15-Year Longitudinal Study

Study Overview

Section 721 of the 2007 National Defense Authorization Act required a 15-year longitudinal study on the effects of traumatic brain injury incurred by members of the armed forces serving in Operation Iraqi Freedom or Operation Enduring Freedom. The 15-Year Longitudinal TBI Studies included the:

  • Natural History of TBI study
  • Caregiver and Family Member study
  • Archival studies

The research program also included the Improved Understanding of Medical and Psychological Needs in Veterans and Service Members with Chronic TBI study — or IMAP study.

The following questions describe what the research program set out to answer. Download the 15-Year Studies and IMAP Conclusion Summary fact sheet to see what was discovered.

  • What are the long-term physical and mental health effects of TBI?
  • What are the health care, mental health care, and rehabilitation needs?
  • What is the availability of long-term care and rehabilitation programs within and outside the DOD and VA?
  • What is the effect on family members and caregivers?

This research began in 2010 and a final report to Congress is now available. Progress reports at the three-, seven-, and 11-year marks are also available to view or download. 

Learn more about the research from the following resources.

15-Year Studies Program Structure and Demographics

The downloadable infographics here provide details on the longitudinal studies program structure, methodology, and timeline; and outline the population and demographics of the Natural History Study and the Caregiver and Family Member Study.

15-Year Study Findings

These fact sheets and infographics describe important findings of the research.

Graphic of the downloadable P D F of an infographic describing blood-based biomarkers of T B I. Thumbnail image of the downloadable PDF fact sheet on the Risk Factors for Poor Outcomes After TBI. Thumbnail image of the downloadable PDF fact sheet, the15-Year Studies and IMAP Conclusion Summary.

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Fact Sheet
Feb. 18, 2026

DVBIC-TBICoE 15 Year Studies and IMAP Conclusion Summary

.PDF | 562.26 KB

In 2007, the Secretary of Defense chose TBICoE — then known as the Defense and Veterans Brain Injury Center — to direct research into the long-term effects of TBI among those who served in Operation Iraqi Freedom or Operation Enduring Freedom. See an overview of what we learned from the research.

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