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Inability to Spot Lies May Warn of Dementia


Does someone you love seem increasingly gullible? Don’t be too quick to dismiss this as a normal sign of aging. Here’s why…

A recent study included 175 people ages 45 to 88, more than half of whom were in the early stages of some type of neurodegenerative disease that causes certain parts of the brain to deteriorate. Participants watched videos of two people talking. In addition to truthful statements, the video dialogue included sarcasm and lies, plus verbal and nonverbal clues to help participants pinpoint the false or insincere statements. Participants then answered yes/no questions about the video… and researchers compared their scores with results of MRI scans that measured the volume of different brain regions.

Results: Cognitively healthy people easily picked out the lies and sarcasm in the video, as did most participants with certain neurodegenerative diseases, including Alzheimer’s. However, participants whose brain scans showed degeneration of the frontal and temporal lobes, a condition called frontotemporal dementia—which is as common as Alzheimer’s disease among people under age 65—found it very difficult to distinguish factual statements from untruthful or sarcastic ones.

Bottom line: Increasing inability to recognize deception or sarcasm merits a consultation with a neurologist, especially if accompanied by other possible symptoms of frontotemporal dementia, such as severe changes in behavior and/or personality—yet often these are mistaken for signs of depression, a midlife crisis or normal aging. Early diagnosis of frontotemporal dementia may maximize treatment options and help protect patients vulnerable to being scammed due to their blind trust.

Source: Katherine P. Rankin, PhD, is a neuropsychologist and associate professor of neurology at the University of California, San Francisco, Memory and Aging Center and coauthor of a study presented at a meeting of the American Academy of Neurology. Date: October 20, 2011 Publication: Bottom Line Health
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