Preserved brain functional plasticity after upper limb task‐oriented rehabilitation in progressive multiple sclerosis

Hand functioning in progressive multiple sclerosis improves with tDCS added to daily exercises: A home-based randomized, double-blinded, sham-controlled clinical trial

BACKGROUND

Many individuals with progressive multiple sclerosis (PMS) are challenged by reduced manual dexterity and limited rehabilitation options. Transcranial direct current stimulation (tDCS) during motor training can improve rehabilitation outcomes. We developed a protocol for remotely supervising tDCS to deliver sessions of stimulation paired with training at home.

OBJECTIVE

This study evaluated the effectiveness of at-home tDCS paired with manual dexterity training for individuals with PMS.

METHODS

Sixty-five right-hand dominant participants with PMS and hand impairment were randomized to receive either active or sham M1-SO tDCS paired with manual dexterity training over 4 weeks. Clinical outcomes were measured by the changes in Nine-Hole Peg Test (9-HPT) and Dellon-Modified-Moberg-Pick-Up Test (DMMPUT).

RESULTS

The intervention had high rates of adherence and completion (98% of participants completed at least 18 of 20 sessions). The active tDCS group demonstrated significant improvement for the left hand compared with baseline in 9-HPT (-5.85 ± 6.19 vs -4.23 ± 4.34, p = 0.049) and DMMPUT (-10.62 ± 8.46 vs -8.97 ± 6.18, p = 0.049). The active tDCS group reported improvements in multiple sclerosis (MS)-related quality of life (mean increase: 5.93 ± 13.04 vs -0.05 ± -8.27; p = 0.04).

CONCLUSION

At-home tDCS paired with manual dexterity training is effective for individuals with PMS, with M1-SO tDCS enhancing training outcomes and offering a promising intervention for improving and preserving hand dexterity.

Brain neuroplasticity in multiple sclerosis patients in functional magnetic resonance imaging studies. Part 2: Effect of aerobic training

Purpose

The aim of this study was to evaluate the effects of aerobic training on motor cortical areas in multiple sclerosis (MS) patients, based on task-based functional magnetic resonance imaging (t-fMRI) as well as on brain activity at rest, according to resting state functional MRI (rs-fMRI) studies.

Material and methods

Multiple sclerosis patients were divided into 2 groups consisting of 14 participants each: the MS study group and the MS control group. All MS patients underwent clinical assessment and MRI examination, twice: in the MS study group at the time of inclusion in the study and after a 4-week period of aerobic training, whereas in the MS control group it happened at the time of inclusion and after a period of one month without exercise rehabilitation. The MRI study protocol included rs-fMRI and t-fMRI sequences, which were the grounds for an analysis of resting state networks (RSN) as well as peak level and cluster level parameters within motor cortex areas - the primary motor cortex, premotor area, and supplementary motor area, respectively.

Results

In the MS study group, aerobic training improved the clinical condition and decreased the functional correlation between the sensorimotor network and the salience network. Also, significant decreases of the mean cluster level (72.42 vs. 38.35) and peak level values (10.89 vs. 7.64) were observed in the contralateral primary motor cortex in this group of patients between examinations.

Conclusions

Aerobic training not only improves physical performance but also contributes to changes in brain activity - both within RSN and motor cortex areas in MS patients.

Advanced neuroimaging techniques to explore the effects of motor and cognitive rehabilitation in multiple sclerosis

INTRODUCTION

Progress in magnetic resonance imaging (MRI) technology and analyses is improving our comprehension of multiple sclerosis (MS) pathophysiology. These advancements, which enable the evaluation of atrophy, microstructural tissue abnormalities, and functional plasticity, are broadening our insights into the effectiveness and working mechanisms of motor and cognitive rehabilitative treatments.

