What is frontotemporal dementia?

Frontotemporal dementia, or FTD, is a group of brain disorders caused by damage to nerve cells in the frontal and temporal lobes, which shrink as the cells die. The National Institute on Aging says it can change behavior and personality, language, or movement. It tends to start younger than other dementias: roughly 60 percent of people with FTD are 45 to 64 years old.

It is hard to predict. The National Institute on Aging says some people live more than 10 years after an FTD diagnosis, while others live less than two years. The disorders are progressive: early on a person may have just one type of symptom, and other symptoms appear as more of the brain is affected. A specialist can speak to an individual's likely course.

Sometimes. The National Institute on Aging estimates that about one third of FTD cases are inherited, passed from parent to child through a variant in a gene such as MAPT, GRN or C9orf72. These variants can often be found through genetic testing. In most other cases the cause is unknown, though people with a family history of FTD are more likely to develop it.

Usually not at first. The Alzheimer's Association says memory loss is more prominent early in Alzheimer's than in early FTD, where changes in behavior or language usually come first. Advanced FTD often does cause memory loss as well. Getting lost in familiar places is also more common in Alzheimer's than in FTD, and people with FTD tend to have more trouble making sense when they speak.

There is no cure for FTD and no treatment to slow it, but symptoms can be managed. The National Institute on Aging says a team of doctors, nurses, and speech, physical and occupational therapists can help. Antidepressants are often prescribed for disinhibition and impulsive behavior, and speech therapy helps with language problems. Always consult a doctor before changing, adding or stopping a medicine.