The objective of the Cognitive Restructuring in ADHD: Functional Training (CRAFT) study is to develop a non-pharmacological intervention program for children with Attention Deficit Hyperactivity Disorder (ADHD). ADHD is a childhood onset clinical disorder of inattention, hyperactivity, and impulsivity. The present study will investigate the validity, feasibility and efficacy of this novel intervention.

This study will consist of a pre-post design and will include three phases. Participants will be tested individually at SickKids at baseline and post-training, the training phase will take place at the participants' respective homes. Each participant's parent will complete a demographic/medical questionnaire. The cognitive and behavioural outcome measures of interest in this study will be the following:

Planning and Organization: Tower Test from the Delis-Kaplan Executive Function System (D-KEFS; Delis et al, 2001) is a test of planning and problem solving abilities. Participants are asked to construct towers of discs on a set of pegs corresponding to a model. Raw scores reflect the participant's ability to use the fewest possible moves to achieve the tower depicted in the model.

Response Inhibition: Inhibitory control will be measured using the Stop Signal Task (SST). The SST measures the ability to cancel an already initiated motor response. The primary outcome measure will be the participants' mean stop signal reaction time (SSRT).

Inattentive and Hyperactivity Behaviour: Items associated with inattentiveness and hyperactivity from the Swanson, Nolan and Pelham Teacher and Parent Rating Scale version 4 (SNAP IV) will be used to estimate behavioural symptoms associated with ADHD.

Academic Performance: Academic efficiency and accuracy will be assessed using the fluency measures from the Woodcock Johnson III (WJ III) test of achievement.

Spatial Span: The spatial span item from the Wechsler Intelligence Scale for Children (WISC) will be used to estimate the child's visuo-spatial span. The primary outcome measure will be the number of correctly recalled spatial locations.

Working Memory: Working Memory will be tested using Spatial N-back 0,1,2.

Phase 1: Baseline Session

Children and their parents will participate in a 2 hour clinic session at SickKids. During this appointment, investigator/research staff will assess children's cognitive performances. The cognitive measures have been selected based on the range of processes commonly impaired in children with ADHD which will also be targeted by Mega Team. Both the training group and the control group will complete the same assessment battery. Tasks and questionnaires that will be included in this battery are;

• Spatial Span (working memory)
• WJ III
• Tower Test (D-KEFS)
• SST
• SNAP
• Demographic/Medical questionnaire
• Spatial N-back 0,1,2

Spatial Working Memory has been shown to be impaired in ADHD. In this task, the experimenter will point to a sequence of spatial locations on a grid and children will be required to reproduce this sequence in a forward or backward order. The length of sequences will vary between sets of 2-7. The spatial span tasks will be scored based on the Spatial Span scoring rules and norms (WISC-IV Integrated).

Academic efficiency and accuracy will be assessed using the fluency measures from the Woodcock Johnson III (WJ III) test of achievement. Participants will complete the reading fluency, math fluency and writing fluency subtests using alternate forms A and B in each assessment period to prevent retesting bias. This battery has been selected to be included in this study to provide objective measures of academic performance in areas where children with ADHD often show weakness (Czamara et al., 2013, Greven et al.,2013, Schmiedeler and Schneider, 2013).

Tower Test (DKEFS subtest (Delis et al., 2001) is a test of planning and problem solving abilities. Planning and organizational deficits have been reported in children with ADHD (Grodzinsky and Diamond, 1992, Mataro et al., 1997, Wilcutt et al., 2005) and will be targeted by Mega Team. Participants will be asked to construct towers of discs on a set of pegs corresponding to a model. Raw scores reflecting the participant's ability to use the fewest possible moves to achieve the tower depicted in the model.

