If You Notice This in Conversations, Get Checked for Dementia

Those with dementia are less able to spot this while talking.

Dementia progressively affects memory and cognition, so it's not uncommon to notice changes in communication in those with the condition. Now, researchers are raising awareness about one particular change that dementia patients frequently display—and you may notice it during conversation. The team of experts from the University of California, San Francisco (UCSF), explain that when a person is developing dementia, they may become less able to detect one particular social cue in conversation. And for loved ones looking on, it may be the first sign that someone in your life needs a dementia screening. Read on to find out which one dementia symptom may crop up in conversation, and why it's so crucial not to overlook this form of cognitive decline.

RELATED: If You're Over 60, This Increases Your Dementia Risk by 55 Percent.

If you fail to detect lies and sarcasm, get checked for dementia.

Serious 60s elderly father and grown up adult son sitting on sofa talking having important conversation trying to solve life issues problem, different men relative people communication at home concept

The UCSF study, published in 2012 in the medical journal Cortex, found that those with frontotemporal dementia (FTD) have difficulty identifying lies and sarcasm in conversation. The research team began by gathering a group of 175 people, half of whom suffered from various forms of neurodegeneration, including FTD. The team showed the subjects videos of conversations in which the speakers would tell lies or use sarcasm, with verbal and non-verbal cues to tip off the viewer to their intentions. The subjects were then asked to analyze the statements and the speaker's intentions through "yes or no" questions about the videos.

As it turned out, those with dementia had a very difficult time distinguishing between sincere and insincere speech—unlike neurologically healthy older adults. Those who specifically suffer from FTD struggled the most to detect mistruths and discern intentions. "Patients with other forms of dementia, such as Alzheimer's disease, did better," says the study's press release.

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Detecting a lie or sarcasm is more complex—and more important—than you'd think.


The frontal lobe is considered the brain's control center, accounting for two thirds of the human brain, and responsible for behavior, personality, motor function, language, memory, and more. Your brain uses the frontal lobe when working to distinguish between truth and lies, along with many other complex forms of comprehension.

However, in those who suffer from FTD, this area of the brain is subject to degeneration as neurons and proteins known as tau become damaged or die. This is the same reason that many individuals with dementia display notable changes in behavior and outlook. This degeneration can result in "a decline in interpersonal behavior, impaired regulation of personal conduct, emotional apathy, loss of insight, and lack of social awareness," according to the UCSF study.

Though we tend to simplify our ability to detect a lie or sarcasm by deeming it "intuition," there are several complex processes going on behind the scenes, the study authors say. "A speaker who is lying wants to hide their insincerity from the listener, while someone employing sarcasm wants the listener to recognize that they are speaking insincerely. Detecting these insincere statements requires interpretation of the speaker's intention, a complex process relying on integration of semantic and syntactic comprehension, contextual and paralinguistic information processing, pragmatic knowledge, visual perspective taking, emotion reading, and theory of mind," the researchers explain.

This can have serious implications for the patient.

A senior woman sits at a table in front of a coffee while holding her head with a distressed look on her face

The consequences of this loss can be dire. When one's ability to correctly interpret and contextualize another's intentions breaks down, so do other social skills. This leads to "severely impaired communication," which can further isolate those with dementia and exacerbate their symptoms.

To make matters worse, lacking the ability to distinguish between truth, purposeful lies, and sarcasm can leave those with dementia especially vulnerable to abuse, scams, and manipulation. In fact, the authors of the study note that researchers have long been aware of dementia patients' higher likelihood to fall for a lie. "Doctors have observed evidence of this fact for years because people suffering from the disease sometimes lose significant amounts of money to online scams and telemarketers because of their blind trust," writes the UCSF team.

Get checked for dementia if you notice a problem.

doctor talking to elderly patient wearing mask

If you do suspect a problem, a doctor may be able to help you test for signs of declining social cognition. Of course, in those living with dementia, this type of self-reflection is often diminished—meaning it's also crucial for you to bring the behavior to a doctor's attention if you notice it in someone else. "Ironically, these signs are often missed because they are misattributed to depression or an extreme form of midlife crisis," explains the UCSF team.

The good news? Katherine Rankin, PhD, UCSF neuropsychologist and the senior author of the study said via press release that recognizing this symptom can help those with dementia become diagnosed earlier. "If somebody has strange behavior and they stop understanding things like sarcasm and lies, they should see a specialist who can make sure this is not the start of one of these diseases," Rankin advises.

RELATED: If You Do This, You're 50 Percent More Likely to Develop Dementia.

Lauren Gray
Lauren Gray is a New York-based writer, editor, and consultant. Read more
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