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 1,800 LONG follow ups. Of these, 594 participants have completed a follow up at a second time point, and 30 at a third time point.