Bruce Willis’ frontotemporal dementia (FTD) diagnosis is bringing more attention to the rare condition.

For World Frontotemporal Dementia Awareness Week, Willis’ wife, Emma Heming Willis, and the Association for Frontotemporal Degeneration's CEO Susan Dickinson spoke on the "TODAY" show about the actor’s health status and shared details of the disease.

Dickinson, who is based in Pennsylvania, explained what happens to patients facing FTD, mentioning how the path to a diagnosis can be "one of the most confusing parts."

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"Because it is less common, most doctors aren’t familiar with it," she said. 

"It can take almost four years for people to get diagnosed on average."

A photo of Bruce Willis kissing Emma Heming

Bruce Willis’ wife, Emma Heming Willis, is opening up about the actor’s health status and details of his disease. (Larry Busacca/VF14/WireImage)

Often, Dickinson revealed, patients are misdiagnosed with other conditions such as bipolar disorder, depression, Alzheimer’s disease or even Parkinson’s or ALS.

Heming Willis said FTD is different from these other cognitive diseases, as the condition can also affect movement and speech.

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Dickinson added that it can also impact behaviors, personality and executive functioning, which includes the ability to plan ahead, meet goals, display self-control, follow multistep directions and focus despite distractions, citing Harvard University's Center on the Developing Child.

FTD can be indicated by "unexplained changes" in behavior and personal presentation, the expert mentioned.

Brain scan

Dickinson explained how the disease can impact self-insight due to its location in the brain's frontal and temporal lobes. (iStock)

"So, somebody who normally speaks absolutely fine has trouble putting their thoughts into meaningful sentences," she said. "Or they may lose the meaning of a specific word."

"Maybe a person who always managed the family’s finances all of a sudden has trouble balancing a checkbook."

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Emerging problems at work can also be a warning sign, Dickinson added.

"Somebody who’s always performed well is either making poor decisions or just isn’t completing tasks," she said.

Emma Heming Willis looks to her right in a blue dress with black mesh as Bruce Willis looks to his left wearing a dark suit on the carpet

Emma Heming Willis says she doesn't want her children to feel "stigma or shame" surrounding their father's dementia diagnosis. (Kris Connor/FilmMagic/Getty Images)

Heming Willis admitted that it’s "hard to know" if her husband is aware of what’s going on with him.

Because the disease can begin in the frontal or temporal lobes of the brain, Dickinson confirmed that it can affect self-insight.

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"We really don’t know," she said. "Some people, the first thing they lose is any understanding that they themselves have changed, and other people retain that for a long time."

FTD can be passed on genetically, Dickinson noted, as the genetic mutation is present in about 25% of people; but the condition is sporadic in most patients.

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She added, "We do not know yet what causes the condition, which is one of the challenges."

FTD accounts for an estimated 10% to 20% of all dementia cases, according to The Association for Frontotemporal Degeneration.

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