From Acute Trauma to Lifelong Journey: How Research Redefined Brain Injury as a Chronic, Dynamic Condition

By Flora M. Hammond, MD

For decades, traumatic brain injury (TBI) has been viewed as a discrete medical event marked by an initial period of acute care and rehabilitation followed by a presumed plateau. Clinicians have often believed that once a person’s initial recovery stabilized, the effects of the injury would remain largely unchanged for the rest of their life. However, a growing body of research, anchored by the Traumatic Brain Injury Model Systems (TBIMS) program, has challenged and transformed this outdated assumption.

A Paradigm Shift in Understanding Brain Injury: Longitudinal studies conducted through the TBIMS and other research have revealed that outcomes following TBI are more commonly dynamic than static. Rather than reaching a stable endpoint, many individuals with moderate to severe TBI experience ongoing fluctuations in function, including late-emerging symptoms, deterioration, and even improvements, well beyond the first few years post-injury. This insight has spurred a critical rethinking of TBI as a chronic condition, one that requires long-term support, proactive management, and systems of care that recognize and address changes across the lifespan.

The Role of the TBI Model Systems Program: Establishment in 1987 by the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR), the TBIMS program aims to generate and apply knowledge that supports lifelong health, independence, and participation for people living with TBI. The centerpiece of the TBIMS program is its longitudinal database, which has enrolled more than 22,000 individuals with TBI who received inpatient rehabilitation. Participants are followed for life, with more than 70,000 follow-up interviews conducted to date. Enrollees have been followed as far out as 30 years post-injury, providing an invaluable picture of long-term outcome trajectories. These data have enabled researchers to map patterns of change in function, health, and social participation over time. Group-level trends show early improvements that may plateau and then decline, but individual-level trajectories are highly varied. The TBIMS data have helped us start to understand the relationships of outcomes to various influences, such as pre-injury factors, injury characteristics, aging, comorbidities, environmental context, and access to care.

Redefining TBI as a Chronic Health Condition: Findings from the TBIMS database and other studies have led to recognition that TBI shares many characteristics with other chronic conditions: fluctuating symptoms, the need for long-term care coordination, vulnerability to secondary health complications, and the critical role of self-management and lifestyle management. This perspective has been reinforced by the development of models such as BeHEALTHY, which adapts chronic disease management frameworks to brain injury. It emphasizes person-centered care, active engagement in wellness behaviors, self-management, and integration of community and health system supports. In June 2024, this recognition reached a major policy milestone when the Centers for Medicare and Medicaid Services (CMS) included TBI in its list of chronic conditions eligible for Special Needs Plans, paving the way for more tailored health services and financing structures.

Infrastructure That Enables Innovation: The TBIMS program is uniquely equipped to support this shift in care philosophy. Its infrastructure supports health services research, implementation science, and data harmonization across institutions. Its national network includes 16 civilian sites, VA centers, and longitudinal follow-up hubs. Importantly, the program prioritizes stakeholder engagement through a participatory research model that incorporates the voices of individuals with TBI and their families. This has made TBIMS not only a resource for tracking the long-term course of brain injury, but also a platform for testing interventions, refining outcome measures, and guiding national care standards. The TBIMS has contributed more than 700 peer-reviewed publications and informed clinical guidelines, care models, and public health policy.

Looking Ahead: As recognition of TBI as a chronic condition gains momentum, the work of the TBIMS remains vital. By continuing to track and understand the lifelong course of brain injury, the TBIMS program is helping to ensure that individuals with TBI are not forgotten after initial recovery. Instead, the research of the TBIMS and other sources are informing the creation of medical systems and communities better suited to support individuals with brain injury throughout their journey with the tools, knowledge, and care structures necessary to thrive.