gazzaley is now working to build a better, more interactive version of neuroracer that the f.d.a. could approve as a therapy for a.d.h.d. but that pathway could take years or decades to complete and until then, gazzaley says he can't make any strong recommendations for the use of cognitive training. >> we do need better, more carefully controlled studies in order to make really strong prescriptive advice. that being said, in general i think if you find these games fun, at least there's no clear evidence that they have detrimental effects so i usually don't disrecommend them. ( cash register ) >> i think the proof will be in the pudding. it's not going to happen to me now while i'm in my 50s, but if i'm still able to do stuff like this in my 80s i'll be thrilled. >> reporter: by then, in thirty years, who knows what science will tell us about how middle- aged people like wolff can keep their minds sharp. but with five million americans suffering from alzheimer's disease today, and with that number due to rise sharply in the coming decades, those solutions can't come soon enough. >>