Signs of cognitive decline, particularly related to Alzheimer’s disease, may be detectable through the way individuals speak, according to a recent study from the University of Toronto. The research suggests that the pace of everyday speech could serve as a more reliable indicator of cognitive health than previously recognized factors, such as the common difficulty of finding words, known as lethologica or the “tip of the tongue” phenomenon.
As people age, their ability to retrieve words can diminish, particularly after the age of 60. To investigate this, researchers analyzed the speech patterns of 125 healthy adults aged between 18 and 90. Participants were tasked with describing a scene in detail, after which they were shown images of common objects while listening to audio that could either confirm or confuse their responses. For example, if a participant saw a picture of a broom, the audio might say “groom,” which aids in word recall through rhyme, or present a related but incorrect term like “mop,” which could momentarily disrupt their thought process.
The study revealed a significant correlation between the speed of natural speech during the first task and the rapidity of responses in the second task. This finding aligns with the processing speed theory, which posits that a general slowdown in cognitive processing contributes to cognitive decline, rather than a specific decrease in memory function.
According to the team led by psychologist Hsi T. Wei from the University of Toronto, “Older adults are significantly slower than younger adults in completing various cognitive tasks, including word production tasks such as picture naming, answering questions, or reading written words.” The research also highlighted that older adults tend to exhibit more dysfluencies, such as unfilled and filled pauses (e.g., “uh” and “um”), resulting in a slower overall speech rate.
In a separate analysis published in The Conversation in 2024, dementia researcher Claire Lancaster noted the importance of these findings, stating, “The study from Toronto has opened exciting doors… showing that it’s not just what we say but how fast we say it that can reveal cognitive changes.” This perspective is particularly relevant as advancements in artificial intelligence have enabled algorithms to predict Alzheimer’s diagnoses with an accuracy of 78.5 percent based solely on speech patterns.
Additional studies have reinforced these findings, indicating that patients exhibiting signs of amyloid plaque—an indicator of Alzheimer’s—are 1.2 times more likely to experience speech-related issues. Furthermore, research conducted at Stanford University in 2024 found that longer pauses and slower speech rates correlated with increased levels of tangled tau proteins, another defining feature of Alzheimer’s disease.
The implications of these studies are significant. They suggest that changes in speech could reflect the development of Alzheimer’s pathology even before overt cognitive impairment occurs. As researchers continue to explore the nuances of human speech, they are making strides toward understanding what our communication reveals about our cognitive health.
The findings from the University of Toronto’s 2023 study were published in the journal Aging, Neuropsychology, and Cognition. As scientists delve deeper into the relationship between speech and cognitive decline, the potential for early diagnosis and intervention moves closer to becoming a reality.
