Inclusion Criteria:  LONGITUDINAL Telephone Assessment: Participated in TRACK-TBI, At least two years post injury, and Completed at least 1 GOSE during the TRACK-TBI follow-up assessments LONGITUDINAL BIOMARKER In-Person Assessment:  Must complete at least one Longitudinal Telephone Assessment and fall into one of the following groups:  Group 1- Completed TRACK-TBI 6M MRI and are stable or improved with regard to Criteria for Establishing Decline Group 2- Criteria for Establishing Decline met when comparing the Telephone Assessments to the last completed TRACK-TBI assessment Group 3- All TRACK-TBI orthopedic controls  Ability of participant or legally authorized representative to provide informed consent  Exclusion Criteria:  Dementia diagnosed prior to the index TBI