The DIAGNOSE-CTE Research Project

Inclusion Criteria: Former NFL Players: * English as primary language * No MRI or Lumbar Puncture (LP) contraindications * Have played ≥12 years of organized football (including =\>3 in college and =\>3 seasons in the NFL) * Must have played one of following positions offensive lineman, defensive lineman, linebacker, tight end, wide receiver, running back, or defensive back. * Agree to provide name and contact information of a study partner who will complete questionnaires regarding subject's mood, behavior, thinking and cognitive function should the subject enroll in the study. Former Collegiate Football Players * English as primary language * No MRI or Lumbar Puncture (LP) contraindications * Must have played =\>6 years of organized football (with =\> 3 years at the college level, but no organized football or other contact sport following college.) * Must have played one of following positions offensive lineman, defensive lineman, linebacker, tight end, wide receiver, running back, or defensive back. * No military service * Agree to provide name and contact information of a study partner who will complete questionnaires regarding subject's mood, behavior, thinking and cognitive function should the subject enroll in the study. Control Group * English as primary language * No MRI or Lumbar Puncture (LP) contraindications * No history of organized contact sports or known traumatic brain injury (TBI) and/or moderate/severe concussions * No history of participation in any …