The mediatory effects of transcranial direct current stimulation (tDCS) on reading task

In recent past tDCS has gained much attention for rehabilitation purposes. Moreover, few studies have been conducted to investigate its efficacy on reading process. The aim of this study was to investigate the role of left and right posterior temporal cortex in words and non-words reading tasks, through tDCS. We investigated the effects of tDCS on subjects´ reading performance, in terms of reading times and accuracy, using different online tasks. Twenty good readers were tested in 3 sessions (sham, anodal, cathodal), with different online task (text reading or music listening). tDCS was applied bilaterally over posterior temporal lobe, with a current of 1,5 mA, lasting for 20 minutes. Participants had to read aloud words or non-words, before and after stimulation. We recorded reaction times and accuracy for each stimulus, before and after stimulation. We observed an improvement in terms of reaction times in short-word reading task and of accuracy for non-words after cathodal tDCS. However, the online task doesn’t seem to affect the performance. In conclusion, significant effect of cathodal tDCS in reading task, hints a compensatory mechanisms of the right hemisphere. To test the proposed hypothesis, we planned to investigate the effects of tDCS over different brain sites involving left or right hemisphere, to further understand the mediatory effects of stimulation in reading processes, particularly in dyslexia.