Early indicators of cognitive decline, particularly related to Alzheimer’s disease, may be discernible through speech patterns, according to recent research conducted by scientists at the University of Toronto. A study published in 2023 suggests that the pace at which individuals speak could hold more significance for diagnosing cognitive decline than previously thought, particularly the challenges associated with word retrieval.
The research focused on the phenomenon known as lethologica, often referred to as the “tip of the tongue” experience, which can affect both younger and older individuals. However, for those over the age of 60, the struggle to retrieve specific words may become more pronounced. To investigate this trend, researchers enlisted 125 healthy adults between the ages of 18 and 90 to describe a scene in detail, aiming to identify key speech traits that may indicate cognitive changes.
Participants were shown images of everyday objects while listening to audio designed to confirm or confuse their responses. For example, the sound of the word “groom” might accompany a picture of a broom, prompting recall through rhyme; conversely, a related word like “mop” could momentarily mislead the participants. The findings revealed that those who spoke at a faster natural pace during the first task were able to generate answers more quickly in the second task.
This aligns with the processing speed theory, which posits that a general decline in cognitive processing speed is central to cognitive decline, rather than issues specifically tied to memory. Dr. Hsi T. Wei, leading the research team, noted, “It is clear that 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.”
Speech Patterns and Alzheimer’s Risk
In a subsequent commentary for The Conversation, dementia researcher Claire Lancaster highlighted the significance of the study, stating that it “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 reinforced by emerging technologies, with some artificial intelligence algorithms successfully predicting an Alzheimer’s diagnosis with an accuracy of 78.5 percent based solely on speech patterns.
Further research has demonstrated a connection between speech-related difficulties and the presence of amyloid plaques in the brain, a hallmark of Alzheimer’s disease. Individuals exhibiting more signs of these plaques are 1.2 times more likely to experience speech-related issues. Additionally, a 2024 study from Stanford University found that longer pauses and slower speech rates correlate with higher levels of tangled tau proteins, another characteristic associated with Alzheimer’s.
“This suggests that speech changes reflect the development of Alzheimer’s disease pathology even in the absence of overt cognitive impairment,” the Stanford researchers concluded.
As scientists continue to explore the complexities of human speech, the groundwork is being laid for a deeper understanding of how our words might signal changes in cognitive health. The 2023 study published in Aging, Neuropsychology, and Cognition marks an important step towards uncovering the nuances of speech as a potential diagnostic tool for cognitive decline, emphasizing the importance of both the content of our speech and the manner in which we communicate.
