The impact of prefrontal transcranial direct current stimulation (tDCS) on theory of mind, emotion regulation and emotional‐behavioral functions in children with autism disorder: A randomized, sham‐controlled, and parallel‐group study

Abstract

Advances in our knowledge about the neuropsychological mechanisms underlying core deficits in autism spectrum disorder (ASD) have produced several novel treatment modalities. One of these approaches is modulation of activity of the brain regions involved in ASD symptoms. This study examined the effects of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (DLPFC) on autism symptom severity, theory of mind, emotion regulation strategies, and emotional‐behavioral functions in children with ASD. Thirty‐two children (Mage = 10.16, SD = 1.93, range 7–12 years) diagnosed with ASD were randomly assigned to active (N = 17) or sham stimulation (N = 15) groups in a randomized, sham‐controlled, parallel‐group design. Participants underwent 10 sessions of active (1.5 mA, 15 min, bilateral left anodal/right cathodal DLPFC, 2 sessions per week) or sham tDCS. Autism symptom severity, theory of mind, emotion regulation strategies, and emotional‐behavioral functioning of the patients were assessed at baseline, immediately after the intervention, and 1 month after the intervention. A significant improvement of autism symptom severity (i.e., communication), theory of mind (i.e., ToM 3), and emotion regulation strategies was observed for the active as compared to the sham stimulation group at the end of the intervention, and these effects were maintained at the one‐month follow‐up. The results suggest that repeated tDCS with anodal stimulation of left and cathodal stimulation of right DLPFC improves autism symptom severity as well as social cognition and emotion regulation in ASD. Lay Summary Previous research has suggested that targeting core mechanisms underlying cognitive‐emotional and behavioral deficits of autistic children might improve symptoms of ASD. Deficient social and behavioral functioning, impaired theory of mind, and emotional regulation deficits have been identified as core treatment targets for this group. Specific subregions of the prefrontal cortex are involved in these deficits, including hypoactivity of the dorsolateral prefrontal cortex (DLPFC). Upregulation of this area with non‐invasive brain stimulation, namely anodal transcranial direct current stimulation (tDCS), results in improved social and behavioral functioning in children with ASD. Very few studies have however examined the effects of this intervention on theory of mind, emotional regulation, and emotional‐behavioral problems. We examined the effects of anodal tDCS over the left DLPFC (F3), combined with cathodal tDCS over the right DLPFC (F4) on autism symptom severity as well as theory of mind, emotional regulation, and emotional‐behavioral problems of children with ASD. This intervention improved autism symptom severity, specific domains of theory of mind, and emotion regulation. These findings have clinical implications for the treatment of ASD and suggest that targeting core mechanisms underlying socio‐cognitive‐emotional deficits of autistic children using tDCS might improve symptoms of ASD.

Safety of noninvasive brain stimulation in children

“…The intervention was safe, and only two adverse events occurred, including insomnia and irritability on the second night after tDCS in one case and feeling irritable all day in the evening of the second and third days after tDCS in the second case [58 && ]. In the next study, 10 sessions of anodal tDCS (1.5 mA, 15 min per session) in 32 children with autism resulted in no adverse event other than the common side effects during the stimulation and up to 1-month follow-up [59]. In another tDCS study conducted in 25 children with ADHD (12 sessions, 1 mA), the adverse effects were mild, but three children, all from the real tDCS group, experienced headaches, with two requiring temporary cessation and one requiring removal from the study [60].…”

A bibliometric analysis of global research status and trends in neuromodulation techniques in the treatment of autism spectrum disorder

“…It is worth noting that “transcranial direct current stimulation”, “double blind” and “adolescent” have been the most active burst keywords since 2019. In the past two years, clinical research on tDCS has mainly been carried out in children and adolescents with autism, and has played a positive role in the recovery of social functions [ 66 , 68 , 102 ]. This may reflect future research trends to a certain extent and may be related to the clinical trials in the treatment of adolescent psychiatric disorders by tDCS.…”

“…A recent study showed that DBS in the ventral forelimb of the internal capsule or medial forebrain bundle could reduce the symptoms of obsessive–compulsive behavior and depression, which indicates that neuromodulation techniques may be an effective intervention in the comorbidity of ASD, but further exploration is needed [ 135 ]. In addition, we found that some recent clinical studies predominantly focused on the positive effects of tDCS in adolescents with ASD, including social cognition and emotional behavior [ 66 , 68 , 102 ]. Working memory is often impaired in ASD, which may be the basis of the core defects of cognitive and social functions [ 136 ].…”

The use of noninvasive brain stimulation techniques in autism spectrum disorder

“…They observed superior effects of five and 20 sessions versus sham with the concurrent behavioral intervention, with no difference between 5 and 20 sessions (Auvichayapat & Auvichayapat, 2022). (Zemestani et al, 2022) conducted a randomized, sham‐controlled, and parallel‐group study of children 7–12 years old with ASD ( n = 17 and 15 in active and sham groups respectively). Participants received 10 sessions (15 min) of active or sham bilateral dlPFC (left anodal/right cathodal) stimulation over 5 weeks.…”