The family of US actor Bruce Willis has announced that his previous diagnosis of the cognitive condition aphasia has developed into frontotemporal dementia.

In an update shared online, the family said they had the “deepest gratitude for the incredible outpouring of love” following the initial news.

Here we take a closer look at the condition, known as FTD.

– What is FTD?

FTD is an “umbrella term” for a group of dementias that mainly affect the frontal and temporal lobes of the brain, which are responsible for such things as personality, behaviour, language and speech, according to Dementia UK.

The charity said that FTD is a “rare” form of dementia that affects only around one in 20 people with a dementia diagnosis.

Willis’s family first announced his diagnosis of aphasia in March last year.

– What causes FTD?

According to Dementia UK, FTD is caused by an “abnormal build-up of proteins within the brain” which damages the cells.

It is not known why this build-up occurs but is thought to have a genetic link in about one third of people with the diagnosis.

FTD is most common in people aged 40 to 60 but can also affect younger or older people, the charity said.

Willis is 67 years old.

The NHS says that, like other forms of dementia, FTD tends to develop slowly and get gradually worse over the years.

– What are the symptoms of FTD?

There are two types of FTD – behavioural variant FTD (bvFTD) and primary progressive aphasia (PPA).

BvFTD, which results from damage to the frontal lobes of the brain, mainly causes problems with behaviour and personality.

PPA, when damage occurs to the temporal lobes on either side of the head nearest the ears, causes language problems.

Alzheimer’s UK says that FTD symptoms are “very different” to other more common types of dementia, such as day-to-day memory loss – adding that in the early stages of the disease, many people can still remember recent events.

In their statement on Thursday, Willis’s family said that challenges with communication are just one symptom of the disease the actor was facing.

The NHS says FTD can also cause physical problems including slow or stiff movements, loss of bladder control, loss of bowel control, muscle weakness or difficulty swallowing.

– How is FTD treated?

According to Dementia UK, there is no prevention or cure for FTD and it is often best to “focus on practical strategies to help the person live as well as possible with the diagnosis”.

Willis’s family said that the lack of treatment for the disease was “a reality that we hope can change in the years ahead” with further research.

They added that as the actor’s condition advances, they hope media attention will be used to raise more awareness of FTD.

“Bruce always believed in using his voice in the world to help others, and to raise awareness about important issues both publicly and privately,” they said.

“We know in our hearts that – if he could today – he would want to respond by bringing global attention and a connectedness with those who are also dealing with this debilitating disease and how it impacts so many individuals and their families.

“Bruce has always found joy in life – and has helped everyone he knows to do the same.”

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