The Stop Signal Test (SST) is a measure of response inhibition. Difficulties of response inhibition in ADHD have been reported by 82% of studies that have examined it. Response inhibition has been posited as an endophenotype for ADHD and shown to distinguish a group of children with ADHD from one with ADHD symptoms and one with conduct disorder. In the SST, participants will perform a choice reaction time task and will be instructed to respond as quickly and accurately as possible. On a portion of trials (e.g. 25%) a stop signal (a tone) will be presented and participants will be required to restrain their motor response. The delay between the go stimulus (the primary task) and the onset of the stop signal varies to determine the participant's ability to stop an already initiated motor response. This individualized stopping latency varies as a function of impulsivity. The stop-signal reaction time (SSRT) provides a measure of the ability to inhibit an already initiated response.

The SNAP-IV parent 18-item Rating Scale is a standardized scale that measures symptoms associated with ADHD. This provides the opportunity to identify the child's behavioural issues relative to standardized norms. This measure includes the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) criteria for ADHD with items 1-9 representing the inattentive subset of symptoms and items 10-18 representing the Hyperactivity/Impulsivity subset. Parents will be requested to fill out this scale at baseline, during training and post-training.

Spatial N-back 0,1,2 - The N-Back task requires on-line monitoring, updating, and manipulation of remembered information and measures key processes within working memory. In the N-Back task, the participant is required to monitor a series of stimuli and to respond whenever a stimulus is presented that is the same as the one presented n trials previously, where n is a pre-specified integer, usually 0, 1, or 2. The current study will use spatial location (spatial) paradigms.

Phase 2: the Training Sessions

In this phase, children in the treatment group will train at home on a computer with internet connection. They will be instructed to practice Mega Team for 30-35 minutes a day, approximately 5 days a week for a minimum of 21 sessions and a maximum of 25 sessions. The minimum value of 21 sessions has been selected based on findings of prior research. Majority of studies have been able to capture significant training-induced improvements after 21 sessions. The maximum training session of 25 days has been set to control for variability within and between our groups.

Performance on Mega Team will automatically upload to a secure website which will be monitored by the experimenters for both compliance and data analyses purposes. For example, research staff will know how often and how long the participants trained on Mega Team. One of the major objective of this study is to design a training program that is inherently engaging to children so that it will be easier to comply with the training schedule. It is possible that the presence of certain comorbid conditions such as ODD will affect adherence. However, the goal is to avoid compliance issues by ensuring that Mega Team is game-like and interesting to all children.

Children in the control group will play video-games as usual. Participants' parent/guardian in both groups (Treatment, Control) will be asked to complete a video game usage log weekly to record the type and duration of video game playing. Parents of both groups will also be required to fill out the SNAP-IV parent 18-item questionnaire once a week during the training phase. This questionnaire will provide a measure of change in behaviour.

Phase 3: the Post-Training Session

Following the completion of the training, families from both the treatment and the control groups will be scheduled for another 2 hour clinic session. The time between the completion of training and post-training appointment will range between 2-7 days. At this appointment, families will be asked to complete the same tasks and questionnaires that were administered to them during the baseline session. In this session, children will also be asked to fill out the Video-game Questionnaire. At the end of the post-training visit participants in the control group will be sent home with access to the Mega Team game for the same duration as the treatment group.

Inclusion Criteria:

• Subject is between 6-12 years old
• Subject has a diagnosis of Attention Deficit Hyperactive Disorder
• Subject is a previous POND baseline study (Attention Deficit Hyperactive Disorder Cognitive deficit and syndrome definition) participant.
• Parent/legal guardian and subject are willing to consent/assent to participate in this study

Exclusion Criteria:

• IQ below 80 on both verbal and performance scales of the Wechsler Intelligence Scale for children (WISC)-IV/V or Wechsler Abbreviated scale of intelligence (WASI II)
• History of psychosis, schizophrenia or other major mental health diagnosis that will prevent participation/completion of the protocol
• Subject's current medical problems that would preclude his/her participation in the study
• Child younger than 6 years old or older than 12
• Parent/legal guardian and/or subject not willing to consent/assent to participate in this study

de-identified data will be shared with our sponsor/funders- Ontario Brain Institute and ehave.