“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: 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 math; and a control group (2,738 subjects), which answered various questions using the Internet. The groups were matched in size initially, but more of the control group members dropped out before the final assessment. Participants were recruited from viewers of a British science TV show.
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 (available 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 (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 (Nature 2010 April 20 [doi:10.1038/nature09042]).
“Six weeks of regular computerized brain training confers no greater benefit than simply answering general knowledge questions using the Internet,” the study authors concluded.
Disclosures: The authors reported having no conflicts.
My Take
A Credible Study on a Complex Question
The notion of exercising the mind to reduce its deterioration is popular in the world of Alzheimer's disease: Do more 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 they conceptualize it in this way or not. 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 ultimately vanishes as any skill becomes automatic (Proc. Natl. Acad. Sci. USA 1998;95:853-60).
Cognitive tasks, in contrast to sensorimotor 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.
The background of the question is complex, but given the effort required to achieve even a “simple” practice effect, studies such as that of Adrian M. 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., is a professor of neurology at the Mayo Clinic Arizona, Scottsdale. He has no financial conflicts of interest related to this subject.
