Noninvasive neuromodulation for rehabilitation of sensorimotor function and reduction of chronic pain

Abstract

Objectives People with motor disorders or chronic pain demonstrate plateaued improvements despite compliance with therapy and willing to improve daily life quality. This limitation may result from brain maladaptive plasticity (pathways, maps). Therefore, noninvasive neuromodulation, via painless repetitive magnetic stimulation of brain or muscles, is tested in research to influence brain mechanisms that favor recovery. But no consensus yet is proposed about the most efficient protocols. The talk focuses on the need to individualize the approach, i.e., to adapt neurostimulation protocols owing to individual factors (e.g., lesion or pain severity and side, balance of hemispheric activity, pathways integrity). Methods The research breakthroughs in collaboration with clinicians are illustrated by data in chronic stroke, cerebral palsy, traumatic brain injury, immobilization (learned non-use), Parkinson's disease, chronic low back pain, complex regional pain syndrome. The respective influence of brain and peripheral neurostimulation on clinical outcomes has been related to brain plasticity (markers of the primary motor cortex (M1) function: M1 excitability, structural reserve, factors predictive of success). Results Studies suggest that protocols of neurostimulation should be case-specific and adapted to the intertwined influences of M1 excitability imbalance, corticospinal integrity (M1 structural reserve for rehabilitation) and lesion or pain side (dominant, non-dominant). Neurostimulation systematically improved responsiveness to subsequent therapy and the persistence of changes has been related to sessions repetition, combination with therapy, and cognitive integrity. Conclusion Further efforts are warranted to adapt neuromodulation/neurostimulation protocols per patient owing to neuroplastic changes that favor vs. hinder improvement of function. A sole solution for all cases is not suggested. An individualized approach relying on biomarkers and clinical outcomes should ease the implementation in clinical practice of noninvasive neuromodulation as an innovative therapeutic option to speed-up recovery towards gains beyond those already reached, thus to further improve the quality of life.