The Effect of Transcranial Direct Current Stimulation on Theory of Mind and Metacognition in Adults with Autism Spectrum Disorder

Individuals with Autism Spectrum Disorder experience difficulties with social skills, which can be attributed to deficits in Theory of Mind (ToM, the ability to infer others thoughts) and metacognitive abilities (thinking about your own thinking). Neuroimaging studies have revealed that the medial prefrontal cortex is part of the ToM and metacognitive networks, and is underactive in individuals with Autism. The purpose of this study was to investigate whether transcranial Direct Current Stimulation (tDCS) would temporarily improve ToM and metacognitive performance. In a double-blind, randomised design, 15 adults with Autism attended two research sessions, 1 week apart, where they received active (20 minutes of 1mA anodal tDCS to the medial prefrontal cortex) or sham tDCS before completing tasks that assessed their ToM and metacognitive ability. Paired-samples t-tests revealed that active tDCS did not improve ToM or metacognitive ability. However, further analysis revealed interactions between tDCS type and tDCS order, for some of the tasks. We cannot conclude whether anodal tDCS improves or worsens performance on ToM tasks but it seems likely that under some circumstances active tDCS can improve metacognitive ability. Future research is needed to further explore the impact of tDCS on the medial prefrontal cortex in order to aid the development of new therapies for individuals with