It must have been a good day for Joe Biden. After all, no charges will be brought against the US president after an investigation into his mishandling of classified files. But the official report from Robert Hur, the special counsel at the Department of Justice, was nonetheless devastating.
Hur’s description of Biden, 81, as an “elderly man with a failing memory” who had “diminished abilities in advanced age” drew an outraged defense from the White House.
The incident has shed fresh light on the sensitive issue of older politicians and the risks associated with leaders who are long past what most countries consider the standard age of retirement. The brutal fact is that the brain is not spared the physical deterioration that comes with age, although the degree of deterioration varies enormously.
Brain scans over the human lifespan show a rise and fall in brain size. From adulthood, the brain begins to shrink as people lose gray and white matter. The gray matter is mainly brain cell bodies, while white matter is the bundles of nerve fibers that connect neurons into functional brain circuits.
In healthy aging, the shrinkage is gradual, although it tends to accelerate as people reach their 70s or 80s. In dementia the decline is rapid.
Even in healthy aging, the shrinkage has consequences. “If you have less brain matter, it’s going to affect cognition because you lose neurons and the connections between them. The network is not going to be in such good shape as we get older,” says Prof Tara Spiers-Jones at the UK Dementia Research Institute at the University of Edinburgh.
“You don’t lose a large number of neurons, but you do lose connections between them in various regions of the brain, and that probably plays a big role in why we don’t think as well.”
However, there is no large-scale decline in mental ability. Memory and cognition tests paint a more nuanced picture. People vary enormously, but common knowledge tends to hold up. Vocabulary often improves after retirement age.
However, many other skills worsen. Working memory – tasks such as remembering phone numbers – tends to decline. People find it harder to learn new information. Old brains simply work more slowly.
The effects may be strongest when people are trying to recall information. The knowledge is buried somewhere in the brain, but retrieval can slow down in old age. This is sometimes seen when an older team takes on a younger team on University Challenge, says Dennis Chan, a consultant neurologist and professor at University College London’s Institute of Cognitive Neuroscience. “You can hear the older people moaning. They know the answer, but they can’t remember it,” he says.
Hur makes specific, unflattering mention of Biden’s memory in his 345-page report, noting that it would be difficult to convince jurors that Biden knew he was wrong, and speculating that his lawyers are likely to “limit his recall ” will emphasize.
Another skill that declines with age is attention; our ability to focus on a particular thought or task. Ever found yourself in the kitchen without remembering why you went there? Or do you forget where you put your car keys? Or put the milk back in the granary rather than in the fridge? Such declines tend to become more common in older age, although there may be reasons other than a faltering brain.
“It can happen more often when you’re older because you have more things to think about,” says Chan. “It could be aging, but there are other factors, such as having a lot of things on your mind, stress or lack of sleep. It’s not necessarily pathological.”
While some mental decline is on the horizon for most, research suggests a number of actions people can take to ensure their brains stay healthy into old age. Doctors advise that what is good for the heart is good for the brain. This means no smoking or excessive drinking, a healthy diet and regular physical exercise. It helps keep the cardiovascular system healthy, which is essential for a healthy brain.
But stimulation is also essential. Chan advises people to challenge themselves mentally and encourages frequent socialization, because social interactions are so mentally demanding. He emphasizes the importance of new activities because they force the brain to make new connections.
“Doing something out of the ordinary is much more challenging for the brain,” says Chan. “And the more we engage our brain, the more we encourage it to grow new synapses, new connections, and that will help everything.”
