Questions have risen in the wake of the news of Bruce Willis' diagnosis of frontotemporal dementia.

Frontotemporal dementia is a form of dementia where there is a gradual degeneration or atrophy of the front temporal part of the brain. That area of the brain is responsible for language function and executive functions.

People diagnosed with this form of dementia are young, typically under the age of 65. That is one of the main differences between this type of dementia and Alzheimer's, which is usually seen in people older than 65.

So what causes this?

There are many different factors. It could be a genetic abnormality, but most times the cause is unknown.

Dr. Mill Etienne, a neurologist at Good Samaritan Hospital says while there is no way to prevent dementia, diet and exercise play a huge role. The healthier you eat, and the more active you are, the better your overall health outcome will be.

People with this form of dementia will experience a gradual loss of language. They might have trouble understanding people or trouble finding the right words and getting them out, but there will be other changes as well.

"You might see problems with memory, you might see behavioral changes where the person is engaging in social behavior that's different from their baseline, from what they normally do. Maybe all of a sudden, the person is outgoing, and maybe doing inappropriate things, being more disinhibited, trouble with executive function," Etienne says.

While there is no cure to frontotemporal dementia, there are many different therapies that can help. Etienne says he advocates for his patients to join one of the many support groups that are out there for people who have this diagnosis. One might feel alone, but the truth is one is not.