27 Dec 2006

If exercising the body can protect against diabetes and heart disease, then perhaps exercising the brain may protect against cognitive decline. That’s the premise of ACTIVE (Advanced Cognitive Trial for Independent and Vital Elderly), the first multicenter, randomized controlled trial to determine if cognitive training helps older adults to maintain their capacity to handle a variety of day-to-day tasks. Results of the five-year follow-up to ACTIVE, reported in the December 20 Journal of the American Medical Association, are a bit of a mixed bag. Writing for the ACTIVE study group, first author Sherry Willis, Pennsylvania State University, State College, and colleagues report that trial recruits did perform better in the specific domains trained, but that this does not necessarily transfer to a positive effect on daily function.

Maintaining independence is of vital importance to older adults, who are forced to give up that precious way of life if they become cognitively impaired, as in the case of Alzheimer disease and other forms of dementia. Recent studies hint that exercising the brain may stave off cognitive decline (see ARF related news story). To test that idea, ACTIVE recruited older adults who lived independently and had good functional and cognitive ability (see Jobe et al., 2001 for more on study design). Of the 5,000 volunteers recruited, 2,832 were accepted and randomized into four groups. One served as control and the others were trained in one of three domains: reason, memory, and speed of processing. Initial training consisted of ten 60-75-minute sessions, while “booster” training, given at 11 and 35 months later, consisted of four 75-minute sessions. During training the volunteers were taught strategies for finding patterns in letter or word series (reason training), mnemonic devices for remembering verbal material (memory training), and visual search and attention skills (speed of processing). Two basic premises of the study were that the training would affect and improve the targeted cognitive ability and that the improvement would have a positive effect on everyday function.

The first premise was upheld. Volunteers showed an immediate improvement in the cognitive domain trained, and this improvement was also apparent at 5-year follow-up. But while all three test groups had better self-reported scores on instrumental activities of daily living (IADL), statistical significance was only reached in the group trained in reasoning. The results suggest that while cognitive training can prevent cognitive decline in specific domains, further work is needed to determine what kind of training, if any, can prevent the deterioration in activities of daily living that leads to loss of independence.

One particularly interesting approach may be to train several domains simultaneously. As Sally Shumaker, Wake Forest University Health Services, Winston-Salem, North Carolina, and colleagues write in a JAMA editorial, “The choice of cognitive domain-specific interventions in ACTIVE may have limited the potential for detecting an effect of intervention in functional status.” More recent approaches aim toward more general, cross-domain training that might have more powerful effects, they add.

In addition, Shumaker and colleagues note “The ACTIVE study also underscores the complexities and challenges inherent in this type of research.” As Willis and colleagues point out, for example, it was not possible to “blind” participants to their treatment. Therefore, the self-reported IADL scores may reflect a certain degree of expectation among those who received the training. Performance-based IADL scores, for example, revealed no general effect of training, though those who received speed of processing training did perform significantly better in functional speed of processing tests at 5-year follow-up if they had also received the booster training. Willis and colleagues suggest that for self-reported IADLs, the design of some kind of placebo control group will be an important direction to take in this type of research.—Tom Fagan