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

Abstract

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.

Investigation of in-phase bilateral exercise effects on corticospinal plasticity in relapsing remitting multiple sclerosis: a multiple baseline design

“…Corticospinal plasticity is exercise-dependent (34,35) and influenced by various factors (36,37), such as aerobic exercise (22,(38)(39)(40), resistance training (22,40), as well as interlimb coordination (41,42). Previous studies that assessed corticospinal plasticity using TMS in healthy participants and in chronic stroke survivors, reported that interlimb coordination and especially inphase bilateral movement has the strongest effect on corticospinal plasticity (43)(44)(45)(46).…”

“…Motor symptoms in RRMS are associated with changes in corticospinal tract integrity and neuroplasticity (19)(20)(21)(22)(23)(24)(25). The corticospinal tract is one of the major motor descending pathways 4 providing voluntary motor function in humans (26).…”

Investigation of in-phase bilateral exercise effects on corticospinal plasticity in relapsing remitting multiple sclerosis: A registered report single-case concurrent multiple baseline design across five subjects

“…Corticospinal plasticity is exercise-dependent [ 32 , 33 ] and influenced by various factors [ 34 , 35 ], such as aerobic exercise [ 20 , 36 – 38 ], resistance training [ 20 , 38 ], as well as interlimb coordination [ 39 , 40 ]. Previous studies that assessed corticospinal plasticity using TMS in healthy participants and in chronic stroke survivors, reported that interlimb coordination and especially in-phase bilateral movement has the strongest effect on corticospinal plasticity [ 41 – 44 ].…”

Physical exercise in multiple sclerosis is not just a symptomatic therapy, it has a disease-modifying effect: Commentary

“…In addition to conducting such studies, a way forward may also include further development of relevant (fast-responding) functional brain outcomes that are sensitive to exercise. 6…”

“…In addition to conducting such studies, a way forward may also include further development of relevant (fast-responding) functional brain outcomes that are sensitive to exercise. 6 The many beneficial effects of exercise in MS implicate that it is already strongly recommended to people with MS. 7 Nevertheless, it is of utmost importance to both patients and health professionals to determine if exercise has disease-modifying effects, as this would offer a new supplementary treatment option almost free of side effects. As for the future, some cautious optimism does exist as a recent international initiative-Moving exercise research in MS forward (the MoXFo initiative)-has gathered more than 50 researchers aiming to accelerate discoveries in this field.…”