Scientists have identified that changes in speech patterns may serve as early indicators of cognitive decline, particularly relating to Alzheimer’s disease. A study conducted by researchers at the University of Toronto reveals that the speed of speech could be a more significant predictor of cognitive health than previously recognized factors such as word retrieval difficulties.
The research, published in the journal Aging, Neuropsychology, and Cognition in 2023, involved 125 healthy adults aged between 18 and 90. Participants were tasked with describing a scene in detail. Following this, they viewed images of everyday objects while listening to audio designed to either assist or confuse their recall. For example, when shown a picture of a broom, the audio might say “groom,” creating a rhyme to aid memory. Conversely, it could mention a related term like “mop,” which could mislead the participant momentarily.
The findings indicated that individuals with a faster natural speech rate during the initial task tended to respond more quickly in the second task. This aligns with the processing speed theory, which posits that a general slowdown in cognitive processing is at the core of cognitive decline rather than specific memory issues.
Hsi T. Wei, a psychologist leading the study, 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.” He added that older adults typically exhibit more speech dysfluencies, such as pauses or filler words like “uh” and “um,” contributing to a slower overall speech rate.
In a 2024 article for The Conversation, dementia researcher Claire Lancaster highlighted the significance 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.”
Recent advancements in artificial intelligence have also shown promise in predicting Alzheimer’s diagnoses through speech patterns, achieving an accuracy rate of 78.5 percent. Additionally, research suggests that individuals with more amyloid plaques in their brains are 1.2 times more likely to experience speech-related problems. Amyloid plaques are recognized as a hallmark of Alzheimer’s disease.
Further studies, including one from Stanford University in 2024, found that longer pauses and slower speech rates correlate with increased levels of tangled tau proteins, another key indicator of Alzheimer’s pathology. The authors of the Stanford study concluded, “This suggests that speech changes reflect the development of Alzheimer’s disease pathology even in the absence of overt cognitive impairment.”
As research continues, scientists are making strides in understanding how subtle changes in human speech can reveal significant insights into cognitive health. The groundwork laid by studies such as the one from the University of Toronto is shaping a new approach to early diagnosis and intervention for conditions like Alzheimer’s disease.
