Rumer Willis, daughter of Willis and Demi Moore, revealed in an Instagram post that her father’s diagnosis is “impacting his cognitive abilities.” “To Bruce’s amazing supporters, as a family we wanted to share that our beloved Bruce has been experiencing some health issues and has recently been diagnosed with aphasia, which is impacting his cognitive abilities,” Rumer Willis wrote. “As a result of this and with much consideration Bruce is stepping away from the career that has meant so much to him,” she added. “This is a really challenging time for our family and we are so appreciative of your continued love, compassion, and support.” Roughly one million Americans have aphasia, and almost 180,000 people develop the condition each year, according to the National Institutes of Health (NIH). Most often it strikes people who are middle-aged or older. Most often, aphasia happens suddenly after a stroke or a brain injury, according to Mayo Clinic. Sometimes it can also develop over time as a result of a slow-growing brain tumor. Signs and symptoms of aphasia can vary based on what portion of the brain is damaged and the extent of the damage, according to the Cleveland Clinic. It can impact both expressive language, or how easily people can put together words and sentences to communicate with spoken or written words, and receptive language, or how well people understand what they hear or read. Some possible symptoms, according to the Cleveland Clinic, can include:

Putting words in the wrong orderMixing up sounds in words, like saying “wog dalker” for “dog walker”Saying the wrong word, like saying “bird” instead of “dog”Substituting a word that doesn’t make sense, like saying “ball” for “phone”Making up jibberish wordsRepeating the same few words or phrases over and over

When aphasia is suspected, patients typically undergo magnetic resonance imaging (MRI) or computerized tomography (CT) scans to confirm the location and extent of damage in the brain, according to the NIH. Doctors will also do cognitive tests to assess what types of speech and language problems are being caused by the condition. Treatment is usually focused on improving language and communication skills, according to the Cleveland Clinic. Patients may work with a speech-language pathologist on exercises to improve reading, speaking, writing, and comprehension. When this doesn’t succeed, patients may also learn to communicate using other methods, like pointing to cards with words or pictures, using smartphone apps to aid communication or generate speech, or using other types of assistive technology.