The influence of transcranial alternating current stimulation (tACS) on acquisition of second language vocabulary and increasing working memory capacity

Background and Aim : Nowadays in most societies, learning different language has become a challenge for people. Also there is widespread attention and interest in second language acquisition and roll of working memory as construct used in cognitive psychology. The aim of this study was to investigate effectiveness of transcranial alternating current stimulation (tACS) on acquisition of second language vocabulary and increasing working memory capacity.Methods : This was a single session study with three groups: real Theta tACS group (n=22), sham/verum Theta tACS group (n=16) and control group (n=18). For both real and sham groups we calculated individual Theta frequency (ITA) for tACS. We have placed active electrode on the right frontal (target electrode = F4) and reference one on parietal (target electrode = P4) brain areas (two return electrode above the right ear). We used N-back working memory test and German word list task (a task that has been designed by authors) before and one week after one session ITA tACS. The German word list contains of 30 words that selected from German applied words.Results : The results showed that one session ITA tACS could improve recalls of second language words after one week in real ITA tACS group comparing to Sham and control groups. However, we could not found any significant differences in working memory after ITA tACS.Conclusion : It seems that ITA tACS can increase learning capacity for second language and if use this protocol for more than one session could be more effective.

Keywords:

working memory , tACS , second language