I heard it from Doug Limerick on the same station where I can hear recordings of her singing.
But if you want to read
http://www.usatoday.com/story/life/music/2013/08/23/linda-ronstadt-parkinsons-disease/2694053
But if you want to read
http://www.usatoday.com/story/life/music/2013/08/23/linda-ronstadt-parkinsons-disease/2694053