AREAS COVERED

This narrative review with selected studies discusses findings derived from the application of advanced MRI techniques to evaluate structural and functional neuroplasticity modifications underlying the effects of motor and cognitive rehabilitative treatments in people with MS (PwMS). Current applications as outcome measure in longitudinal trials and observational studies, their interpretation and possible pitfalls and limitations in their use are covered. Finally, we examine how the use of these techniques could evolve in the future to improve monitoring of motor and cognitive rehabilitative treatments.

EXPERT COMMENTARY

Despite substantial variability in study design and participant characteristics in rehabilitative studies for PwMS, improvements in motor and cognitive functions accompanied by structural and functional brain modifications induced by rehabilitation can be observed. However, significant enhancements to refine rehabilitation strategies are needed. Future studies in this field should strive to implement standardized methodologies regarding MRI acquisition and processing, possibly integrating multimodal measures. This will help identifying relevant markers of treatment response in PwMS, thus improving the use of rehabilitative interventions at individual level. The combination of motor and cognitive strategies, longer periods of treatment, as well as adequate follow-up assessments will contribute to enhance the quality of evidence in support of their routine use.

Physical fitness moderates the association between brain network impairment and both motor function and cognition in progressive multiple sclerosis

BACKGROUND

Neurodegeneration leads to continuous accumulation of disability in progressive Multiple Sclerosis (MS). Exercise is considered to counteract disease progression, but little is known on the interaction between fitness, brain networks and disability in MS.

OBJECTIVE

The aim of this study to explore functional and structural brain connectivity and the interaction between fitness and disability based on motor and cognitive functional outcomes in a secondary analysis of a randomised, 3-month, waiting group controlled arm ergometry intervention in progressive MS.

METHODS

We modelled individual structural and functional brain networks based on magnetic resonance imaging (MRI). We used linear mixed effect models to compare changes in brain networks between the groups and explore the association between fitness, brain connectivity and functional outcomes in the entire cohort.

RESULTS

We recruited 34 persons with advanced progressive MS (pwMS, mean age 53 years, females 71%, mean disease duration 17 years and an average walking restriction of < 100 m without aid). Functional connectivity increased in highly connected brain regions of the exercise group (p = 0.017), but no structural changes (p = 0.817) were observed. Motor and cognitive task performance correlated positively with nodal structural connectivity but not nodal functional connectivity. We also found that the correlation between fitness and functional outcomes was stronger with lower connectivity.

CONCLUSIONS

Functional reorganisation seems to be an early indicator of exercise effects on brain networks. Fitness moderates the relationship between network disruption and both motor and cognitive outcomes, with growing importance in more disrupted brain networks. These findings underline the need and opportunities associated with exercise in advanced MS.

The correlation between 9-HPT and patient-reported measures of upper limb function in multiple sclerosis: a systematic review and meta-analysis

Upper limb function is one of the most affected domains in people with multiple sclerosis (PwMS), as self-reported by 50% of patients. Heterogeneous results have been found about the correlation between objective and subjective upper limb function. The aim of the present study is to perform a systematic review and meta-analysis of studies presenting data on the strength of association between the gold standard for 9-Hole Peg Test scores and Patient-Reported Outcome Measures (PROMs) of manual ability. Primary research studies including assessments of 9-Hole Peg Test scores and Patient-Reported Outcome Measures were searched in Scopus, Web of Science, and PubMed. Meta analytical calculations were performed using a random-effects model. We retrieved n = 27 studies including n = 75 distinct effect sizes (N of subjects = 3263). The central tendency analysis showed a strong correlation between 9-HPT scores and PROMs (r = 0.51, 95% CI [0.44, 0.58]). Moderator analysis showed the effect size to be significantly larger in studies with a mean or median EDSS level indicating severe disability. The publication bias hypothesis was not supported; instead, we noted that studies based on larger samples also tend to report stronger effect sizes. Results of the study indicate that the correlation between 9-HPT and PROMs is strong, although the constructs measured by these instrument does not fully overlap. The correlation between 9-HPT and PROMs was stronger in larger studies and when samples include a sizeable subgroup of PwMS with severe disability, pointing out the importance of sample diversity.

