Motor stroke recovery after tDCS: a systematic review

The purpose of the present study was to investigate the effects of transcranial direct current stimulation (tDCS) on motor recovery in adult patients with stroke, taking into account the parameters that could influence the motor recovery responses. The second aim was to identify the best tDCS parameters and recommendations available based on the enhanced motor recovery demonstrated by the analyzed studies. Our systematic review was performed by searching full-text articles published before February 18, 2019 in the PubMed database. Different methods of applying tDCS in association with several complementary therapies were identified. Studies investigating the motor recovery effects of tDCS in adult patients with stroke were considered. Studies investigating different neurologic conditions and psychiatric disorders or those not meeting our methodologic criteria were excluded. The main parameters and outcomes of tDCS treatments are reported. There is not a robust concordance among the study outcomes with regard to the enhancement of motor recovery associated with the clinical application of tDCS. This is mainly due to the heterogeneity of clinical data, tDCS approaches, combined interventions, and outcome measurements. tDCS could be an effective approach to promote adaptive plasticity in the stroke population with significant positive premotor and postmotor rehabilitation effects. Future studies with larger sample sizes and high-quality studies with a better standardization of stimulation protocols are needed to improve the study quality, further corroborate our results, and identify the optimal tDCS protocols.