Participants
Mainstream primary schools in the northern region (Groningen area) of the Netherlands and the western region (Ghent area) of the Dutch-speaking part of Belgium were contacted by phone or letter and invited to join the study. Initial requirements for participation were (a) schools had enough computers with headphones for students to play the GraphoGame-NL intervention on a daily basis, (b) classroom teachers allowed students to play the game for 10 to 15 mins per day for at least seven weeks, (c) schools allowed trained clinicians to administer behavioural tests on site at school before and after the intervention during regular school hours, and (d) teachers agreed to adhere to their allocated gaming condition. Eight schools were willing and eligible to participate (three in the Netherlands, five in Belgium) with 16 classrooms (four in the Netherlands, 12 in Belgium). All 312 children attending these classrooms were eligible to participate in the study, of which 107 lived and went to school in the Netherlands, and 205 in Belgium. Subsequently, all parents of children from the selected classrooms were informed about the study and asked for their written informed consent for the gaming and additional behavioural tests. Children were asked for oral assent prior to assessment. To enable as many children as possible to play the game, there were no initial eligibility or exclusion criteria, and parents were also given the option to consent to participation without additional behavioural assessments. Parents (or caregivers) of participating children were asked to complete a questionnaire about their child’s handedness, language(s)/dialect(s) spoken at home, family history of reading problems, neurological problems, and medication.