It has happened to all of us: you are talking and suddenly you go blank. You know exactly what you want to say, but the word won’t come out. “Pass me the… this… that thing next to the gadget” or you directly say another word and think “why did I say that?” Nothing is happening in your brain, for now. What you are experiencing is called lethologica, and it is quite common in humans, although it gets worse with age.
For years it was thought that forgetting single words was one of the first signs of Alzheimer’s, but a recent study from the University of Toronto believes it has to do with the speed at which we speak.
What does your way of speaking say?
The researchers gathered 125 adults, between 18 and 90 years old. They asked them to describe out loud any scene, while recording everything they said. Then, using AI, they analyzed aspects such as speech speed, how much they paused between words, and how much variety there was in their vocabulary.
They also gave them tests of concentration, mental quickness, and planning. The result was that the slower someone spoke, the more noticeable the effects of aging were on their overall cognitive ability. That is, it was not only a matter of “oops, I lost the word,” but of slower mental processing in general.
And how did they measure if someone takes longer to find a word?
They used an experiment called picture-word interference task. Basically, it is showing photos of everyday objects (like a broom), while through the headphones a word is played that may be related (for example “mop,” which confuses the brain a bit) or sounds similar.
This type of test serves to separate two different mental processes: thinking the word and saying it out loud. And what they saw is that older people who spoke more slowly also took longer to name the images, even when they did not have obvious memory problems.
What does this have to do with Alzheimer’s?
Well, the people who took the test were not diagnosed with Alzheimer’s, they were healthy adults, but it is interesting how long before the clearer symptoms of the disease begin, changes are already detected in how the brain handles language.
So if someone starts speaking more slowly progressively and without apparent reason, it could be one of those silent signs.
Wouldn’t it be better to use another type of test?
Some experts think that describing an image may not be enough to detect those tip-of-the-tongue failures. That is why they propose combining it with the so-called verbal fluency tests: asking someone to say all the fruits or animals they can think of in one minute, or to list words that start with a specific letter.
What is missing
Although the Toronto study was very complete, some specialists believe it would have been interesting to also include how people feel when searching for words. That is, combining what the machine says with what the participant themselves says: if they notice they get stuck, if it frustrates them, if it happens more often than before…
The most important part of this study
The pace of speech matters more than we thought. It is not only what we say, but how we say it. Thanks to artificial intelligence tools such as natural language processing, we can analyze these things automatically and very accurately.
In fact, there are already investigations that have detected these language changes by analyzing the speeches of public figures like Ronald Reagan or Iris Murdoch, years before they were officially diagnosed with dementia. The difference is that those studies were retrospective. This one looks forward.
We speak more slowly. We pause more. We hesitate more when looking for a word. And sometimes we think these are normal things of aging. But this study says something else: that those small details may be the first clues of more serious cognitive decline. We must pay close attention to how speech changes