There is a condition that stems from too many concussions that has caused some former professional athletes to lose their memory, their independence and in some cases, their lives.

FOX News Radio's Jennifer Keiper reports in the fifth installment of our ten-part series investigating the growing concern about concussions in the sport:

Suffer too many concussions and it could lead to a severe condition called chronic traumatic encephalopathy or CTE. It's a progressive degenerative disease of the brain. Why so many concussions in football?

Dr. Holly Benjamin with the University of Chicago:

(Benjamin) "The number of hits that you get, the severity of the hits that you get, and the location of the hits."

Larry Morris helped the Chicago Bears win the 1963 World Championship:

(Amy Morris) "Remember your friend Jim Orr? Jimmy Orr played for the Colts."

No response.

His wife Amy thinks the dementia is the result of Morris' hard-hitting pigskin days. It started in his 40's:

(Amy Morris) "You know - struggling to remember little things that most people could remember."

Some ex-pro-baller suicides have been connected to CTE. For former Oilers and Dolphins linebacker John Grimsley it was an accidental gunshot wound. However, before that, he had become increasingly forgetful and aggressive.

Boston University neuropathologist Dr. Ann McKee, testifying before Congress, said the protein buildup in Grimsley's brain was so abnormal that it could be seen, without a microscope, all over the brain.

She calls CTE a devastating disorder.

Jennifer Keiper, FOX News Radio.

CLICK HERE for more of the FOX News Radio series "Head Games: The Dark Side of Football".

CLICK HERE to listen to the full FOX News Radio special "Head Games: The Dark Side of Football".