Brett Favre's Parkinson's diagnosis highlights potential links between collision sports and brain disease, with studies suggesting concussions raise Parkinson's risk by over 55%. Favre, who played 20 NFL seasons, discussed his diagnosis during a welfare scandal hearing, noting his belief in a 'breakthrough concussion drug'. Research indicates football increases Parkinson's risk by 61%, with repetitive head impacts linked to precursors of the disease. Neurologists stress multiple risk factors for Parkinson's, cautioning against immediate links to football injuries.