Table 1 Means and methods to support information transfer

Previously, we and others discussed that combining the classic methods of written information and verbal explanation increases the child’s understanding [23, 70] and that these methods should be used in such a way as to supplement each other [23, 39]. We also suggested the use of other techniques, e.g. pictures. However, merely adding pictures to written information does not seem to increase understanding and additional research is required to optimize communication techniques [71].

One way to improve information provision is the use of stories and/or characters that children are familiar with. This can be helpful in explaining even difficult subjects. Harry Potter or the X-men, for example, can be used to explain genetics and hereditability [72]. Another suggestion is to shape the assent procedure as an activity [58, 73]. This way children truly become part of the research discussion and it seems a promising method to engage them in a way that appeals to them. Examples are creating a storyboard and playing word games as a way to discuss research [58]. Technical innovations can also be used, particularly since present-day children have grown up with multimedia. Although one study showed an increased comprehension of study procedures and risks among children who received multimedia information [74], a review on the improvement of understanding of informed consent elements for adults concluded that multimedia interventions often fail [75]. Moreover, one small study showed that generally children preferred written information sent to them individually, instead of being informed through websites or email [60]. Hence, more research is needed on how to use technological innovations and multimedia effectively. When using multimedia, at least two points need to be considered. First, multimedia can be implemented in a passive form, for example showing a DVD, and/or an active form, for example a computer game. Second, multimedia should not be considered a substitute for interaction between researcher and child [73].