Barker, 99, had never publicly addressed his battle with the disease and it's unclear when he was diagnosed, however, the documents state that it came "years" before his death last month. The longtime animal activist had previously urged fans to go vegetarian in an effort to help prevent the onset of Alzheimer's disease on behalf of PETA in 2013.
Barker died "peacefully" the age of 99 at his Los Angeles home on August 26, a representative confirmed to TMZ at the time.
The television icon was the host of CBS' gameshow The Price Is Right, from its debut in 1972 until his retirement in June 2007, at which point he was succeeded by current host Drew Carey.
"We lost a beloved member of the CBS family today with the passing of Bob Barker," the network said in a statement to TMZ at the time of Barker's death. "During his 35 years as host of The Price Is Right, Bob made countless people’s dreams come true and everyone feel like a winner when they were called to ‘come on down.’ In addition to his legendary 50-year career in broadcasting, Bob will be remembered as a dedicated animal rights activist. Daytime television has lost one of its most iconic stars."