Non Invasive Brain Stimulation Effects on Attentional Performance in ADHD Adults
Condition: Attention Deficit/Hyperactivity Disorder
MeSH terms: Hyperkinesis; Attention Deficit Disorder with Hyperactivity
Study type: Interventional

Summary: 
      This study aims to evaluate the effect of noninvasive brain stimulation in adults with ADHD
      symptomatology compared them with healthy adults. For this, volunteers will allocate into two
      groups (experimental and control), will pass through session two types of transcranial
      stimulation: Repetitive Transcranial MagneticsStimulation (rTMS) and transcranial direct
      current stimulation (tDCS); considering two session types (real and sham). Attentional
      assessment will be carried out through specific neurocognitive tests applied before and after
      each session of stimulation
    

Detailed description: 
      The sample will be divided into four groups: (i) Experimental tDCS; (ii) Experimental rTMS;
      (iii) tDCS control; and rTMS control. The experimental groups consisted of subjects with ADHD
      symptomatology. Control groups were formed by healthy individuals.

      The subject will be considered healthy when there was no diagnosis of any DSM-IV psychiatric
      disorder and had symptoms with ADHD when there were frequent presence of at least six
      symptoms of inattention and / or symptoms of hyperactivity/impulsivity described by the Adult
      Self Report Scale (ASRS), a reliable tool for diagnosis of attention deficit / hyperactivity
      and validated for the Brazilian population.

      Both groups underwent two sessions of cortical stimulation: real (rTMS or tDCS) and sham. The
      order of sessions will be randomized and there will be a minimum interval of at last one week
      between sessions.

      Experimental Sessions

      Repetitive Transcranial Magnetic Stimulation (rTMS) With the individual seated comfortable,
      rTMS will be applied through a magnetic stimulator (Neurosoft®) using a figure-8 coil,
      positioned on the scalp at an angle of 45 degrees from the midline and pointing toward the
      anterior region of the skull.

      The area stimulated will be the left dorsolateral prefrontal cortex (DLPFC). Before applying
      rTMS over the DLPFC will be necessary to map the area of the representation of the FID by
      applying single pulses to measure the motor evoked potential (MEP) and resting motor
      threshold (RMT). The intensity adopted in real rTMS session will be 80% of the RMT. rTMS will
      be applied in just one session divided in to 5 blocks of stimulation. Each block will be
      separated by 5 minutes intervals. In each block 15 rTMS series of 1-second duration at 10 Hz
      frequency were applied. The interval between sets will be 10 seconds. The sham stimulation
      will be applied with the same settings real rTMS, but the coil will be not coupled to the
      magnetic stimulator, so the individual will be not able to differentiate the real session of
      sham.

      Transcranial Direct Current Stimulation (tDCS) Individuals will be instructed to sit in a
      chair and get a comfortable position. The continuous electrical current will be applied
      through a microcurrent stimulator (Soterix, USA). The surface electrodes used in all sessions
      of this study have dimensions of 5x7cm (35 cm2), were composed of electrically conductive
      rubber and wrapped in sponges soaked in saline.

      For the application of tDCS, the anode will be positioned on DLPFC and cathode in the
      contralateral supraorbital region. Parameters of intensity and stimulation duration of the
      current used were previously established in humans: intensity 1mA and duration of 10 minutes.
      In sham stimulation, sessions will use the same procedures of real tDCS application, however
      the stimulation device will be switched off five seconds after the start.

      Outcome measures - The subjects will be submitted an evaluation before (t0) the application
      of non-invasive cortical stimulation (active and sham) and immediately after (t1). These
      assessments consisted of neurocognitive tests that assess cognitive function and attention
      span of the patients. The tests will be applied (i) Trail Making Test (part A and B); (ii)
      digit span (forward and reverse order); (iii) digit symbol; (iv) C; (v) D2. Thus, the
      following items were assessed: (i) attentional focus (digit symbol, AC and trail making-part
      A); (ii) maintaining the attentional focus (D2 test); (iii) attentional span (digit span
      forward); (iv) the ability of mental manipulation (digit span backward and trail making test-
      part B); (v) ability to resist interference (D2 test).

      Neuropsychological assessment will be performed by a neuropsychology, blind to the type of
      experimental session (rTMS / or active tDCS / sham) to which the subject was submitted.
    

Intervention name(s): Transcranial magnetic stimulation (Neurosoft®); Transcranial direct current stimulation (Soterix, USA)
Intervention type(s): Device; Device
Intervention description(s): Repetitive transcranial magnetic stimulation; Transcranial direct current stimulation
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary purpose: Other
Keywords: Neuromodulation Attention Deficit Hyperactivity Disorder