This game for SickKids Hospital in Toronto was an MRI stillness training game developed to reward stillness in a video game context.
Kids undergoing MRI scans must remain still. Movement greater than a few millimeters can spoil a scan due to blurriness. The result is that many kids then must undergo anesthesia which both is dangerous and costly.
Our game was designed to teach kids to stay still for a test period of 3 minutes with maximum motion of 4mm. The game used energetic onscreen characters that fall asleep over a period of time so long as you don't move. A small on-screen dot within a circle represents the users’ motion. If players remain still, the characters fall asleep one by one.
And it worked by the way! Players were able to achieve stillness with repeated play with long lasting effect.