Being able to communicate — from finding the right words to just being able to read and write — is something that most people take for granted.

However, for those who suffer from aphasia — a cognitive disorder that affects a person’s ability to speak and understand others — communicating can be a challenging task.

The health condition came to light on Wednesday after Emma Heming Willis, wife of actor Bruce Willis, shared in an Instagram post that her husband has aphasia. In the post, Emma said the condition is affecting his “cognitive abilities” and that he is stepping away from his career because of it.

So what is aphasia?

Aphasia is “a language disorder that results from damage to the left hemisphere of the brain,” Jennifer Brello, a clinical associate professor at the Ohio State University and director of the OSU Aphasia Initiative, tells Yahoo Life. “It can cause difficulty using words and sentences, understanding language, reading and writing.”

The disorder can range from mild to severe. According to the National Aphasia Association (NAA): “It may affect mainly a single aspect of language use, such as the ability to retrieve the names of objects, or the ability to put words together into sentences, or the ability to read. More commonly, however, multiple aspects of communication are impaired, while some channels remain accessible for a limited exchange of information.”

There are also different types of aphasia. To help determine which type a patient has, there are three factors to look out for, according to the Cleveland Clinic: speech fluency (whether a person can speak easily or with a lot of effort), language comprehension (whether the person has a good or poor grasp of written or spoken words) and the ability to repeat words and phrases.

About 2 million people in the U.S. currently have aphasia, according to the NAA. While the disorder can happen at any age, it's more common in people in middle age and older.

Not surprisingly, aphasia can have “a significant impact on quality of life,” says Brello. “It can limit the ability to socialize with family, friends, work and participate in life activities. Additionally, persons living with aphasia are more likely to experience social isolation, which can lead to depression and reduced life satisfaction.”

What causes it?

Aphasia is typically caused by an acquired brain injury, such as a stroke, head trauma, tumor or neurodegenerative disease. The injury can damage “regions of the brain involved in language processing,” which brings on the condition, Dr. Jagan Pillai of Cleveland Clinic’s Center for Brain Health tells Yahoo Life.

Brello notes that language difficulty resulting from degenerative brain disease is called primary progressive aphasia, “which is a type of dementia,” she says.

With aphasia, there are some telltale signs to look out for, which include “difficulty speaking fluently, difficulty understanding spoken language or difficulty with writing or comprehending reading,” says Pillai.

Aphasia from an acquired brain injury is typically diagnosed by a speech-language pathologist or physician, points out Brello. “Anyone who is experiencing changes in their ability to use language without an acute brain injury should talk with their primary care provider,” she says.

How is aphasia treated?

There is no cure for aphasia. But there are treatment options depending on the cause, notes Pillai. For example, if the condition is caused by a tumor, treatment would likely include removal of the tumor, “whereas for other causes of aphasia, including strokes or neurodegenerative diseases, speech and language therapy exercises [with a speech-language pathologist] can help overcome some difficulties,” he says.

Because aphasia can be overwhelming and isolating, some programs also offer supportive counseling, notes Brello, “to help our group participants with emotional wellness and case management needs.”

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