old age in KE.

CONCLUSION

The combined negative effects of MS and ageing on neuromuscular function were especially present in the PF but also substantial in the KE. RFD showed large deficits for pwMS compared to HC across age groups. The findings can partly be explained by a reduction in VA and RT, but further investigations of neural regulation are needed to explain large RFD deficits.

Kinematic Gait Analysis in People with Mild-Disability Multiple Sclerosis Using Statistical Parametric Mapping: A Cross-Sectional Study

Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system. Gait abnormalities, such as altered joint kinematics, are common in people with MS (pwMS). Traditional clinical gait assessments may not detect subtle kinematic alterations, but advances in motion capture technology and analysis methods, such as statistical parametric mapping (SPM), offer more detailed assessments. The aim of this study was to compare the lower-limb joint kinematics during gait between pwMS and healthy controls using SPM analysis. Methods: A cross-sectional study was conducted involving pwMS and healthy controls. A three-dimensional motion capture system was used to obtain the kinematic parameters of the more affected lower limb (MALL) and less affected lower limb (LALL), which were compared using the SPM analysis. Results: The study included 10 pwMS with mild disability (EDSS ≤ 3) and 10 healthy controls. The results showed no differences in spatiotemporal parameters. However, significant differences were observed in the kinematics of the lower-limb joints using SPM. In pwMS, compared to healthy controls, there was a higher anterior pelvis tilt (MALL, p = 0.047), reduced pelvis elevation (MALL, p = 0.024; LALL, p = 0.044), reduced pelvis descent (MALL, p = 0.033; LALL, p = 0.022), reduced hip extension during pre-swing (MALL, p = 0.049), increased hip flexion during terminal swing (MALL, p = 0.046), reduced knee flexion (MALL, p = 0.04; LALL, p < 0.001), and reduced range of motion in ankle plantarflexion (MALL, p = 0.048). Conclusions: pwMS with mild disability exhibit specific kinematic abnormalities during gait. SPM analysis can detect alterations in the kinematic parameters of gait in pwMS with mild disability.

Isokinetic Resistance Training for Ankle Plantarflexor Spasticity and Muscle Weakness in People With Multiple Sclerosis: A Proof-of-Concept Case Series

OBJECTIVE

To the best of the authors' knowledge, no data are available about the use of isokinetic resistance training for managing ankle plantarflexor spastic hypertonia in people with multiple sclerosis (MS). The aim of this proof-of-concept study was to explore the feasibility and effects of concentric contractions on spasticity-related resistance to passive motion, strength, and mobility in people with MS and ankle plantarflexor spasticity.

METHODS

In this pretest/posttest case series, 5 people with MS (mean age = 53.6 [SD = 8.8] years; median Expanded Disability Status Scale score = 5; Modified Ashworth Scale range = 1-4) received 6 weeks of isokinetic resistance training of the spastic plantarflexors. Before and after the intervention, the following outcomes were assessed: average peak torque during passive robotic mobilization, isometric strength, surface electromyography (sEMG) from the spastic muscles, time to complete the 10-m Walk Test, and the Timed "Up & Go" Test. The standardized effect size was used to test pretest and posttest effects at the individual level. Group-level analyses were also performed.

RESULTS

Following the training, the average peak torque recorded from the plantarflexors during passive motion at a velocity of 150 degrees per second was found to be decreased by at least 1 SD in all participants but 1, with a significant reduction at the group level of 23.8%. Conversely, no changes in sEMG activity were detected. Group-level analyses revealed that the maximal strength of the trained plantarflexors increased significantly (31.4%). Fast walking speed increased and time to complete the Timed "Up & Go" Test decreased in 4 participants, although not significantly at the group level.

CONCLUSION

Isokinetic resistance training proved safe and feasible in people who had MS and ankle plantarflexor spasticity. The observed reductions in resistance to passive motion from the spastic plantarflexors in the absence of sEMG changes might suggest a mechanical rather than a neural effect of the training.

IMPACT

Based on these preliminary findings, isokinetic resistance training does not exacerbate hypertonia in people with MS and ankle plantarflexor spasticity and could be safely used to manage muscle weakness in this population.