In this scoping review of military service–related traumatic brain injury (TBI) studies, authors map the progress of TBI research from January 2015 through June 2025 and identify overlaps and gaps in specific areas. They also highlight areas that received the most-focused investment. The results can inform opportunities to better align research efforts and investments and address gaps in TBI knowledge and care for service members and veterans.

A Review of U.S. Military Traumatic Brain Injury Studies

Trends, Gaps, and Opportunities

Emily Hoch, Jose Martinez, Rushil Bakhshi, Maggie Hieber, Aaron Presser, Thomas Tartaglia

ResearchPublished Nov 10, 2025

In this scoping review of military service–related traumatic brain injury (TBI) studies, authors map the progress of TBI research from January 2015 through June 2025 and identify overlaps and gaps in specific areas. They also highlight areas that received the most-focused investment. 

Service-related TBI is a signature wound of war, affecting more than 500,000 service members since 2000, and special operations forces (SOF) are at particularly high risk because of frequent blast exposures and repetitive neurological stresses. Many TBIs go undiagnosed or are mild, yet they often co-occur with such conditions as posttraumatic stress disorder and depression and lead to significant long-term health impacts. Despite substantial federal and private investment, TBI research remains fragmented and siloed, highlighting the need for a comprehensive assessment of research efforts and funding in this critical area.

By highlighting both research achievements and persistent gaps, this study provides a road map for policymakers, funders, and researchers to align priorities to close knowledge gaps. A more coordinated research agenda is essential to advance prevention, diagnosis, treatment, and long-term recovery and ensure comprehensive care and support for all service members and veterans living with TBI.

Key Findings

The type and volume of research on military service–related TBI reveal important gaps

  • There is limited research focused on TBI among SOF, although this population faces a higher risk of blast exposure and TBI.
  • Most TBI research studies are observational and focus on diagnostic methods; far fewer papers focus on interventions or the root causes of blast injuries.
  • Nonhuman research mainly uses murine models, and there are few studies involving larger animals or digital simulations.
  • Most TBI studies examine TBI in the presence of other conditions.
  • Studies on short- and long-term outcomes of TBI focus on different issues.
  • Most studies focus on one stage of TBI care, and few focus on prevention and rehabilitation.

The funding sources and amounts for military service–related TBI research suggest increasing interest in TBI research

  • Since 2015, federal and private sources have invested more than $2.1 billion in TBI research.
  • The U.S. Department of War and the U.S. Department of Health and Human Services are leading research funders.
  • Grant funding peaked in 2022, reflecting a significant increase in investment and interest in TBI research.
  • Philanthropic contributions have steadily increased to nearly $80 million cumulatively, supporting various initiatives within TBI research.

Topics

Document Details

  • Copyright: Invisible Wounds Foundation
  • Publisher: RAND Corporation
  • Availability: Web-Only
  • Year: 2025
  • Pages: 56
  • DOI: https://doi.org/10.7249/RRA4199-1
  • Document Number: RR-A4199-1

Citation

Chicago Manual of Style

Hoch, Emily, Jose Martinez, Rushil Bakhshi, Maggie Hieber, Aaron Presser, and Thomas Tartaglia, A Review of U.S. Military Traumatic Brain Injury Studies: Trends, Gaps, and Opportunities. Santa Monica, CA: RAND Corporation, 2025. https://www.rand.org/pubs/research_reports/RRA4199-1.html.
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This research was funded by the Invisible Wounds Foundation and conducted within the RAND Epstein Family Veterans Policy Research Institute.

This publication is part of the RAND research report series. Research reports present research findings and objective analysis that address the challenges facing the public and private sectors. All RAND research reports undergo rigorous peer review to ensure high standards for research quality and objectivity.

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