The Effects of Methylphenidate and Non-invasive Brain Stimulation on Inhibitory Control in Children With ADHD
Condition: Attention Deficit Hyperactivity Disorder
MeSH terms: Hyperkinesis; Attention Deficit Disorder with Hyperactivity
Study type: Interventional

Summary: 
      The aim of this study is comparing the effects of non-pharmacological intervention
      (transcranial Direct Current Stimulation, tDCS) with those of drug (methylphenidate, MPH)
      administration in children and adolescents with ADHD.

      The investigators hypothesized that tDCS would improve inhibitory control and visuo-spatial
      working memory as well as MPH.
    

Detailed description: 
      A sham controlled within-subjects study design will be conducted. Clinical eligibility
      screening will be completed at baseline. All participants will undergo an extensive
      neuropsychiatric evaluation in which developmental neuropsychiatrists and psychologists will
      evaluate the cognitive and the adaptive level, the severity of ADHD symptoms, and the
      presence of comorbid psychiatric disorders. After completing baseline assessment (T0),
      participants will be exposure to 3 conditions with an intersession-interval of 24h (T1, T2,
      T3): A) a single administration of 1 milliampere (mA) anodal tDCS session over the
      dorsolateral prefrontal cortex (DLPFC); B) a single administration of 1 mA sham tDCS session
      over the DLPFC; C) a single administration of immediate release MPH (Ritalin®), in accordance
      with the National Institute for Clinical Excellence (NICE) guidelines for ADHD (NICE, 2000).
      The order of the conditions will be counterbalanced across participants. After recruitment,
      the participants will be assigned to one of the 6 possible combinations of conditions (ABC,
      ACB, BAC, BCA, CBA, or CAB). The assignment will be according to a randomization order
      generated by a computer. The randomization information will be maintained by an independent
      researcher until data collection is completed. Participants will be tested on inhibitory
      control, by the Stop Signal Task (SST) and on working memory, by the N-Back Task, at baseline
      (T0), during tDCS administration (after 10 minutes of anodal and sham conditions) and after 1
      hour of MPH administration. To verify that carry-over effects will not occur, the SST and the
      N-Back Task will be performed before each session (T1, T2, T3) and results will be compared
      with those obtained at baseline (T0). If the participant will not return to baseline level,
      another evaluation will be administered at least after two hours and, again, until
      participant's performance will return to baseline. Participants and parents will be blinded
      to tDCS conditions allocation. The tDCS will be carried out with a BrainStim stimulator.
    

Intervention name(s): Methylphenidate; anodal tDCS; sham tDCS
Intervention type(s): Drug; Device; Device
Intervention description(s): A single dose of 5-10 mg of immediate release MPH (Ritalin®) will be administered in line with NICE and AIFA (Agenzia Italiana del Farmaco) guidelines for ADHD treatment.; Anodal electrode will be positioned over the left dlPFC, according to the 10-20 EEG on the sites corresponding F3, whereas the reference electrode will be placed above the contralateral supraorbital area, corresponding to Fp2. In the active tDCS condition, the current will increase slowly during the first 30 seconds to 1 mA (ramp-up) and, at the end of the stimulation, the current will decrease slowly to 0 mA during the last 30 seconds (ramp-down). Between the ramp-up and ramp-down constant current will be delivered for 20 minutes, with a density of 0.04 mA/cm2.; In the sham tDCS condition, the stimulation will be delivered by using the same active tDCS montage, respectively left-anodal dlPFC and right-reference electrode over Fp2. Stimulation intensity will be set at 1 mA, but the current will be applied for 30 seconds and will be ramped down without the participants' awareness.
Other intervention name(s): Ritalin
Intervention MeSH terms: Methylphenidate
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Study participants will receive the three conditions in random order:
a single dose of immediate release MPH (Ritalin®) administered according to the AIFA and NICE guidelines for ADHD;
a single 1 mA anodal tDCS session over the DLPFC for 20 min
a single session of sham tDCS over the DLPFC for 30s at the beginning and end of the tDCS session.
The order of administration of the conditions will be counterbalanced between the participants and the conditions will be spaced apart from an interval of 24 hours.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: methylphenidate; executive functions; working memory; tDCS; inhibitory control