Matthew Perry tributes to The Whole Nine Yards co-star Bruce Willis after stepping away from acting

The world learned on Wednesday that Hollywood legend Bruce Willis, 67, would retire due to his diagnosis of aphasia, a potentially devastating condition that causes a person to lose communication skills.

Willis’ family announced that the condition would cause the Die Hard star to step away ‘from the career that has meant so much to him.’

Around one million Americans suffer from the condition, the National Institutes of Health reports, and around 180,000 people are diagnosed with it every year.

It can manifest itself in multiple ways, and is often either the result of a head injury, a stroke, a tumor or other brain deterioration.

Aphasia can be devastating as well, with experts saying it causes depression in over a third of cases, can lead to personality shifts and can even alienate friends and family from the affected person.

Other famous examples of aphasia include former Arizona Congresswoman Gabby Giffords and Game of Thrones star Emilia Clarke.

‘Imagine being dropped in a country where you do not speak the language – cannot understand, read, write or speak. It would impact all of your interactions – this is what it is like to have aphasia,’  Darlene Williamson, president of the aphasia association, told DailyMail.com.

While it is impossible to say for Willis in particular how drastically the condition has effected him and his behavior, Williamson reports that it can often be devastating for patients.

‘The consequences of living with a language impairment can alter someone’s behavior and outlook on life,’ Williamson said.

‘Approximately 35 percent of individuals with aphasia experience some depression.’

The cause of the condition, which is often some sort of traumatic brain injury or a stroke, can lead to massive personality shifts.

‘[Aphasia is] difficulty with language that comes about from some kind of injury to the brain. The most common source is stroke… but it could come from any other type of damage,’ Dr Brenda Rapp, a cognitive scientist at Johns Hopkins University, told DailyMail.com.

Certain infections that impact the brain’s language centers can cause aphasia to form as well, along with cognitive decline and deterioration associated with dementia.

The condition can make it very hard for an actor like Willis to continue in his career, as just the process of speaking out lines can become a challenge.

‘It would surely be difficult,’ Williamson said about attempting to continue acting while afflicted with the condition.

‘Aphasia affects comprehension of language, speaking, as well as reading and writing. There are varying levels of severity which would be another determining factor. It may not be impossible, but acting would require extra accommodations.’

There are four common types of aphasia that make up a vast majority of cases: fluent – often called Wernicke’s; non-fluent – known as Broca’s; anomic; and Primary Progressive Aphasia.

Rapp explained that there are different forms of the condition because each represents a different type of breakdown in the process of communication.

Whether it is the ability to translate thoughts into proper words, the ability to physically say words,  or the ability to interpret and understand speech from others, each part of communication is a complex process, and even slight brain damage can cause issue.

While the condition does cause communication failures, Rapp notes that the person themselves is still the same.

Their thoughts, beliefs and feeling towards their loved ones remain, even if it can be frustrating and alienating for both the aphasia patient and those around them to deal with this condition.

Willis’ family did not reveal what type he was facing, or how severe of a case he had, or what was the root cause found for the condition.

According to the Stroke Association, a UK based group, those who suffer Wernicke’s aphasia have the ability to string together long sentences of words, but will often say things in a way that they do not make sense, or even use made up words.

They will also suffer from impaired reading and writing ability, and may have trouble understanding clear verbal communication towards them.

One example used by Rapp is that a person may misunderstand the sentence ‘John kicked the dog’.

While the average person would clearly understand who kicked who in that scenario, a person dealing with this type of the condition may struggle to figure out whether John or the dog was the person that did the kicking.

Broca’s aphasia will often cause a person to forget words or put together a proper string of words even when their brain can fully understand what they want to say.

A person suffering from this type of the condition will often use simple, short, sentences to get across speech as they are unable to properly say what they want to at times.

The Stroke Association says that these sentences will often be of around four words or less.

A person suffering from Broca’s aphasia will also struggle with writing, but their reading ability is left unaffected.

Someone suffering from anomic aphasia may suffer to find specific verbs and nouns that they need to get their point across, and will speak very vaguely.

This may also translate into their writing, where they will just not be able to generate the correct words necessary to say what they would like to say.

Primary Progressive Aphasia aphasia damages a person’s ability to communicate in virtually every single way.

A person suffering from this version of the condition will have trouble speaking, reading and writing.

Their ability to process and understand someone that is speaking to them is damaged as well.

Doctors can often detect aphasia via either an MRI or CT scan, and will be able to pinpoint the exact part of the brain that is causing the issue.

There is no way to fix or cure the condition entirely, but patients will often undergo speech therapy to help rebuild their language skills.

‘There’s not a lot of progress [with medication for the condition]… the treatment for aphasia is speech therapy,’ Rapp said.

She noted that in some cases a person may undergo electric stimulation therapy alongside speech therapy in order to ‘get the most’ out of the experience.

Williamson said that ‘strong family support is a critical piece of living successfully with aphasia.’

It is not always permanent, though, and how long it lasts and how severe it is often depends on how bad the damage to the brain is.

Stroke victims in particular that suffer aphasia can regain their speech, and often within only a few weeks.