TRACK-TBI Longitudinal (TRACK-TBI LONG) officially launched in May 2019, supported by funding through a competitive grant from the National Football League Scientific Advisory Board. TRACK-TBI LONG will further advance our understanding of TBI’s natural history by extending follow-up of the original TRACK-TBI cohort by two additional years. This follow-up effort to the TRACK-TBI study aims to collect longer term data on the outcomes of those original TRACK-TBI participants who experienced a brain injury. Over the past year, clinical sites have been re-contacting all TRACK-TBI participants (enrolled from February 2014-August 2018) to gather additional data on participants who are two or more years out from their date of injury. With the TRACK-TBI LONG protocol now in place, sites have completed over 1,000 LONG follow ups. Of these, and additional 190 participants have been followed up at a second time point.  These follow-up phone calls ] include surveys and questions that are very similar to what is asked during the current TRACK-TBI 3-month phone call with some small modifications.