Upper Limb Sensory-Motor Control During Exposure to Different Mechanical Environments in Multiple Sclerosis Subjects With No Clinical Disability

Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease resulting in motor impairments associated with muscle weakness and lack of movement coordination. The goal of this work was to quantify upper limb motor deficits in asymptomatic MS subjects with a robot-based assessment including performance and muscle synergies analysis. A total of 7 subjects (MS: 3 M−4 F; 42 ± 10 years) with clinically definite MS according to McDonald criteria, but with no clinical disability, and 7 age- and sex-matched subjects without a history of neurological disorders participated in the study. All subjects controlled a cursor on the computer screen by moving their hand or applying forces in 8 coplanar directions at their self-selected speed. They grasped the handle of a robotic planar manipulandum that generated four different environments: null, assistive or resistive forces, and rigid constraint. Simultaneously, the activity of 15 upper body muscles was recorded. Asymptomatic MS subjects generated less smooth and less accurate cursor trajectories than control subjects in controlling a force profile, while the end-point error was significantly different also in the other environments. The EMG analysis revealed different muscle activation patterns in MS subjects when exerting isometric forces or when moving in presence of external forces generated by a robot. While the two populations had the same number and similar structure of muscle synergies, they had different activation profiles. These results suggested that a task requiring to control forces against a rigid environment allows better than movement tasks to detect early sensory-motor signs related to the onset of symptoms of multiple sclerosis and to differentiate between stages of the disease.

Neuroplasticity and Motor Rehabilitation in Multiple Sclerosis: A Systematic Review on MRI Markers of Functional and Structural Changes

Background: Motor rehabilitation is routinely used in clinical practice as an effective method to reduce progressive disability gain in multiple sclerosis (MS), but rehabilitation approaches are typically unstandardized, and only few studies have investigated the impact of rehabilitation on brain neuroplasticity. Objective: To summarize and critically analyze studies applying MRI markers of functional connectivity and structural changes to assess the effect of motor rehabilitation on brain neuroplasticity in MS. Methods: Literature search was performed using PubMed and EMBASE, selecting studies having as a subject motor rehabilitation and advanced MRI techniques investigating neuroplasticity in adult patients affected by MS. Results: Seventeen out of 798 papers were selected, of which 5 applied structural MRI (4 diffusion tensor imaging, 1 volumetric measurements), 7 applied functional fMRI (5 task-related fMRI, 2 resting-state fMRI) whereas the remaining 5 applied both structural and functional imaging. Discussion: The considerable data heterogeneity and the small sample sizes characterizing the studies limit interpretation and generalization of the results. Overall, motor rehabilitation promotes clinical improvement, paralleled by positive adaptive brain changes, whose features and extent depend upon different variables, including the type of rehabilitation approach. MRI markers of functional and structural connectivity should be implemented in studies testing the efficacy of motor rehabilitation. They allow for a better understanding of neuroplastic mechanisms underlying rehabilitation-mediated clinical achievements, facilitating the identification of rehabilitation strategies tailored to patients' needs and abilities.

Differentiation among bio- and augmented- feedback in technologically assisted rehabilitation

Introduction: In rehabilitation practice, the term 'feedback' is often improperly used, with augmented feedback and biofeedback frequently confused, especially when referring to the human-machine interaction during technologically assisted training. The absence of a clear differentiation between these categories represents an unmet need for rehabilitation, emphasized by the advent of new technologies making extensive use of video feedback, exergame, and virtual reality.Area covered: In this review we tried to present scientific knowledge about feedback, biofeedback, augmented feedback and neurofeedback, and related differences in rehabilitation settings, for a more proper use of this terminology. Despite the continuous expansion of the field, few researches clarify the differences among these terms. This scoping review was conducted through the searching of current literature up to May 2020, using following databases: PUBMED, EMBASE and Web of Science. After literature search a classification system, distinguishing feedback, augmented feedback, and biofeedback, was applied.Expert opinion: There is a need for clear definitions of feedback, biofeedback, augmented feedback, and neurofeedback in rehabilitation, especially in the technologically assisted one based on human-machine interaction. In fact, the fast development of new technologies requires to be based on solid concepts and on a common terminology shared among bioengineers and clinicians.

