Language Changes: Normal Ageing Or A Dementia Red Flag?

Comment provided by cognitive neuroscientist Dr Adolfo M García, Director of the Cognitive Neuroscience Centre, Atlantic Fellow at the Global Brain Health Institute, and Associate Researcher at Universidad de Santiago de Chile. He is also the creator of the speech testing app TELL.

Sometimes, dementia changes how people speak. Because it can affect the part of the brain responsible for language, it may mean those with the condition struggle to finish a sentence, replace an intended word with another one, or jumble up their words.

But writing in Nature recently, cognitive neuroscientist Dr Adolfo M García said that while some language changes are normal in “healthy” ageing, others might signal dementia risk before it is clinically recognised.

Speaking to HuffPost UK, he said that Alzheimer-specific changes “may begin several years before core dementia symptoms appear.”

Noticing changes to your speech as you age doesn’t necessarily mean something is wrong.

“Compared with younger adults, healthy older adults may speak more slowly, take longer to find the right word, or lose their train of thought occasionally. Conversations can become a little less clear or detailed,” Dr García told us.

In fact, among those ageing healthily, many can expect improvements in some parts of their language.

“Their overall knowledge of words often grows, thanks to a lifetime of experience, so they may actually have a richer vocabulary than younger people.”

That idea is echoed in a theory called Heap’s law, “which posits that crystallised intelligence (knowledge accumulation) remains stable or improves in older adults”.

But, the neurologist added, “Dementia looks different. The key issue is not just slowing down ― it is losing words and meanings. People may struggle to name everyday objects, use vaguer or incorrect words, or mix up meanings (for example, calling a ‘chair’ a ‘table’). Their speech can become less coherent and harder to follow.

He added that while “normal ageing” can lead to “delayed processing with preserved or increased knowledge,” dementia “affects what we actually know and can express.

“Vocabulary knowledge is the most clearly distinct domain between healthy ageing and Alzheimer’s, as it increases in the former and is markedly reduced in the latter.”

At the moment, there is no single test for dementia. And many cases are diagnosed years after the first symptoms begin (an average of 3.5 years, per one study).

Dr García told us that “changes in word processing and other language domains may begin several years before core dementia symptoms appear. This is a vital discovery, as the chances of effective intervention increase drastically when people at risk are detected early on (that is, when neurodegeneration has begun but clinical manifestations are not yet visible).”

He hopes that advanced language analysis software can raise those key flags sooner.

“The evidence keeps growing, research funds multiply, and user-friendly apps are becoming more available (like our very own TELL app). The core challenge, moving forward, is how to accelerate widespread adoption from clinicians and other stakeholders, so that these technologies can be globally harnessed for equitable dementia screening, diagnosis, prognosis, and monitoring.”