Jibes about Joe Biden’s age shine light on issues facing older politicians

It should have been a good day for Joe Biden. After all, no charges are to be filed against the US president after an inquiry into his mishandling of classified files. But the official report from Robert Hur, the special counsel at the Department of Justice, was devastating nonetheless.

Hur’s description of Biden, 81, as an “elderly man with a poor memory” who had “diminished faculties in advancing age” provoked an outraged defence from the White House.

The incident has shone fresh light on the sensitive issue of older politicians and the risks that come with leaders who are long past what most countries regard as the standard age of retirement. The brutal fact is that the brain is not spared the physical decline that comes with old age, though the degree of decline varies enormously.

Brain scans over the human lifespan reveal a rise and fall in brain size. From adulthood onwards, the brain starts to shrink as people lose grey and white matter. The grey matter is largely brain cell bodies, while white matter is the bundles of nerve fibres that connect neurons into functional brain circuits.

In healthy ageing, the shrinkage is gradual, though it tends to speed up when people reach their 70s or 80s. In dementia, the decline becomes rapid.

Even in healthy ageing, the shrinkage has consequences. “If you have less brain matter, that’s going to affect cognition, because you are losing neurons and the connections between them. The network is not going to be in as good a shape as we age,” says Prof Tara Spires-Jones at the UK Dementia Research Institute at the University of Edinburgh.

“You don’t lose a huge number of neurons, but you do lose connections between them in various regions of the brain, and that probably plays a big part