Inability to Detect Sarcasm May Be Early Dementia Sign People who can't pick up on lies, tone could be at risk By John Johnson, Newser Staff Posted Apr 15, 2011 4:36 PM CDT 17 comments Comments An inability to detect lies or sarcasm could be an early sign of dementia, new research suggests. (Shutterstock) (Newser) – It might be a low-tech way to diagnose the early stages of certain types of dementia: Look for people no longer able to detect sarcasm or lies. University of California researchers found that people with frontotemporal dementia fared poorly in tests measuring gullability, reports UCSF. Anecdotal evidence of seniors getting bilked in online or telemarketing scams have been around for years, and the study used MRI scans to show the correlation with patients who have specific types of brain detorioration. "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," says the senior author, neuropsychologist Katherine Rankin.