The April 20 edition of the online publication of NATURE published a study showing that in more than 11,000 healthy adults between 18 and 50 years of age brain training exercises were of no benefit. The group did the exercises three times a week for 6 weeks. At the end of the study the ones trained actually showed less improvement in cognitive function than control patients.
"A couple of years ago, I reviewed the literature on brain training and was surprised to find that, despite the fact that many millions of people are now involved in these types of activities, there is very little solid peer-reviewed scientific evidence out there to show that it actually works," lead author Adrian M. Owen, MD, from the Medical Research Council, Cognition and Brain Sciences Unit, Cambridge, United Kingdom, told reporters at a telephone press briefing. "This is a multi-million-pound industry, and given that so many people are involved, it is interesting that the scientific evidence was lacking."
Dr. Owen and his colleagues conducted an online study to investigate whether regular brain training leads to any improvement in cognitive function. Participants were randomly assigned to 1 of 3 groups. The first group trained in tasks that emphasized reasoning, planning, and problem-solving. The second group trained in a broader range of cognitive functions, which included tests of short-term memory, attention, visuospatial processing, and mathematics. To continuously challenge the participants' cognitive performance and maximize any benefits of training, the difficulty of the training increased as the participants improved.
The control group surfed the Internet to find answers to general knowledge questions.
At the end of 6 weeks, the participants were reassessed to see whether their cognitive functioning had improved. The researchers found that none of the brain training tasks transferred to other mental or cognitive abilities beyond what had been specifically practiced by each group. The control group also improved in their ability to answer obscure knowledge questions, although the effect size was small.
The study found that the training groups did get much better on the test that they actually practiced. In addition, participants got better the more they trained. However, even people who trained much more than average showed no generalization of training to untrained tasks — even those that were cognitively closely related.