You know the saying “you can’t teach old dogs new tricks”? Well, it turns out that that is not even true for dogs, much less humans. We now know that healthy people can gain new skills and knowledge in older life; and vocabulary even increases until we are about 60 years of age, after which it remains stable, or may slightly decrease.

The bad news is that the brain ages, just like the body. It begins to shrink in our 30s and 40 and loses 5% of its volume each decade until around 70 years. Certain areas of the brain responsible for cognitive functions and memory may shrink more than others. The metabolism and biochemistry of brain cells and the connections in the brain may also change.

It is not surprising then, that normal ageing of the brain is often associated with changes in cognitive function, such as slower processing speeds, difficulties in multi-tasking and less-than-perfect recall. While this can impact on our ability to do complex tasks as we age, for most people retention of knowledge, routine skills and memory are not affected by age.

Normal ageing vs dementia

I can’t remember when the terms “thingummybob” and “whathisname” became household words, but my mother must have been somewhere in her early 60s. In those days it was considered normal for older people to forget names and function less efficiently. That, after all, is what young people were there for. (And also, to thread needles.) We did, however, speak in hushed tones about people we knew who had “gone senile” in their old age. But it was never expected to happen to our parents (or us).

Nowadays dementia is a buzzword and everyone I know—young and old—is terrified that they will get it. Or indeed that they are already showing signs.

Dementia is a generic term that incorporates a range of cognitive diseases. It is defined as the loss of cognitive functioning—thinking, remembering, and reasoning—to the extent that it interferes with a person's daily life and activities. It is important to know that there is not a slippery slope from mild cognitive impairment to dementia. Even less so, is it a genetic certainty. Though your older relatives may have suffered from dementia, it is not inevitable that you will get it, even if you have the gene that predisposes you to it. In fact, most geriatricians believe that up to 40% of dementia is preventable.

In this post we focus on the positive aspects of brain health and the next will go into more detail about dementia.

Cognitive reserve and brain maintenance
Recent research has identified a category of people dubbed the “cognitive superagers” who perform better on memory tests and word recall than average for their age. Physically, their brains defy expected wear and tear and are thicker and richer in cells in important areas. Researchers are exploring several hypotheses to explain this including being born with larger, stronger brains; and abilities to adapt to or defend against ageing.

There’s nothing you can do about what you are born with, but research into the adaptability of the ageing brain gives us a lot to think about. Two theories here revolve around the concept of “cognitive reserve” and “brain maintenance”. Cognitive reserve is the idea that some brains are better able to cope with the assaults of aging and disease. Brain maintenance is the process of preserving brain structure and function, potentially delaying age-related changes.

As ageing researcher Dr Claudia Kawas explains, “You can super-age by not getting Alzheimer’s pathology, or you can super-age by getting it and somehow managing to not get sick with it.”

These ideas were initially developed to explain the lack of correlation between physical changes in the brain, as seen on scans, and outward signs of those changes.

A key study here (“the nun study”) involved a group of elderly Catholic sisters who agreed to participate in a scientific investigation of the relationship between normal cognition and physical evidence of brain lesions typical of Alzheimer’s disease (AD). This included detailed assessments of their cognitive performance and examination of their brains after death. Researchers found a significant number of the participants’ brains had signs of AD, despite the fact that they had performed well on the cognitive assessments. What distinguished the well from the ill was evidence from autobiographies written before the novice nuns joined the religious order. Those who used more descriptive language, ideas and complex grammar were likely to be better protected from cognitive decline, while those whose writing was plainer and less expressive were more likely to experience dementia.

Other studies have made similar findings, leading to the conclusion that some people’s brains may be more resilient to aging and neurodegeneration than others. In addition to educational level (and good imagination) several other modifiable health factors have been proposed. This leads to the inevitable conclusion that there may be things we can do at different stages of the life course to strengthen brain health and cognitive reserve. There is a huge ongoing research agenda here, though this may be curtailed by the slash-and-burn approach to research spending by the current US administration.

Do-it-yourself brain health
Current research has already identified a range of interventions to improve brain health and potentially ward off dementia. Here we look at six simple ways to preserve your brain.