Overview
Repetitive behaviors (RBs) are a prevalent feature of Autism Spectrum Disorder (ASD). There are two groups of RBs: lower-order (e.g. motor stereotypies) and higher-order RBs (e.g. restricted interests), linked to sensory-motor and the associative loops, respectively. To date, treatment options for RBs are very limited. High-definition transcranial direct current stimulation (HD-tDCS) may be effective in reducing the impact of RBs in children with ASD by targeting the associated brain alterations. Moreover, the high focality of HD-tDCS will help the investigators to disentangle the relative contribution of different brain loops (namely, sensory-motor and the associative loops) into RBs subtypes. The investigators will also study the electrophysiological patterns associated to behavioral changes after the application of HD-tDCS.
Description
The experimental design will be the following: randomized, three-arm, between subject, double blind, and placebo-controlled.
Children and adolescents with ASD will be selected and randomly assigned to three groups: 1. Active high-definition tDCS (HD-tDCS) over pre-SMA; 2. Active high-definition tDCS (HD-tDCS) left DLPFC; 3. Sham high-definition tDCS (HD-tDCS).
In this project, the investigators will work to understand whether a brain-based intervention, with the use of HD-tDCS can enhance RBs in individuals with ASD.
The protocol will allow the investigators to:
- Test if Active high-definition tDCS (HD-tDCS) compared to sham HD-tDCS will contribute in reducing RBs
- Test if HD-tDCS over pre-SMA cortex will decrease lower-order RBs, while HD-tDCS over dlPFC will decrease higher-order RBs
- Test if the Active Groups will significantly improve in the remaining psychological measures compared to the Sham Group
- Test if the Active Groups will change in the RBS-R total score will be significantly correlated with changes in neuropsychological and electroencephalographic (EEG) connectivity measures
- Test if the Active Groups will change in the RBS-R total score will be significantly correlated with changes in the remaining psychological measures and parental stress.
The overarching goal is to provide a scientific foundation for devising new rehabilitation strategies in ASD.
Eligibility
Inclusion Criteria:
- participants of both genders with ASD diagnosis according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and based on clinical evaluation and administration of gold standard tools for ASD diagnosis
- an intelligence quotient (IQ) higher or equal to 70 (IQ ≥ 70)
- age range from 8 years to 13 years and 11 months included
Exclusion Criteria:
- the presence of neurological/medical/genetic conditions (i.e., brain tumours or genetic syndromes)
- personal or family history of epilepsy
- other primary psychiatric diagnoses (i.e., bipolar disorders, schizophrenia spectrum disorders, or adjustment disorder)
- sensorimotor deficits
- the presence of peacemaker or other metal devices in the body;
- ongoing CNS-active drug treatment
- receiving other cognitive-behavioral therapies specifically focused on RBs in the 3 months before the study