Cumulative and Booster Effects of Multisession Prefrontal Transcranial Direct Current Stimulation in Adolescents with ASD

For active-tDCS condition, participants will receive stimulation on the dorsolateral prefrontal cortex with ramp up and ramp down mode for 10 seconds, eliciting a tingling sensation on the scalp that fades over seconds. Following that, a twenty-minute executive functional training task will be initiated five minutes subsequent to the stimulation mode, and the stimulation will be terminated when the training task ends.

For sham-tDCS condition, participants will receive initial stimulation with ramp up and ramp down mode for 30 seconds, eliciting a tingling sensation on the scalp then it will be discontinued. Participants will also receive the twenty-minute executive functional training task five minutes subsequent to the stimulation mode.

Participants will complete an online cognitive training program consisting of 10 consecutive daily weekday training sessions while they receive either the active or sham tDCS stimulation. Each training session will last for 20 minutes. The online cognitive training program will comprise five exercises assessing information processing speed and executive function capacities. Each exercise will take approximately 4 minutes to complete. Given many studies, across different neurological/neuropsychiatric diagnoses, especially for people with autism, it has long been established that social skills and functioning are closely related, and multiple studies have shown that executive function training can improve social functioning in autism or vice versa (i.e. social skills training improves executive functioning in autism), it is reasonable to include cognitive training in this tDCS protocol.