An altered sense of humor — including a switch away from complicated, subtle comedy towards more obvious simple jokes and laughing at inappropriate situations — could be an early sign of dementia, a new study suggests.
"Satirical humor uses sophisticated brain processes similar to those involved in problem-solving," lead author, Camilla Clark, MD, University College London, United Kingdom, commented to Medscape Medical News. "The process of how we decipher jokes involves an expectation of what is supposed to happen and then adjustment when something different happens. The brain has to switch fast. Our results suggest that this process appears to be affected early in the development of dementia, with patients often not appreciating satirical humor anymore and preferring more obvious slapstick comedy instead."
The researchers also found that patients with frontotemporal dementia in particular often exhibited inappropriate humor. Dr Clark said, "This could manifest itself as laughing at situations which are not funny — like at a funeral, or when someone hurts themselves or at media coverage of a disaster."
These changes were also reported to have occurred several years before other symptoms of dementia developed, leading the authors to suggest that change in humor could be one of the first indications that a patient may be developing dementia.
Senior author of the study, Jason Warren, MD, University College London, United Kingdom, commented: "GPs [general practitioners] need to look out for a clear change in patient's sense of humor and be aware that this could signal a problem. I'm not referring to just the odd joke falling flat but more the situation when the family may be perplexed that the patient's sense of humor has markedly altered."
The study was published online in the Journal of Alzheimer's Disease on November 10.
For the analysis, researchers asked close relatives or carers of 48 patients with various types of dementia to complete a semi-structured questionnaire rating the patient's reaction to different comedy programs, including slapstick, satirical, and absurdist humor.
They were asked to rate the patient's preference at the current time and before dementia had developed. They were also asked some open-ended questions about situations the patients found amusing and their sense of humor in general. Responses were compared with those from 21 healthy age-matched controls.
Results showed that all patient groups liked satirical and absurdist comedy significantly less than did healthy controls, and this pattern was often reported before dementia actually developed: on average 9 years before other symptoms were reported. Liking slapstick comedy did not differ between groups.
Altered humor responses were significantly more frequent in patients with frontotemporal and semantic dementia than in patients with progressive nonfluent aphasia or Alzheimer's disease.
Dr Warren noted: "In our study, about half the patients with Alzheimer's showed a change in humor whereas this occurred in virtually all those with frontotemporal dementia."
"In addition to GPs asking people about this, I think the general public should also be aware of changes in what their older relatives find funny. If there is a marked shift in this — if they used to really like satirical comedy but they start not to understand the jokes — that could be a warning sign of early dementia," he said.
He added: "We are not saying that everyone who exhibits a change in their humor will develop dementia. There could be many other reasons for that happening. But our study is the first quantitative demonstration of change of humor in relation to dementia."
Dr Clark acknowledged that the current study was small and the results need to be validated. The researchers are doing this through an international study involving children of patients with frontotemporal dementia, which has a strong genetic component. Dr Clark explained: "Our current study is retrospective and therefore may be subject to bias, but the new international collaboration will follow people with a high risk of developing dementia and will compare changes in humor before and after the onset of dementia."
This work was funded by the Wellcome Trust, the UK Medical Research Council, and the National Institute for Health Research Queen Square Dementia Biomedical Research Unit.
J Alzheimers Dis. Published online November 10, 2015. Full text