Doing This Thing While Talking Is a Sign of Oncoming Dementia, Scientists Find

Forgetting words is a common experience — but when your speech starts slowing, it could signal something worse.

As dementia researchers explain in The Conversation, a new study had found that slowed-down speech may be a greater early indicator of dementia than "lethologica," the medical term for forgetting words.

Conducted by researchers out of the University of Toronto, the new study showed pictures over video chat to 125 healthy adults between the wide age range of 18 and 90 and then asked them to describe the scenes they'd just viewed. Those descriptions were then analyzed using artificial intelligence to pinpoint details such as speech speed, how long participants paused between words, and how many different words they used.

Also over video chat, those same 125 study participants completed questionnaires that measured "executive functioning" tasks, such as their ability to concentrate, how fast they thought, and how well they could plan and carry out tasks. As it turned out, there seemed to be a correlation between executive functioning and the speed of their speech — especially in older participants.

In particular, the two University of Sussex dementia researchers who wrote the editorial, neither of whom was involved in the Toronto study itself, said that although the experiment's picture-describing tasks were compelling, the findings based on that task might not reflect real-world language processing.

Known as a "picture-word inference task," the experiment showed photos of objects like a broom and then played audio either of an unrelated word like "mop" or a word that sounds similar, such as "groom."

"Interestingly, the study found that the natural speech speed of older adults was related to their quickness in naming pictures," Claire Lancaster and Alice Stanton, the Sussex researchers, wrote. "This highlights that a general slowdown in processing might underlie broader cognitive and linguistic changes with age, rather than a specific challenge in memory retrieval for words."

In everyday life, one isn't likely to experience that sort of test in everyday life. The Toronto researchers could, as the Sussex experts suggested, have chosen other tasks such as verbal fluency tests that measure whether people are able to retrieve words that are on the "tip of their tongue."

"Personal reports of the 'feeling' of struggling to retrieve words could offer valuable insights complementing the [behavioral] data," the unrelated researchers wrote, "potentially leading to more powerful tools for quantifying and detecting early cognitive decline."

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