Rehabilitation in multiple sclerosis in 2021

Patients with multiple sclerosis, despite advances in therapy, often suffer from locomotor impairment that limits their mobility and affect quality of life. Rehabilitation is part of the treatment of MS and has shown its beneficial effects in numerous studies. While traditional rehabilitation techniques remain in the limelight, new technologies are emerging and make it possible to improve the management of disabling symptoms. The aim of this update is to synthesize the new therapy techniques proposed in rehabilitation for patients with multiple sclerosis according to the symptoms as balance, gait, upper limb disorders, fatigue, spasticity and disease progression published over the past 5 years. With regard to balance and walking disorders, neuromotor rehabilitation, physical exercise, rhythmic auditory stimulation, gait robot training and exergaming are effective. Only physical exercise has shown a positive effect on fatigue management. Spasticity is improved by classic rehabilitation techniques however non-invasive brain stimulation are promising. The rehabilitation of upper limb dysfunctions uses various effective techniques such as the repetition of functional tasks in real or virtual situations. In case of a more severe disability, arm robots can be used to relearn the impaired movement. Action observation training in real or virtual situations is also effective. Finally, under certain conditions the constraint induced movement therapy is proposed. The effects of rehabilitation are not only positive on the pyramidal symptoms and fatigue but also increase neuroplasticity and perhaps a neuroprotective effect as shown in some studies.

Rhythmic Auditory Stimulation as an Adjuvant Therapy Improved Post-stroke Motor Functions of the Upper Extremity: A Randomized Controlled Pilot Study

OBJECTIVES

To explore whether rhythmic auditory stimulation (RAS) could improve motor functions of post-stroke hemiparetic upper extremity.

DESIGN

A prospective, randomized controlled, assessor-blinded pilot study.

METHODS

Thirty stroke patients were randomly distributed into the RAS group (n = 15) and the control group (n = 15). Both groups received regular therapies. The RAS group received additional 30 min of RAS training, while the control group received additional 30 min of regular therapies for 5 days per week for 4 weeks. The Fugl-Meyer Assessment-Upper Extremity (FMA-UE), Wolf Motor Function Test (WMFT), and Barthel Index (BI) were used. The co-activation interval and co-contraction index were calculated from surface electromyography (sEMG) recordings on the affected biceps and triceps during elbow flexion and extension. Assessments were performed before and after the treatments.

RESULTS

Significant improvements in motor functions were observed within both groups (p < 0.05 in the FMA-UE, WMFT, and BI, respectively), as well as between groups after the treatments (higher scores in the RAS group, all p < 0.05 except for p = 0.052 in the FMA-UE; group × time interaction, all p < 0.05). Statistical significance was found in the co-activation interval between groups after the treatments (lower in the RAS group; p = 0.022 during elbow extension; p = 0.001 during elbow flexion; group × time interaction, p < 0.05 only during elbow extension). No statistical significance was found in the co-contraction index between groups; an inversed pattern of changes was observed between groups supported by relatively higher increments in the triceps recruitments to the biceps.

CONCLUSION

Using RAS in task-oriented exercises was effective in moderating co-contraction, facilitating task-oriented movements of the hemiparetic upper extremity, and improving ADLs among those who had emerging isolated joint movements. The effects were evident on sEMG possibly by adjusting the balance of recruitments between the agonist and the antagonist.

CLINICAL TRIAL REGISTRATION

The study was registered at the Chinese Clinical Trial Registry (No. 1900026665).