Inability to Recognize Sarcasm: A Sign of Dementia?
Frontotemporal dementia is an umbrella term for a group of disorders that primarily affect the frontal and temporal lobes of the brain. These areas are generally associated with personality, behavior and language. A research team from the University of California, San Francisco, led by neuropsychologist Katherine Rankin, has shown that one sign people are developing frontotemporal dementia (FTD) is that they may have problems recognizing sarcasm in another's speech. They also may find it more difficult to detect whether or not a person is lying.
In FTD, damaged proteins accumulate in the frontal and temporal areas of the brain causing the neurons to progressively die. Since the ability to tell if someone is being sarcastic or lying depends on the functioning of the frontal lobe of the brain, the diminishment of this skill could be a signal that FTD is developing.
For the purpose of their study, Rankin's team asked participants with and without FTD, as well as some participants with other types of dementia such as Alzheimer's, to watch videos of two people talking. In the videos, one person would occasionally lie or respond in a sarcastic manner. The researchers found that healthy subjects in the group had no problem telling the sincere speakers from those who were lying or sarcastic, while the participants with FTD were far less able to do so. Patients with other forms of dementia, such as Alzheimer's disease, performed better in these tests than people with FTD. Magnetic resonance imaging (MRI) testing backed up the scientist's findings by showing deterioration in the frontal and temporal lobes of the brain.
Changes in personality symptoms of FTD
FTD can be especially difficult for spouses and children of the affected person to cope with because a major symptom of the disease is personality change. FTD can change one's gentle, mild mannered spouse into a tyrant seemingly overnight. Perhaps, if people become more aware of the seemingly small change in their loved one's ability to recognize sarcasm in a film or during a spirited conversation with a friend, they may encourage the affected person to get tested for dementia.
It's possible that the symptoms are simply caused by a medication or an infection that is making the person less cognitively sharp. However, if a neurologist does diagnose the problem as early FTD, the family would at least have more time to prepare for the inevitable changes. Information and counseling for the family about FTD, ahead of the worst symptoms, could make this dramatic change in their loved one easier cope with.
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University of California San Francisco Memory and Aging Care Center. Forms of Frontotemporal Dementia. Retrieved from http://memory.ucsf.edu/ftd/overview/ftd/forms/multiple/sd
Grady, D (2012, May 5) The Vanishing Mind: When Illness Makes a Spouse a Stranger. The New York Times. Retrieved fromhttp://www.nytimes.com/2012/05/06/health/a-rare-form-of-dementia-tests-a-vow-of-for-better-for-worse.html?_r=1&nl=todaysheadlines&emc=edit_th_20120506
National Institutes of Health. Semantic dementia; Dementia - semantic; Frontotemporal dementia; Arnold Pick's disease (Last reviewed: February 16, 2012) Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001752/