Actor Bruce Willis has been diagnosed with frontotemporal dementia, which evolved from a previous diagnosis of aphasia.
Frontotemporal dementia can cause challenges with communication, as well as a loss of function in the frontal and temporal lobes of the brain.
There are different types of frontotemporal dementia, including behavioral variant frontotemporal dementia and primary progressive aphasia.
FTD can also disrupt motor function and movement, which can be classified as ALS.
FTD is different from Alzheimer's, as it tends to be diagnosed in individuals between their 40s and 60s, while Alzheimer's is typically diagnosed at a later age.
Doctors use brain imaging technology to diagnose FTD, along with a patient's medical history and symptoms.
About 30% of people with frontotemporal degeneration inherit the disease, and there are no known risk factors.
There are medications available to help relieve symptoms of FTD, but the disease eventually gets worse over time.