Long-lasting improvement following tDCS treatment combined with a training for reading in children and adolescents with dyslexia

Noninvasive brain stimulation transiently modulates reading ability in individuals with dyslexia by facilitating the underactive neural pathways in them. However, its long-term effects have not been determined. This study confirmed the ameliorative effects of multiple sessions of transcranial direct current stimulation (tDCS) combined with a training for reading on the reading abilities of children and adolescents with dyslexia and examined whether they are long-lasting. Twenty-six children and adolescents with dyslexia received 3 20-min sessions per week for 6 weeks (18 sessions) of left anodal/right cathodal tDCS, set to 1 mA, over the parieto-temporal regions, combined with training for reading. The participants were randomly assigned to receive active or sham treatment. Reading measures (text, high- and low-frequency words, non-words) were recorded before and immediately after the treatment and 1 and 6 months later. The long-term tolerability to tDCS was also evaluated. The active group received long-lasting benefits in reading. Specifically, the non-word reading efficiency index improved at every time point, as did the low-frequency word reading efficiency index at 1 and 6 months after the end of the treatment. No differences emerged in the sham group. No long-term adverse effects were documented. This study provides evidence of persistent improvements in reading in children and adolescents with dyslexia, constituting a new rehabilitative approach for the remediation of dyslexia.