Ozzy Osbourne announced recently he’s been diagnosed with Parkin, a rare form of Parkinson’s Disease which could eventually rob him of his singing voice.

According to the Michael J Fox Foundation for Parkinson’s Research, it is not uncommon for patients to struggle with speaking and swallowing. Parkinson’s affects the way the vocal cords and swallow muscles actually move and causes the voice to get quieter.

Read more about Ozzy’s health struggles here.