Do brain-training games help prevent cognitive decline?

Cognitive training offers modest benefits to people who already have memory problems, but these studies say nothing about healthy individuals who want to prevent decline. In Alzheimer's disease and mild cognitive impairment (MCI), meta-analyses found a medium-sized positive effect on general thinking ability, with a slightly larger effect in people with Alzheimer's than in those with MCI. That improvement remained visible at follow-up.

Cognitive training works most clearly in mild dementia. The more severe the dementia, the less certain the benefit. Cognitive rehabilitation, which teaches people to cope with everyday limitations, also reduces the burden on caregivers. These are meaningful practical gains, even if the cognitive effects are not spectacularly large.

Whether brain stimulation adds anything to cognitive training remains unclear. A well-designed randomised study found no advantage of the combination on the primary outcome measure. A weak positive signal on working memory disappeared as soon as the most rigorous method of analysis was applied. This puts a brake on overly optimistic claims about 'enhanced' training protocols.

In progressive multiple sclerosis (MS), a large international study across six countries found that cognitive rehabilitation produced no measurable gain. That is a clear negative result. In Parkinson's disease there are preliminary indications, but it has not yet been demonstrated that training slows the transition to dementia.