Early indicators of cognitive decline, particularly related to Alzheimer’s disease, may be found in how individuals express themselves verbally. A study conducted by researchers at the University of Toronto emphasizes that the nuances of speech may play a more crucial role in predicting cognitive issues than previously realized.
The 2023 research suggests that the pace of speech could serve as a more significant marker of cognitive decline than the common experience of difficulty in word retrieval. Known as lethologica or the “tip of the tongue” phenomenon, this challenge affects both young and older adults. Yet, it appears to become increasingly prominent after the age of 60.
To investigate this, the researchers engaged 125 healthy adults aged between 18 and 90 in a speaking task where they were asked to describe an image in detail. Following this, participants viewed images of common objects accompanied by audio designed to assist or mislead their word recall. For example, when shown a picture of a broom, participants might hear the word “groom,” linking sounds to enhance memory. Conversely, hearing a related word like “mop” could disrupt their thought process temporarily.
The findings revealed a correlation: individuals with a faster natural speech rate in the initial task tended to provide quicker answers in the subsequent task. This supports the processing speed theory, which posits that a generalized slowdown in cognitive processing, rather than a specific decline in memory, is at the heart of cognitive issues.
The research team, led by psychologist Hsi T. Wei, highlighted that older adults often show significant delays compared to younger adults when completing cognitive tasks, including word production. They also noted an increase in speech dysfluencies—pauses marked by fillers like “uh” and “um”—and a generally slower speech rate among older participants.
In a commentary published in The Conversation in 2024, dementia researcher Claire Lancaster remarked on the implications of the Toronto 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.”
The potential for technology in this area is noteworthy. Recent advancements in artificial intelligence have reportedly achieved an accuracy rate of 78.5 percent in predicting Alzheimer’s diagnoses based solely on speech patterns. Additional studies indicate that individuals exhibiting more signs of amyloid plaques, a hallmark of Alzheimer’s, are 1.2 times more likely to experience speech-related difficulties.
In another study conducted by researchers at Stanford University in 2024, it was found that longer pauses and slower speech rates were connected to elevated levels of tangled tau proteins, another defining feature of Alzheimer’s disease.
The authors of this study concluded that changes in speech may reflect the progression of Alzheimer’s disease pathology, even when cognitive impairment is not yet evident. The findings indicate that researchers are making strides in understanding the intricate connections between speech patterns and cognitive health.
As the groundwork continues to develop, the potential for identifying early signs of cognitive decline through speech is becoming clearer. The 2023 study was published in the journal Aging, Neuropsychology, and Cognition, marking a significant step forward in this emerging field of research.
