Hey there! Thanks for all the questions- I'll follow up more thoroughly on Monday when I have some time.
I completely understand the desire for having a game that works 100%, and we are hoping to release our P300 tool in the next couple weeks so people can try it out and send us technical help questions (so you are ahead of the curve!). I may try to put together a 'releasable' example as well, so developers can get an idea of what might be a good way to structure the P300 (depending on my workload though!).
I briefly looked at the prototype, and just wanted to share some quick thoughts. First- I think it looks great! I can't speak for all the centers involved regarding what our audience's ages actually are (there will be 2 other hospitals besides the one I work at who we have partnered with who have BCI participants who will be our judges), but we definitely have a range of participants. As such, I am glad to have a game that is targeted towards the younger side of the population!
There are two main concepts which jumped out to me from your prototype which could benefit in using the P300. (Also working on some general videos to release so that these ideas can be explained a bit more from a different perspective!).
- In any of the given selection periods, if you can have a 'count-down' cue prior to the selection time, it helps participants focus and know that a 'selection' period in the game will be coming. So just having some instructions saying "Get ready and look at the cross!" or something akin to that, followed by a count down before the selection time would help a lot.
- Similar to 1- if you are randomly changing the choices, have a set number of 'times' that each choice flashes to break up the start and end sequence of the selection point. So for the characters, maybe highlight each character 10 times. Then have a break before the next 'selection' part begins. This helps on the engineering back-end as well, as we know when to start looking for the P300 response. Does that make sense?
I hope those help for the moment, and I'll answer all the other main questions more thoroughly soon! Glad to have your enthusiasm:).