Modulatory effects of transcranial direct current stimulation (tDCS) on words and non-words reading task

TITLE: Modulatory effects of transcranial direct current stimulation (tDCS) on words and non-words reading task AUTHOR(S): Margherita Forgioneb, Patrizio Tressoldi b, Daniela Mapelli b, Paulo Sergio Boggio a a Centro de Ciências Biológicas e da Saúde, Universidade Presbiteriana Mackenzie, Sao Paulo b Dipartimento di Psicologia Generale, Università degli Studi di Padova, Italia INTRODUCTION: 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 these studies was to investigate the role of left and right posterior temporal cortex in words and non-words reading process, through tDCS. We focused on the online task to see if it can influence the subjects’ performance. We hypothesized that the anodal stimulation would facilitate the task execution compared to sham and cathodal, in terms of reaction times and accuracy. METHOD: 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 words and non-words, before and after stimulation. RESULTS: Regarding reaction times, we found significant effect of cathodal tDCS in short words reading task. Similarly, we also found an improvement in reading accuracy for non-words after tDCS. The online task doesn’t seem to affect the performance. CONCLUSIONS: We found a modulatory effect of cathodal tDCS in words reading task, suggesting a compensatory mechanisms of the right hemisphere. To verify this hypothesis, we are investigating different montages, involving left or right hemisphere. Further studies are necessary to understand the modulation effects of this technique, in addition with other methodologies, such as eye tracker, and with clinical sample, in particular dyslexics.