Major Finding: Improvements seen in “brain training” tasks translated poorly to performance on benchmarking tests that used similar cognitive functions (effect sizes, 0.01–0.22).
Data Source: A 6-week trial of brain training exercises in 11,430 participants
Disclosures: The authors reported having no financial conflicts of interest.
“Brain training” does not improve general cognitive function, according to a 6-week trial of more than 11,000 participants.
The study results “provide no evidence for any generalized improvements in cognitive function following brain training in a large sample of healthy adults,” Adrian M. Owen and his colleagues reported.
The participants were divided into three groups: the experimental group 1 (4,678 subjects), which did six tasks emphasizing reasoning, planning, and problem solving; experimental group 2 (4,014 subjects), which practiced six tasks focusing on short-term memory, attention, visuospatial processing, and mathematics; and a control group (2,738 subjects), which answered various research questions using the Internet. The groups were matched in size initially, but more of the control group members dropped out before the final assessment. The participants were recruited from among viewers of a British science television show (Nature 2010 Apr. 20 [doi:10.1038/nature09042
The tasks given to group 2 were considered to be most like those of commercially available “brain training” programs, said Mr. Owen of the Medical Research Council Cognition and Brain Sciences Unit, Cambridge, England, and his colleagues.
The participants were assessed before and after the intervention using benchmarking tests that measured reasoning, verbal short-term memory, spatial working memory, and paired-associates learning. These validated cognitive assessment tools (at www.cambridgebrainsciences.com
Participants completed an average of 24 training sessions over the 6-week period (range, 1–188). The tasks were performed for a minimum of 10 minutes a day, three times a week. All three groups improved on the tasks they had been assigned to practice during the trial (effect sizes: group 1, 0.73–1.63; group 2, 0.72–0.97; controls, 0.33). However, postintervention improvements on the benchmarking tests were much smaller (effect sizes, 0.01–0.22 for all groups). The control group improved slightly more than the experimental groups on two measures.
The groups were similar in age (average, 39–40 years) and gender (each group had 4–5 times as many female participants). No relationship was seen between number of training sessions performed or age of participants and postintervention benchmarking test scores. The scores on two tests reflected small gender differences.
Although participants improved at their assigned tasks, “training-related improvements may not even generalize to other tasks that use similar cognitive functions,” the researchers said.
My Take
Credible Study Addresses a Complex Question
The notion of exercising the mind to reduce its deterioration is popular in the world of Alzheimer's disease: Do crossword puzzles and you will slow the progression of dementia. But is it true? Epidemiological studies have shown mixed results, possibly reflecting presymptomatic-stage disease, confounding medical issues, and medications influencing outcomes.
Most people “exercise” their brain during their daily activities whether or not they conceptualize it in this way. The term “brain training” implies some kind of special activity that the term “practice” lacks, but acquiring any new skill requires enhanced attention, and with increasing task familiarity comes greater automaticity and increasing dexterity. Functional brain imaging studies show activation of prefrontal cortices during the early attentional practice stage that diminishes and vanishes as any skill becomes automatic (Proc. Natl. Acad. Sci. USA 1998;95:853–60).
Cognitive tasks rely on the integration of multiple brain regions that are geographically distant and serve different functions. Because a related, nonidentical task might use this network, it is conceivable that related tasks may be performed with greater facility and dexterity.
Given the effort required to achieve even a “simple” practice effect, studies such as that of Mr. Owen and his colleagues that fail to show any major translational skill differences after a mere 6 weeks of “brain exercises” that sound far less grueling than the practice of professional musicians and athletes are certainly credible.
RICHARD J. CASELLI, M.D., medical editor of