London - An increasingly warped sense of humour could be an early warning sign of dementia, experts say.
A British study has found sufferers of some forms of the disease had a change in humour almost a decade before they were diagnosed.
Though dementia is more commonly associated with memory loss, researchers say telltale signs could include laughing inappropriately at tragic events and being amused by slapstick while losing interest in satire.
The discovery could lead to earlier diagnosis – and help doctors distinguish between forms of the disease. Study author Camilla Clark, of University College London, said: “Humour could be a particularly sensitive way of detecting dementia because it puts demands on so many different aspects of brain function, such as puzzle-solving, emotion and social awareness.”
Dr Clark quizzed relatives and close friends of 48 people with dementia about what the sufferers found funny – and whether their taste had changed. The answers were compared to those of 21 healthy people of a similar age.
Some patients had Alzheimer’s and others had frontotemporal dementia – the most common form of the disease in under-55s, which usually begins with behavioural changes such as loss of inhibition and difficulty decision-making.
Analysis revealed those with dementia found humour requiring complex thought – including satirical shows such as Yes, Minister and the absurdist humour of Monty Python – less entertaining than they had before.
The sufferers also enjoyed the slapstick comedy of Mr Bean and The Benny Hill Show more than others – something apparent an average of nine years before their dementia diagnosis.
Those with the most common type of frontotemporal dementia experienced a second change – inappropriate laughter. They laughed at mundane things such as a dog barking or a badly parked car, or found humour in the misfortune of others, with everything from a child falling off a bike to natural disasters raising a smile.
Dr Clark said: “These were marked changes – completely inappropriate humour well beyond the realms of even distasteful humour. For example, one man laughed when his wife badly scalded herself.”
Lee Pearse, of Sheffield, noticed changes in his mother Valerie – who was not part of the study – four years before she was diagnosed with frontotemporal dementia. She was initially thought to be depressed.
He said: “She’d always been very loving and family-focused but became increasingly uninvolved and emotionless. Mum’s behaviour became more and more erratic and we began to question the diagnosis.
“She’d forget family birthdays, laugh if someone had an accident or heard someone was unwell and was even sacked from her job – all completely out of character.”
It is thought the changes are an indication of the havoc dementia wreaks in the brain. Emotional disconnection may lead to those with the frontotemporal form of the disease developing what seems to be a nasty streak.
Dr Simon Ridley, of charity Alzheimer’s Research UK, said: “This study highlights the importance of looking at the myriad different symptoms.” Dr Rob Buckle, of the Medical Research Council, which part-funded the study, said the findings would “allow us to build up a full picture of the changes that people experience in the early stages of dementia and as the condition progresses, guiding both improved and earlier diagnosis and the delivery of care”.
Daily Mail