Long-term TENS treatment decreases cortical motor representation in multiple sclerosis

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.

Electrical Stimulation of Muscle: Electrophysiology and Rehabilitation

The generation of action potentials in intramuscular motor and sensory axons in response to an imposed external current source can evoke muscle contractions and elicit widespread responses throughout the nervous system that impact sensorimotor function. The benefits experienced by individuals exposed to several weeks of treatment with electrical stimulation of muscle suggest that the underlying adaptations involve several physiological systems, but little is known about the specific changes elicited by such interventions.

Intensity-dependent clinical effects of an individualized technology-supported task-oriented upper limb training program in Multiple Sclerosis: A pilot randomized controlled trial

BACKGROUND

Task-oriented training promotes functional recovery in Multiple Sclerosis (MS). Know-how to determine an individualized training intensity and intensity-dependent effects are, however, unknown. The objective of the study was to investigate the feasibility and the clinical effects of a task-oriented upper limb training program at different individualized training intensities with conventional occupational therapy.

METHODS

People with MS (n = 20, EDSS range 4-8) were divided into three groups, receiving task-oriented training at 100% (n = 7) or 50% (n = 8) of their individual maximal number of repetitions, or conventional occupational therapy (n = 5). Effects were evaluated using different upper limb capacity and perceived performance measures on activity level, and measures on body functions and structures level.

RESULTS

Mixed model analyses revealed significant improvements (p < 0.05) over time on the Box and block test (BBT), Action Research Arm Test and the Manual Ability Measure-36. Significant interaction effects (group*time) in favor of the task-oriented group training at the highest intensity were found for BBT and static fatigue index during a maximal sustained handgrip strength test.

CONCLUSION

All participants were able to perform the task-oriented training at their individualized intensity without any adverse effects. Several improvements over time were found for all intervention groups, however the results suggest a superiority of task-oriented training at 100%. CLINICAL TRIAL REGISTRATION NUMBER ON CLINICALTRIALS.GOV: = NCT02688231.

Intrinsic functional plasticity of the sensorimotor network in relapsing-remitting multiple sclerosis: evidence from a centrality analysis

Background and Purpose

Advanced MRI studies have revealed regional alterations in the sensorimotor cortex of patients with relapsing-remitting multiple sclerosis (RRMS). However, the organizational features underlying the relapsing phase and the subsequent remitting phase have not been directly shown at the functional network or the connectome level. Therefore, this study aimed to characterize MS-related centrality disturbances of the sensorimotor network (SMN) and to assess network integrity and connectedness.

Methods

Thirty-four patients with clinically definite RRMS and well-matched healthy controls participated in the study. Twenty-three patients in the remitting phase underwent one resting-state functional MRI, and 11 patients in the relapsing-remitting phase underwent two different MRIs. We measured voxel-wise centrality metrics to determine direct (degree centrality, DC) and global (eigenvector centrality, EC) functional relationships across the entire SMN.

Results

In the relapsing phase, DC was significantly decreased in the bilateral primary motor and somatosensory cortex (M1/S1), left dorsal premotor (PMd), and operculum-integrated regions. However, DC was increased in the peripheral SMN areas. The decrease in DC in the bilateral M1/S1 was associated with the expanded disability status scale (EDSS) and total white matter lesion loads (TWMLLs), suggesting that this adaptive response is related to the extent of brain damage in the rapid-onset attack stage. During the remission process, these alterations in centrality were restored in the bilateral M1/S1 and peripheral SMN areas. In the remitting phase, DC was reduced in the premotor, supplementary motor, and operculum-integrated regions, reflecting an adaptive response due to brain atrophy. However, DC was enhanced in the right M1 and left parietal-integrated regions, indicating chronic reorganization. In both the relapsing and remitting phases, the changes in EC and DC were similar.

Conclusions

The alterations in centrality within the SMN indicate rapid plasticity and chronic reorganization with a biased impairment of specific functional areas in RRMS patients.