Alzheimer's, Dementia & Mental Health
Inability of Senior Citizens to Detect Sarcasm, Lies
May Be Early Sign of Dementia
‘These patients cannot detect lies’ – ‘This fact
can help them be diagnosed earlier’
April 15, 2011 – While millions of dollars are
being spent on scientific research to find an early detection system for
Alzheimer’s disease and other dementias, scientists at the University of
California, San Francisco think they have found a simple method. They
say senior citizens unable to detect sarcasm and lies are likely victims
of dementia.
By asking a group of older adults to analyze videos
of other people conversing - some talking truthfully, some insincerely -
a group of scientists at the University of California, San Francisco has
determined which areas of the brain govern a person's ability to detect
sarcasm and lies.
Some of the adults in the group were healthy, but
many of the test subjects had neurodegenerative diseases that cause
certain parts of the brain to deteriorate. The UCSF team mapped their
brains using magnetic resonance imaging, MRI, which showed associations
between the deteriorations of particular parts of the brain and the
inability to detect insincere speech.
"These patients cannot detect lies," said UCSF
neuropsychologist Katherine Rankin, PhD, a member of the UCSF Memory and
Aging Center and the senior author of the study. "This fact can help
them be diagnosed earlier."
The finding was presented Thursday, April 14, 2011,
at the 63rd Annual Meeting of the American Academy of Neurology in
Hawaii, by Rankin and her postdoctoral fellow Tal Shany-Ur, PhD. The
title of their presentation was, "Divergent Neuroanatomic Correlates of
Sarcasm and Lie Comprehension in Neurodegenerative Disease."
In a presentation today at the 63rd Annual Meeting
of the American Academy of Neurology in Hawaii, Rankin and her
postdoctoral fellow Tal Shany-Ur, PhD, will show the data, which
suggests that it may be possible to spot people with particular
neurodegenerative diseases early just by looking for the telltale sign
of their inability to detect lies.
“We have to find these people early,” said Rankin.
In general scientists believe that catching people early in the disease
will provide the best opportunity for intervention when drugs become
available.
The study is part of a larger body of work at
UCSF’s Memory and Aging Center examining emotion and social behavior in
neurodegenerative diseases as tools for better predicting, preventing,
and diagnosing these conditions.
Dementia and Disbelief
The ability to detect lies resides in the brain's
frontal lobe. In diseases like frontotemporal dementia, this is one of
the areas that progressively degenerates because of the accumulation of
damaged proteins known as tau and the death of neurons in those areas.
Because the frontal lobes play a significant role
in complex, higher-order human behaviors, losing the ability to detect
lies is only one of several ways the disease may manifest. The first
signs of the disease may be any number of severe behavioral changes.
People sometimes behave in socially inappropriate ways or undergoing
fundamental shifts in outlook -- switching political affiliations or
changing religions, for instance.
Ironically, these signs are often missed because
they are misattributed to depression or an extreme form of midlife
crisis.
Hoping to increase the tools available for doctors
and caregivers to recognize the early signs of the disease, the UCSF
team focused on the fact that people with frontotemporal dementia often
lose the ability to detect sarcasm and lies. 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.
People who age normally without suffering
neurodegeneration, on the other hand, generally do not suffer a
significant decline in their ability to understand sarcasm and
deception.
But the question was how solid this association is.
Would the inability to detect sarcasm and lies actually match the brain
regions hit early in these diseases?
Assess, Lies, and Videotape
In order to answer this question, the UCSF team
worked with 175 people, more than half of whom had some form of
neurodegeneration. They showed them videos of two people talking, one of
whom would occasionally tell lies or use sarcasm -- a fact that was
apparent in the videos from verbal and non-verbal cues. Then the test
subjects were asked yes/no questions about videos.
Healthy older subjects in the study could easily
distinguish sincere from insincere speech. However, the subjects who
had frontotemporal dementia were less able to discern among lies,
sarcasm, and fact. Patients with other forms of dementia, such as
Alzheimer’s disease, did better.
To associate the detection inability with
neurodegeneration, the UCSF team used MRI to make extremely accurate
maps of the brains of the subjects in the study. This allowed them to
measure the volumes of different regions of the brain showing that the
sizes of those regions correlated with the inability to detect sarcasm
or lying.
According to Rankin, the work should help raise
awareness of the fact that this extreme form of gullibility can actually
be a warning sign of dementia -- something that could help more patients
be correctly diagnosed and receive treatment earlier in the long run.
"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," said
Rankin.
The presentation, "Divergent Neuroanatomic
Correlates of Sarcasm and Lie Comprehension in Neurodegenerative
Disease" by Tal Shany-Ur, Pardis Poorzand, Scott Grossman, Stephen M.
Wilson, Bruce L. Miller, Katherine P. Rankin is at 10:30 a.m. Pacific
time on Thursday, April 14, 2011.
Other co-authors of the study arePardis Poorzand
and Scott Grossman and Stephen M. Wilson and Bruce L. Miller, of the
UCSF Memory and Aging Center.
UCSF says it is a leading university dedicated to
promoting health worldwide through advanced biomedical research,
graduate-level education in the life sciences and health professions,
and excellence in patient care.
