1. A documented 33% dementia chance post-stroke from an Australian study? May 2012.
2. Then this study came out and seems to have a range from 17-66%. December 2013.
3. A 20% chance in this research. July 2013.
Deterioration in key parts of the brain in neuro-degenerative diseases causes people to have problems spotting insincere communication.
Detecting lies and sarcasm is a relatively complex cognitive task.
It requires being able to simulate the other person’s mind and inferring what they must mean.
Those with dementia also find it hard to spot lies.
Dr Katherine Rankin, who led the study, said:
“These patients cannot detect lies.Scientists are always looking for ways of spotting dementia earlier, as this is the key to better treatment.
This fact can help them be diagnosed earlier.”
The study involved 175 people, some of whom had neurodegenerative diseases.
They were shown videos of people talking, who were sometimes sarcastic or told lies.
People with frontotemporal dementia found it particularly difficult to spot the lies and sarcasm.
This could provide a useful early warning sign.
Dr Rankin said:
“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.”Other early warning symptoms of dementia include a change in sense of humour:
“Changes in sense of humour could be an early sign of dementia, a new study finds.Another even more surprising sign of dementia is being unable to smell peanut butter.
A shift to preferring slapstick humour — like Mr Bean — over satirical or absurdist comedy, such as Monty Python, could be an early sign of Alzheimer’s.
Friends and relatives of those with dementia reported seeing changes around nine years before the more typical memory problems.”
The study was published in the journal Cortex (Shany-Ur et al., 2012).