The family of actor Bruce Willis announced Wednesday he is stepping away from acting after being diagnosed with a neurological disorder called aphasia.

Northwell neurologist Dr. Shayna Sanguinetti says there is no specific cure for aphasia, which affects speech and comprehension.

"Ability to talk and to understand when they're spoken to," Sanguinetti says. "And it can also affect their ability to write and to read."

Sanguinetti says there are two types of aphasia. One affects a person's ability to talk, and the other affect's a person's ability to understand and for others to understand them.

"They can present something called 'word salad,' where they're producing random words and sentences that seem like normal sentences and it seems like they are responding appropriately," Sanguinetti says. "But, when you ask them certain questions, they're really not responding whatsoever."

Willis' family did not say what type of aphasia the actor has, but say they want to "bring his fans in because we know how much he means to you, as you do to him."

There is no cure for aphasia, but doctors say speech therapy does help some people recover a lot of their language function