As we get older, we may notice that it takes us longer to find the right words during a conversation, and we may worry that this could be a symptom of cognitive decline or dementia. However, a recent study by Baycrest – a world leader in aging and brain health – and the University of Toronto has found that speaking speed is a more relevant indicator of brain health than word-finding difficulty, which appears to form part of the natural aging process.
This study is one of the first to examine differences in natural speech and brain health among healthy adults. “The results show that changes in speaking speed may reflect changes in the brain,” said Dr. Jed Meltzer, Canada Research Chair in Interventional Cognitive Neuroscience at Baycrest and senior author of the study. “This implies that speaking rate should be included in standard cognitive assessments to help doctors detect cognitive decline more quickly and help older adults maintain their brain health as they age.”
A key indicator of changes in brain health
In the study, 125 healthy volunteers between the ages of 18 and 90 completed three different assessments. The first consisted of a picture-naming game, in which they had to answer questions about pictures while ignoring distracting words they heard through headphones. For example, upon seeing a picture of a mop, they could be asked, “Does it start with ‘e’?” while they heard the word “broom” as a distraction. In this way, the researchers were able to test the participants’ ability to recognize the image and remember its name.
Participants were then recorded describing two complex images for 60 seconds each. Their linguistic performance was later analyzed using AI-based software, in collaboration with Winterlight Labs. Among other things, the researchers examined the speed at which each participant spoke and how many pauses they made.
Finally, study participants completed standard tests to assess mental abilities that tend to decline with age and are linked to dementia risk, specifically, executive function, which is the ability to handle conflicting information, stay focused, and avoid distractions.
As expected, many skills declined with age, including word-finding speed. Surprisingly, although the ability to recognize an image and remember its name worsened with age, this was not associated with a decline in other mental abilities. The number and length of pauses participants took to find words was not linked to brain health.
“Speech rate should be included in standard cognitive assessments to help doctors detect cognitive decline more quickly”
Instead, how quickly participants could name pictures predicted how quickly they spoke overall, and both were linked to executive function. In other words, it wasn’t the word-finding pause that showed the strongest link to brain health, but the speed of speech around the pauses. The results have been published in Aging Neuropsychology and Cognition.
Although many older adults are concerned about their need to pause to look up words, these results suggest that this is a normal part of aging. On the other hand, the slowing of normal speech, regardless of pauses, may be a more important indicator of changes in brain health.
In future studies, the research team could conduct the same tests with a group of participants over several years to examine whether speaking rate is truly predictive of brain health in individuals as they age. In turn, these results could support the development of tools to detect cognitive decline as early as possible, allowing doctors to prescribe interventions to help patients maintain or even improve their brain health as they age.
