Potential Clues to Alzheimer’s in Speech Patterns

Recent research indicates that the way a person speaks may provide early signs of Alzheimer’s disease, although the specific aspects of speech crucial for diagnosis remain unclear.

A 2023 study has found that as we age, how we articulate our thoughts—particularly the speed of our speech—might be more telling than the words themselves. Researchers from the University of Toronto propose that a slower pace of everyday conversation could signal cognitive decline more effectively than simply struggling to retrieve words.

“Our findings suggest that variations in overall speaking speed could mirror changes occurring in the brain,” explained cognitive neuroscientist Jed Meltzer when the study came out.

“This points to the need for speech speed to be included in standard cognitive assessments, as it may aid clinicians in detecting cognitive decline sooner and help older adults maintain their brain health.”

Lethologica, often referred to as the “tip of the tongue” phenomenon, is something people of all ages experience. However, it tends to become more prevalent with age, especially after hitting 60.

To delve deeper into this, researchers gathered a group of 125 healthy adults ranging from 18 to 90 years old and had them describe various scenes in detail.

The participants then viewed images of common objects while listening to audio designed to either assist or mislead them. For example, if they saw a broom, the audio could say “groom,” helping them remember through rhyme. Conversely, it might also say “mop,” leading them to some confusion.

The quicker a person’s natural speech rate during the initial task, the faster they were able to come up with answers in the subsequent task.

This aligns with what’s known in psychology as the “processing speed theory,” which essentially posits that a general slowdown in cognitive processing is central to cognitive decline, rather than just issues with memory functions.

“It’s clear that older adults take significantly longer than younger ones to complete various cognitive tasks,” noted a team led by psychologist Hsi T. Wei from the University of Toronto. “In everyday speech, older individuals also tend to have more interruptions, like “uh” and “um,” and generally speak more slowly.”

In a 2024 piece for The Conversation, dementia researcher Claire Lancaster remarked that the Toronto study “opens exciting doors… showing it’s not just what we say, but how quickly we say it, that can indicate cognitive changes.”

Some AI algorithms have recently been able to use speech patterns to predict Alzheimer’s diagnoses with accuracy rates around 78.5 percent.

Other studies suggest that patients exhibiting more amyloid plaques in their brains may be 1.2 times more likely to encounter speech-related difficulties. Amyloid plaques are a recognized marker of Alzheimer’s, along with tau tangles.

A 2024 study from Stanford University discovered that longer pauses and slower rates of speech correlated with higher levels of tangled tau proteins.

Neuroimaging data from 237 cognitively healthy participants indicated that those with more tau burden tended to speak more slowly and take longer pauses overall.

Interestingly, participants with more tau evidence didn’t necessarily show greater challenges in answering memory recall tests. Perhaps those experiencing early memory problems still know the answers; they are just taking longer to articulate them, which reflects in their speech.

If this holds true, analyzing speech patterns during memory tests could unveil new insights regarding a person’s neurological health that traditional assessments might miss.

The 2023 study concluded that shifts in speech may indicate the development of Alzheimer’s pathology, even when no obvious cognitive impairment is present.

They suggest that examining speech during memory recall tasks could be particularly valuable.

Longitudinal studies are needed to track individuals who show slower performance on memory tests, to determine if they subsequently develop dementia or cognitive challenges.

It’s important to note that just because someone shows elevated levels of tau tangles or amyloid plaques does not mean they are destined to develop Alzheimer’s.

Overall, scientists are making strides in understanding the nuances of human speech and what our expressions might reveal about brain health.

The 2023 study was published in Aging, Neuropsychology, and Cognition.