If you want an enormous, controlled, statistically-significant study that's been published in a high-quality, peer reviewed journal, check out this study of brain training software in Nature.

The finding is surprising.

The training experience that I have most appreciated is that of pushing my brain towards the state of flow, releasing any stress or rumination and constantly letting go of the attachment to the frustration of failure while also not being frustrated by the fact that I may be frustrated about failure. This has a strong overlap with the process involved in some forms of meditation and is certainly the kind of thing that I would expect to have generalized benefit - albeit not necessarily to one of an improvement on tests of general intelligence. The format of game with a score to be maximised invokes my rather strong competitive instincts and so rather more motivating than the abstract thought "I should do meditation because meditation is good for me'.

The abstract is insufficiently concrete and vague for me to tell whether their studies relate to directly to the kind of training that I am interesting. I would expect not - since my interest is in things that are rather hard to test! My curiosity is not quite sufficient for me to bipass the feeling of disgust and frustration at the paywall and round up the rest of the document

This seems to miss the point cousin_it was making.