Suddenly developing a bizarre sense of humor may be an early warning sign of dementia, according to a new U.K. study.

University College London researchers surveyed friends and relatives of 48 people with frontotemporal dementia and found that many noticed a change in patients' humor years before they were diagnosed with dementia, BBC News reported.

The changes included inappropriate laughter in response to tragic events, according to the study in the Journal of Alzheimer's Disease.

Frontotemporal dementia is one of the rarer forms of dementia and affects the area of the brain involved in personality and behavior, BBC News reported.

Further research is needed to determine how and when changes in a person's sense of humor could be an early warning of dementia, experts say.