Elderly people who are increasingly unable to detect sarcasm or lies may be exhibiting early signs of dementia/neurodegenerative diseases, according to University of California scientists. The new research suggests that it might be possible to spot certain neurodegenerative diseases by looking for surprising gullibility in someone who otherwise may seem healthy. This connection has been somewhat obvious for years, as elderly people are sadly more easily suckered by scam artists. (Not to say that being an easy target for a con means one has a neurodegenerative disease.) In this latest work though, he UCSF team used brain scans to show that damage and deterioration in certain regions of the brain correlate with an inability to known when someone isn't being sincere. From UCSF Medical Center:

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.