I thought that the results of the study showing that certain games can increase processing speed, which translates into an increased I.Q. score, was very exciting. I did some Googling on Silvia Bunge, the main researcher, and the work that's being done in Bunge's lab using brain scans to look at changes in the brain during certain cognitive activities, and it really is the sort of thing that will lead to meaningful interventions in the future to help kids and adolescents with all sorts of problems, including the type that Mo seems to have.
Those are the sorts of answers I think you'd like to hear from a neuropsychologist now--whether Mo's problems are neurologically based, and in what area(s) of the brain, and what sorts of interventions can improve functioning--but I don't think you can get those answers simply based on neuropsych testing at this stage of the game because this research is fairly new, and it involves brain scanning that's being done only for research and not in clinical practice. But, like the study Bunge did involving processing speed and playing certain games, it can suggest some immediate and practical interventions, like having Mo play those games. The next research step on Bunge's agenda would likely be to do brain scans while the games are played, or before and after a trial period of playing those games, to see what's actually going on in the brain.
So, even if a neuropsychologist can't answer the questions you have now, I think they might be able to do so in the near future based on the findings from such research. That's really hopeful stuff.
This article describes some of Bunge's other work--it's very interesting
Are you familiar with Mind Reading--a game designed to help children read social cues better?
I don't know anything about it, or it's effectiveness, I just came across it looking up things I thought might help Mo.
I wonder if something like this Magic Wand Keyboard would enable Mo to "write" more quickly and easily when using a computer, and thereby help to decrease some of his frustration and difficulty about expressing himself via the written word. Just a thought.
Since having to write something is probably mostly associated with schoolwork, I wonder if Mo would have the same level of difficulty with it if the writing occurred in a different context, like exchanging simple e-mails or messages with you--something that could be made more fun for him, less pressured, and something that wasn't going to be evaluated or graded. Or you might try exhanging brief hand written little notes on simple hand made greeting cards with each other.