Present and future of Non-invasive Brain Stimulation for motor stroke recovery

Abstract

Approximately 1.1 million inhabitants of Europe suffer a stroke each year. Despite major improvements in primary prevention and acute treatment, stroke remains a devastating disease. More than 70% of stroke survivors experience insufficient functional recovery of their upper limb, resulting in diminished quality of life. Conventional therapies show limited results, therefore various innovative neurorehabilitation strategies are emerging in order to enhance beneficial plasticity and improve motor recovery. Among them, non-invasive brain stimulation (NIBS) provides safe and low cost tools to augment functional reorganization after stroke and facilitate motor recovery. Available NIBS techniques continue to expand, but repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) as noninvasive neuromodulatory therapies have been studied in stroke recovery. When combined with a training protocol, both techniques have been shown to improve motor functions in acute and chronic stroke patients, however recent results of meta-analyses on the benefits of treatment have been mixed. It is now obvious that the current use of NIBS is suboptimal. After summarizing the current NIBS approaches for motor stroke recovery, I will highlight the factors that limit its efficacy and reliability, hence preventing its widespread us in clinical settings. Then, I will mention potential markers that might help to classify stroke patients in order to individually identify the optimal therapy. I will discuss future methodological developments, which could pave the way pathophysiologically motivated strategies and patient-tailored precision medicine.