Bruce Willis has a progressive brain condition you may not have heard of

After retiring from acting in March 2022 due to a speaking disorder called aphasia, Bruce Willis, 67, has since been diagnosed with frontotemporal dementia, his family announced Thursday.

After retiring from acting in March 2022 due to a speaking disorder called aphasia, Bruce Willis, 67, has since been diagnosed with frontotemporal dementia, his family announced Thursday.

"Since we announced Bruce's diagnosis of aphasia in spring 2022, Bruce's condition has progressed," the Willis family noted in a statement. "Unfortunately, challenges with communication are just one symptom of the disease Bruce faces. While this is painful, it is a relief to finally have a clear diagnosis."

Frontotemporal dementia, or FTD, is a group of disorders caused by a buildup of tau and other brain cell destroying proteins in the brain's frontal lobes (behind your forehead) or temporal lobes (behind your ears). The condition typically strikes between the ages of 45 and 64, according to Alzheimer's Research U.K..

"The most common dementia for people under 60, FTD can cause challenges in communication, as well as changes to one's behavior, personality, or movement," according to a statement from the Association for Frontotemporal Degeneration.

People with FTD typically live six to eight years with the condition, according to the US National Institute on Aging. Between 10 per cent and 30 per cent of FTD cases are inherited. Other than genetics, there are no other known risk factors, although researchers are investigating what role the thyroid and insulin may play in the onset of the disease.

Because his symptoms began with difficulty speaking, Bruce Willis would be classified as having a type of FTD called primary progressive aphasia, said Dr. Henry Paulson, a professor of neurology and director of the Michigan Alzheimer's Disease Center at the University of Michigan.

"Aphasia really means problems with language, and that can vary from having trouble finding your words to understanding what people say. It can occur because of a tumor on the brain, a stroke or from a progressive neurodegenerative condition," Paulson said.