Casey Kasem Dead -- Radio Legend Dies at 82 After Battling Parkinson's Disease

Casey Kasem -- the original voice of the American Top 40 countdown -- died Sunday morning ... TMZ has confirmed.

His daughter Kerri said on Facebook this morning ... her dad was surrounded by family and friends. adding, "Even though we know he is in a better place and no longer suffering, we are heartbroken."

Casey was suffering from advanced Parkinson's Disease and dementia. His wife Jean Kasem moved him to a convalescent home in Santa Monica a few months ago.

Kasem founded the "AT 40" radio franchise back in 1970 ... and famously hosted the wildly popular show until 2004. He went on to do several spinoff countdown shows until he retired from radio in 2009.

He was also very famous for voicing cartoon voices like Shaggy from "Scooby-Doo" ... and Robin on "Super Friends." He was inducted into the National Association of Broadcasters Hall of Fame in 1985.

Casey's illness was marked by a bitter war between Jean and Casey's three children from his previous marriage. The kids claimed Jean blocked them from seeing Casey for several months.

Earlier in the week Kerri took her dad off of all life support including nutrition.

Casey was 82.