tDCS on Working Memory (WM) in Adults With ASD
Condition: Autism Spectrum Disorder
MeSH terms: Autism Spectrum Disorder
Study type: Interventional

Summary: 
      This study will involve an experiment in individuals with Autism Spectrum Disorder (ASD)
      comparing their performance on a working memory task before, during and after non-invasive
      brain stimulation (tDCS) compared to a control group in a 3x3 factorial design. How the
      stimulation affects performance on the task will be assessed, along with the impact of the
      intervention on the individuals.
    

Detailed description: 
      Many studies have examined working memory in people with autism spectrum disorder as working
      memory deficits in individuals with autism spectrum disorder leads to multiple difficulties
      associated with behaviour regulation, cognitive flexibility, abstract thinking, and focusing
      and sustaining attention. Evidence suggests that transcranial Direct Current Stimulation on
      the left dorsolateral prefrontal cortex leads to an increase in working memory performance in
      typically developing individuals. This may have important benefits for people with autism
      spectrum disorder since autism spectrum disorder is known to be associated with working
      memory deficiencies. This study will build on a pilot study conducted in 2014, the experiment
      tested participants working memory scores on an N-back test, after receiving anodal (positive
      stimulation) stimulation for 15 minutes over the left dorsolateral prefrontal cortex. This
      task requires the participant to perform multiple cognitive operations, including encoding of
      new stimuli, updating and maintaining past stimuli, and recognising and responding to whether
      each new stimulus matches the three-back stimulus. Participants are presented with a random
      set of ten letters (from A-Z). A different letter will be displayed every 2s, participants
      will be required to respond (key press 1) if the presented letter was the same as the letter
      presented three stimuli previously (a target). If it was not a target, participants were
      required to respond with key press 2. In this test, a total of 30 correct responses are
      possible. Participants will perform the task three times to reduce variability. Accuracy
      (number of correct responses), error rate (number of incorrect responses), and reaction time
      (interval between target presentation and pressing 1 or 2) will be recorded. Based on the
      findings from the pilot study, a full study will be conducted to investigate the effects of
      anodal transcranial Direct Current Stimulation on adults with high-functioning autism, as
      well as test whether the effects of transcranial Direct Current Stimulation on dorsolateral
      prefrontal cortex is dependent on polarity (anodal versus cathodal (negative stimulation)
      stimulation).
    

Intervention name(s): Transcranial direct current stimulation (tDCS)
Intervention type(s): Device
Intervention description(s): Transcranial Direct Current Stimulation (tDCS, a form of non-invasive brain stimulation) on the left dorsolateral prefrontal cortex (DLPFC)
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Each participant will receive the same 3 kinds of transcranial stimulation. However, the order in which they receive them will be randomly allocated.
Masking: Single (Participant)
Primary purpose: Supportive Care
Keywords: Transcranial Stimulation; Memory