Document Type : Research articles


1 Department of Physical Therapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran

2 Discipline of Physiotherapy, Department of Rehabilitation, Nutrition and Sport, School of Allied Health, La Trobe University, Bundoora, Melbourne, Australia

3 Department of Biostatistics, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran

4 Non-invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia


Background: Unihemispheric concurrent dual-site anodal transcranial direct current stimulation (a-tDCSUHCDS) of the primary mo- tor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) are introduced as effective techniques on M1 corticospinal excitability enhancement and its after-effects. Objectives: The current study aimed at investigating the potential effects of multiple sessions of a-tDCSUHCDS of M1-DLPFC on motor skills learning in healthy individuals.
Methods: The randomized, clinical trial was conducted on a total of 37 volunteers completed all sessions of the study and were randomly divided into two groups of a-tDCSUHCDS and sham stimulation by the block randomization method. The current study was performed from January to May 2017 in Iran. Participants attended daily 20-minute motor training sessions for three consecu- tive days, while they concurrently received a-tDCS. Motor skills were assessed before the intervention (day 1), immediately after the intervention (day 3), and one week after the completion of the intervention.
Results: A total of 37 participants were included in the data analysis. Immediately after the completion of the intervention on day 3, mean skills in the experimental and control groups were 0.33 and 0.30, respectively. One week after the completion of the interven- tion, mean skills in the experimental and control groups were 0.36 and 0.29, respectively. The trend of motor learning considerably increased in the experimental (0.17; P < 0.001) and control (0.11; P < 0.001) groups. No significant difference was observed in mo- tor learning immediately after the intervention between the groups           (P = 0.23), while there was a significant difference in long-term offline learning between the groups (P = 0.04).
Conclusions: Greater motor skills in the a-tDCSUHCDS group compared with the sham tDCS group at one-week retention indicated the robustness of the a-tDCSUHCDS effect.