Glen Campbell's grim diagnosis puts spotlight on Alzheimer's disease

Glen Campbell performing in Sydney, Australia on Jan. 30, 2008 (Credit: Getty Images) (CBS) Glen Campbell may be an "awesome singer and guitar player," as his wife says, but those talents weren't enough to protect him from Alzheimer's. The 75-year-old country music legend said he is battling the devastating neurological disease - and preparing a farewell tour