My guess would be they're talking about the Nintendo DS, which has a number of "brain training" type games for it. I can think of at least 4 off the top of my head, and there's probably more.
MOST DS games can be controlled using the stylus and touch screen. So you don't necessarily need a surgeon's articulation, or that of a 12 year old kid.
And while I find it kind of difficult to look at the screen on my PSP for long periods of time, I don't have the same problem with my DS. The screen may be smaller, but things still generally seem bigger, and easier to see.
The one brain training game I've tried (Brain Age 2) on the DS has big buttons to press on the touch screen, and is controlled entirely by the stylus. There's also big boxes for entering in things like the basic arithmetic signs. I don't know how the others work, but I would suspect they're similar.
Some residents @ my mother's retirement/care facility have been bragging that a hand-held game player has helped them greatly increase their short-term memory capacity. (This is NOT the Wii increase in movement.) Have you investigated this? My concern is that the controller mechanism might be too small for less "articulate" hands or the screens may be too small for the impaired vision of the seniors. Could you please let me know what you may have found? Thanks, Sallie