Muhammad Ali's Death: Can Head Injuries Cause Parkinson's?

Boxing champion Muhammad Ali lived with Parkinson's disease for three decades before his death on Friday (June 3) at the age of 74, and many have wondered whether Ali's boxing career caused him to develop the neurological disorder. Although it's likely that frequent head injuries played a role in the boxer's Parkinson's disease, certain genes may have also increased his susceptibility to the disease, experts said. "[It's] likely his repeated head injuries contributed to his Parkinson's disease,"