To quote Bart Simpson. Looks like brain enhancement games is about as effective as… other technologies that claim to be able to enhance… less cerebral body parts. Not Exactly Rocket Science says:

You don’t have to look very far to find a multi-million pound industry supported by the scantiest of scientific evidence. Take “brain-training”, for example. This fledgling market purports to improve the brain’s abilities through the medium of number problems, Sudoku, anagrams and the like. The idea seems plausible and it has certainly made bestsellers out of games like Dr Kawashima’s Brain Training and Big Brain Academy. But a new study by Adrian Owen from Cambridge University casts doubt on the claims that these games can boost general mental abilities.

[To the tune of Suba, “Sereia,” from the album The Rough Guide To Brazilian Electronica (a 3-star song, imo).]