Scientists say the speed of a person’s speech, not just how quickly they can recall a word, could be an early warning sign of dementia.
Early signs of Alzheimer’s disease — which affects more than six million Americans — may include changes in talking speed that reflect underlying brain decline.
Researchers at the University of Toronto turned a picture-naming task into a game to measure how quickly 125 adults aged 18 to 85 could retrieve words.
In the study, people who were slow at naming pictures in the game were also the ones who spoke more slowly and used more ‘ums’ and ‘uhs’ in everyday conversation, a sign that the brain’s processing speed affects everything from timed tasks to casual conversation.
But the strongest link between speech and brain health was the speed at which the words came out when a person was talking, not the hesitations or length of gaps between words.
How quickly someone could name a picture matched how quickly they spoke in general, and both were tied to executive function, which controls how quickly the brain can take in information, make sense of it and respond.
A general slowness in getting words out, whether in a naming game or natural conversation, appeared to reflect the cognitive processing speed that slows with age and may signal early changes in the brain.
Unlike traditional memory tests that simply track whether someone answers correctly, speaking speed may offer a more sensitive early clue to cognitive decline.
Speaking speed itself — not the number of ‘uhs’ and ‘ums’ in a person’s sentence — was the strongest link to brain health. How quickly someone named a picture matched how quickly they spoke and both were tied to the brain’s ability to process information and respond (stock)
Dr Jed Meltzer, a neuroscientist at the Baycrest Foundation, a globally recognized leader in aging and brain health in Toronto, and the lead author on this study, said: ‘This suggests that talking speed should be tested as part of standard cognitive assessments to help clinicians detect cognitive decline faster and help older adults support their brain health as they age.’
Most standard cognitive tests, like the Montreal Cognitive Assessment (MoCA) or Mini-Mental State Exam (MMSE), only consider if a person gets the answer right, not how long it takes them to get there.
For their study, published in the journal Aging, Neuropsychology, and Cognition, Canadian researchers recruited 125 healthy adults between 18 and 85 years old and had them play a simple online game.
Players saw pictures of everyday objects, such as a dog, a car and a spoon, and had to quickly hit a button depending on how the word ended.
While they did this, they heard audio distractions; sometimes a related word like ‘cat’ when the picture was a dog, sometimes a word that sounded similar, like ‘fog’ for dog or they may be asked ‘Does it end in ‘p’’ while they hear the word ‘broom’. The computer tracked how fast they responded.
The participants also described two busy, cartoon-like scenes while being recorded. Researchers then used speech analysis software to count their ‘ums,’ ‘uhs,’ pauses and how fast they talked. Their language was then analyzed with AI software.
Participants then completed standard tests of working memory, impulse control and verbal fluency, such as naming as many animals as possible in 60 seconds or remembering words while judging sentences.
By comparing all this data, the researchers could see how speed in the game matched real-life speech patterns and cognitive function across someone’s life.
As expected, word-finding speed slowed with age. But while picture-naming accuracy also declined, it was not tied to a broader drop in other mental skills.
Fast talkers were fast in the game while slow talkers were slow in the game. And both were linked to executive function, the brain’s command center for processing information.
The researchers tested three leading theories on why word-finding slows with age. One blames a weakened ability to block out irrelevant words.
Another points to a breakdown between thinking of a word and saying it. The third — called processing speed theory — says it’s simply a matter of general slowdown.
This study found evidence that general slowdown is the key driver, not specific language breakdowns.
That suggests that improving processing speed through cognitive training or other interventions might help preserve language function, not just reaction time.
A growing body of research shows that speech is a hallmark warning sign of neurodegenerative diseases like Alzheimer’s and frontotemporal dementia. The ability to speak requires several regions of the brain to work in concert.
The hallmarks of Alzheimer’s disease — amyloid beta plaques and fibrous tangles of tau — are present years before signs of cognitive impairment manifest.
A separate 2025 study in the journal Alzheimer’s & Dementia, from the sweeping Framingham Heart Study, suggested how a person pauses and structures their sentences can reveal the early buildup of these disease markers.
The study looked at brain scans of 238 cognitively healthy adults 32 to 75. People with more pauses and slower speech during a memory recall task had higher levels of tau in brain regions known to be affected early on in the disease, including those critical for memory and language.
Researchers noted that while many older adults become concerned about their brain health when they notice using more fillers like ‘uh’ and ‘um’ or pauses between words, the true mark of cognitive aging is likely a slowdown of regular speech regardless of pausing.
While six million Americans have Alzheimer’s disease, roughly 10 million have mild cognitive impairment, often a precursor to a dementia diagnosis. The disorders primarily affect adults 65 and over, though cases of early-onset Alzheimer’s can strike people in their 40s.
