Brain exercise programs are rapidly expanding in popularity, already generating more than $80 million in sales a year. Marketing has targeted the anxieties of elderly populations that fear mental decline and dementia. A new study by Dr. Kathryn Papp, published in the most recent edition of Alzheimer’s and Dementia, examines the claims that these products can stave off the cognitive problems of old age.

Dr. Papp surveyed all previous studies on the efficacy of brain exercise programs and found frequent methodological weaknesses. Many studies did not compare the intervention group with a similarly active control group, follow-up to check if any effects were lasting, or measure more general cognitive ability. These flaws can easily lead to deceptive results. For example, lack of an active control group obscures the fact that physical exercise has a positive effect on cognition that may far outweigh any benefit from brain exercise programs. Similarly, the lack of follow-up or general cognitive evaluation may conceal the fact that the gains from brain exercise programs are transient or narrowly task-specific. It is possible that repetitive games cannot trigger the neural growth usually spurred by novelty, and that narrowly circumscribed games do not preserve the whole brain but only the specific parts engaged in playing that game.

Even when Dr. Papp included the flawed, and thus probably biased towards finding efficacy, studies, she found only a slight rise in cognitive scores and no significant delay of Alzheimer’s onset or progression. This meta-study highlights a worrying deficiency in evidentiary support for the efficacy of brain exercise programs. We do, however, have strong evidence for the benefit of three things that should not be neglected for unproven brain exercise programs: nutritious meals, exercise, and social stimulation. Neglect is a real danger because playing a computer game by yourself can preclude exercise, socializing, and even nutritious eating (if the game is engrossing enough to induce meal skipping, or fast-food eating instead of cooking). Dr. Papp’s research does not rule out the possibility that brain exercise programs work, but it does suggest that they should not be relied on until credible evidence is produced by well-designed studies.