2. The importance of ‘cognitive reserve’

Many definitions of cognitive reserve have been proposed, but this is the one preferred by Yaakov Stern, professor of Neurology at Columbia University. “Cognitive reserve is a property of the brain that allows it to continue functioning regardless of age-related changes and brain disease. It acts like a safety cushion: the bigger the reserve, the more damage the brain can accumulate before its effects are seen.

“Studies show, in general, that the higher the level of education, the greater the cognitive reserve,” explained Stern. This reduces the risk of serious cognitive deterioration and means that symptoms appear later even with the same level of neurodegeneration. “Once they appear in these people, however, they progress more quickly.”

Another related concept is brain maintenance, the relative absence of age-related changes in the brain, which depends on genetic, environmental and lifestyle factors. Although these are two independent concepts, they are also complementary and can have common influences. For Stern, it is key to standardize how we define and refer to these concepts because it “would be a great help for research and increase the chances of successful intervention.”

One way to quantify cognitive decline is using the “classic verbal episodic memory test,” which has patients repeat a list of words at different intervals of time. It is harder, though, to quantify cognitive reserve. To do so, University of Sydney Professor Michael Valenzuela has developed a procedure that looks at the rhythm and how the words are spoken instead of their content, in a sort of “vocal fingerprint”.

Although memory fails with cognitive decline, “not all types of memory suffer equally,” explained Lars Nyberg, professor of Neuroscience at Umeå University, Sweden. The most sensitive is episodic memory (related to personal experiences), but in some people it is preserved better than in others. Some of the modifiable factors that help preserve it are those mentioned previously, like physical activity, sleep, and nutrition. “There are three mechanisms involved,” noted Nyberg, and they have to do with “the neurons themselves (although there is some debate as to whether the hippocampus can generate new neurons throughout life), synapse integrity and vascular factors that feed the brain.”

Beyond the ‘traditional’ ways of caring for the brain, there may be more alternative options. One of them could be video games, but not “your typical video games; ones designed specifically for this purpose,” explained Joaquín A. Anguera, professor at the University of California, San Francisco. According to this researcher, video games can be a resource to boost cognitive control and be used with specific populations, like to help improve attention in children with attention-deficit and hyperactivity disorder.

Another way could be through meditation. The hypothesis presented by Gaël Chételat, director of research at Inserm in France, is that “it can improve cognition in the elderly and even help reduce the risk of developing Alzheimer.” Her studies are looking into the effects of combining practices like mindfulness and compassion meditation, as they seem to act on different brain mechanisms.