Caffeine, mental exercise benefit brain

Mental exercises and a common stimulant found in food and beverages can benefit brain function, according to two recent studies.

Caffeine can enhance long-term memory, and the effects last up to 24 hours after it is consumed, found Michael Yassa, PhD, and colleagues at Johns Hopkins University, who have published their research in the journal Nature Neuroscience.

The researchers conducted a double-blind trial in which participants who did not regularly eat or drink products containing caffeine received either a placebo or a 200-mg caffeine tablet five minutes after studying a series of images. The amount of caffeine in the tablet is the average U.S. adult daily intake and approximates the amount found in one strong cup or two small cups of coffee, three cups of brewed black tea or five 12-ounce servings of cola.

Saliva samples were taken from the participants before they ingested caffeine, and one, three and 24 hours afterward, to check for increased caffeine levels. The next day, both groups were tested on their ability to recognize images from a study session on the previous day. In the test, some of the visuals were identical to ones used the prior day, some were new and some were similar but not identical to the items previously viewed.

More participants in the caffeine group were able to correctly identify the new images as “similar” to previously viewed images versus erroneously citing them as the same, according to researchers. The brain’s ability to recognize the difference between two similar but not identical items reflects a deeper level of memory retention, they add. (Article continues below.)

“Using these items requires the brain to make a more difficult discrimination—what we call pattern separation, which seems to be the process that is enhanced by caffeine in our case,” says Yassa, the senior author of the paper and an assistant professor of psychological and brain sciences in the Krieger School of Arts and Sciences at Johns Hopkins.

Researchers now will try to determine exactly how caffeine affects the brain in this way, Yassa says. “We also know that caffeine is associated with healthy longevity and may have some protective effects from cognitive decline like Alzheimer’s disease,” he adds. “These are certainly important questions for the future.”

The research was supported by grants from the National Institute on Aging and the National Science Foundation.

COGNITIVE TRAINING

In other news, 10 hour-long sessions of exercises can improve the brain’s ability to reason and process information in a timely way, and some of the effects can last for 10 years after the training, say researchers publishing the results of their clinical trials in the January issue of the Journal of the American Geriatrics Society.

“Showing that training gains are maintained for up to 10 years is a remarkable result, because it suggests that a fairly modest intervention in practicing mental skills can have long-term effects on older adults’ cognition and daily function beyond what we might reasonably expect,” says George Rebok, PhD, a professor in the Department of Mental Health and the Center on Aging and Health at the Johns Hopkins Bloomberg School of Public Health and one of the study’s six investigators.

The report, from the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study, assessed 2,800 volunteers (average age at the start of the study: 74 years) who were divided into three training groups—reasoning, speed of processing and memory—and a control group. The members of the training groups participated in 10 60- to 70-minute sessions over five to six weeks, with some participants randomly selected for later “booster” sessions. The study measured effects for each specific cognitive ability trained immediately following the sessions and at one, two, three, five and 10 years after the training.

Members of all groups showed declines in the three cognitive categories after the trial ended, but those who had received training in reasoning and speed of mental processing experienced less decline than those who had not been trained.

After 10 years, 73.6 percent of reasoning-trained participants were still performing reasoning tasks above their baseline level before the trial compared with 61.7 percent of control participants, who received no training and were only benefiting from practice on the test. This same pattern was seen in speed training: 70.7 percent of speed-trained participants were performing at or above their baseline level compared with 48.8 percent of controls. The results for memory-trained participants were not significant.

The investigators also assessed whether the training affected participants’ abilities to undertake complex activities of daily living (ADLs), using composite measures and asking the participants themselves about their ability to handle such tasks. Ten years after initial training, members of all three training groups reported less difficulty in performing ADLs than members of the control group. A significant percent of participants in all trained groups (at least 60 percent) continued to report less difficulty performing ADLs compared with non-trained participants (49 percent). After 10 years, 60 percent to 70 percent of participants said they were as well or better off than when they started.

The study was supported by the National Institute on Aging and the National Institute of Nursing Research, both components of the National Institutes of Health.

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