The actor’s family said he was recently “diagnosed with aphasia, which is impacting his cognitive abilities.”

Bruce Willis’ decision to end his acting career of more than four decades after a recent aphasia diagnosis has put a spotlight on the somewhat rare disorder.

Aphasia describes a neurological condition that affects a person’s ability to communicate verbally or through writing. It affects an estimated 2 million people in the United States, and nearly 180,000 acquire it each year,