PLAY A VIDEO GAME DEVELOPED BY LUMOSITY, the leader in the “brain training” games movement, and you’ll find yourself solving equations and remembering patterns. The games are supposed to give you a cognitive boost, such as better mental performance at work and less memory decline as you age. But their claims of a fitter brain have not gone unchallenged, and were recently grounds for a $2 million fine for false advertising from the Federal Trade Commission.

Lumosity stands by its products, saying that their work is “at the forefront of a new and rapidly innovating field, which means there is a lot we don’t yet know.” But skepticism about what digital brain games can accomplish is nothing new among researchers and regulatory agencies. In October 2014, the Max Planck Institute for Human Development and the Stanford Center on Longevity issued a statement, signed by 69 scientists, which asserted that there was “no compelling scientific evidence” that such games could reduce or reverse cognitive decline.

One signature on the statement, however, appeared with an asterisk. Adam Gazzaley, who is a cognitive neuroscientist at the University of California, San Francisco, wanted to disclose a conflict of interest, as he and his lab are developing brain-training games of their own.

“My signing that letter was based on frustrations with overinflated marketing claims,” Gazzaley explains. “But I think the scientific field itself is robust. What we’ve learned about plasticity is exciting.”

Plasticity, or the ability of the brain to change and adapt, is something that Gazzaley believes can be measurably developed by means of playing digital games, if you can find both the right games and the right measures. In a 2013 study, his team showed that elderly subjects who played one of his games, NeuroRacer, for one month, improved their ability to multitask on the game to the level of 20-year-olds, and retained this ability six months later. They also improved significantly on untrained tests of sustained attention control and working memory, which is a key ability to process and juggle information.  An encephalogram done before and after training showed cognitive test improvement was accompanied by increased activation of the prefrontal cortex during game play. The work appeared on the cover of Nature, under the headline, “Game Changer.”

NeuroRacer has now become Project: EVO. In the game, the player floats down a river and negotiates a number of simultaneous tasks, which include navigating through ice floes and responding to various stimuli from the shore. Its developers, Akili Interactive Labs in Boston, announced in January that they had raised $30.5 million dollars in funding. The company’s next goal for the game is a bold one: approval from the Food and Drug Administration as the first digital game to be used in a number of medical applications.

Akili’s CEO, Eddie Martucci, holds a Ph.D. from Yale in molecular biophysics and biochemistry. He says that his company is being careful not to let its product claims outpace the science it conducts. And the science has been promising. A preliminary trial testing Project: EVO with 80 children, half of whom had attention deficit hyperactivity disorder, found that using the game led to improved attention in the group—results that were presented at the American Academy of Child & Adolescent Psychiatry’s annual meeting last October. Akili has also partnered with pharmaceutical giant Pfizer in a large clinical trial to see whether the game can detect early signs of Alzheimer’s disease. Other studies are looking into how the game might be useful for treating autism, depression and traumatic brain injuries.

Not everyone is optimistic that Akili will succeed. Randall Engle and his lab at the Georgia Institute of Technology have been studying this field, and one member of his team recently published a meta-analysis that looks critically at research into brain games. They have also and tried and failed to replicate a number of positive results from the field, though they have not yet attempted to replicate Gazzaley’s studies. Engle’s work was used as a basis for the FTC’s case against Lumosity, and two of his studies were cited in the Stanford letter.

“I turned 69 in December,” says Engle. “I’d love to believe that there is some video game that I could use that would delay the inevitable consequences of getting older. But we ought to be really skeptical.”

But Martucci says that Akili has committed to the scientific rigor needed to change minds in the research community, such as Engle’s, and looks forward to the rigor required for FDA approval. That includes running larger clinical trials to see whether Project: EVO can detect Alzheimer’s or improve symptoms of ADHD. Some of those are already underway, says Martucci, with the goal of winning FDA approval by 2018.

Time, as the Stanford letter laid out, is a precious commodity, especially for the elderly. If brain games can be a way to bring back critical brain power, then they are time well spent. If not, they remain what they have always been: a pleasant distraction to be taken in moderation.