Ali's doctor plays down suggestions of boxing link to Parkinson's

Muhammad Ali’s personal doctor has revealed he cannot be sure that boxing contributed to the former heavyweight world champion’s Parkinson’s Disease.

Ali, considered by many to be the greatest boxer of all time, has suffered with the neurological syndrome since the mid-1980s and it has often been presumed that blows to the head during his 21-year professional career were a contributing factor to his condition.