Upper limb motor training based on task-oriented exercises induces functional brain reorganization in patients with multiple sclerosis

Abstract

The aim of this work was to investigate changes in motor performance and in the brain activation pattern during finger movements, following upper limb motor training in multiple sclerosis. Thirty people with multiple sclerosis with mild upper limb sensorimotor deficits were randomly allocated to one of two groups: the experimental group (n = 15) received an upper limb treatment based on voluntary task-oriented movements; the control group (n = 15) underwent passive mobilization of shoulder, elbow, wrist and fingers. All participants completed three treatment sessions per week for eight weeks. Before and after the intervention, all participants were evaluated for motor performance by means of Action Research Arm Test, Nine Hole Peg Test, and grip strength by a dynamometer, and for brain activations by functional magnetic resonance imaging during right finger opposition movements. Similar effects on motor performance were found in the two groups. A significant improvement with time was found in both groups at NHPT and in GRIP strength; a similar trend was found at ARAT. However, only the experimental group showed increased lateralization towards more normal brain activation following treatment, with activation clusters mainly located in the left brain hemisphere and right cerebellum. In conclusion, both active and passive interventions were effective in improving motor performance. However, only the treatment based on voluntary task-oriented movements could induce changes in brain activity that may have reflected skill acquisition by the right hand, reducing the activation of compensatory areas and decreasing brain resource demand.

Keywords: fMRI; hemispheric lateralization; multiple sclerosis; upper limb motor training; voluntary movements.