Many studies have identified an association between cognitive activity and cognitive function. In other words, people who engage in mentally stimulating activities as they age also tend to maintain their cognitive ability longer. The nature of the relationship between activity and ability, however, remains unclear. Does mental stimulation actually make the brain stronger, or are people with higher cognitive functioning more likely to seek out mental stimulation? A recent study conducted by Rush University Medical Center in Chicago supports the hypothesis that cognitive activity may actually lead to better cognitive function.
The study is based on longitudinal data on cognitive function and activity among 1,076 participants in the Rush Memory and Aging Project, a study of chronic medical conditions among older adults. The participants were recruited from a variety of service agencies around the Chicago area, and took part in annual cognitive assessments. These assessments included a variety of established tests of different cognitive functions, including different types of memory and perception speed. The mean number of years in the study was 4.9, leading to a mean number of just under six evaluations (including the baseline evaluation) per participant.
To be included in this particular analysis, participants had to be without dementia and 65 years of age or better at the beginning of the study, and to take part in at least one annual follow-up. The mean age of participants was 80.4 years at the beginning of the study, with a mean of 14.5 years of education. Compared to the general population, participants were more likely to be white and non-Hispanic. In addition to the cognitive assessments, at each annual follow-up participants also reported on their involvement in seven different types of cognitively stimulating activity within the past year.
The researchers used what is called a cross-lagged panel model of analysis. Simply put, this is a method for analyzing the relationship between potentially reciprocal (as in, having a causal affect on one another) variables at multiple points in time. In this instance, this cross-lagged method enabled researchers to examine whether a higher level of cognitive activity in a given year was predictive of better cognitive function a year later, or vice versa.
Within this sample, a higher level of cognitive activity predicted a higher level of cognitive function in the following year. Cognitive function was not predictive of cognitive activity in the following year, with the exception of working memory, one of the three types of memory ability tested in the annual assessments. (Perceptual speed also came close to having a statistically significant affect on subsequent cognitive activity.) This study supports the hypothesis that cognitive engagement helps maintain cognitive function as we age. It does appear that some aspects of cognitive function, such as working memory and possibly perceptual speed, may be needed to support cognitive engagement.
The authors offer a few caveats, most notably that participants were selected and not representative of the general older adult population, and that cognitive activity was based on participant self-report of particular forms of cognitive activity. However, this study had several strengths, including a greater number of participants and a greater number of cognitive evaluations. This study is further support for mental stimulation as a strategy for healthy aging.