A multidimensional approach may deliver more accurate diagnosis, targeted treatment, and comprehensive care for people affected by TBI
Nearly 50 million people suffer traumatic brain injuries every year around the world. Traumatic brain injuries killed approximately 70,000 Americans in 2021 and can cause half a million permanent disabilities each year, according to the Centers for Disease Control and Prevention.
Brain injuries can happen during everyday moments. A football tackle sends a player to the ground. A car crashes on the highway. Someone slips on icy steps. Military explosions and repeated hits to the head also can cause brain damage that lasts a lifetime.
Yet doctors still struggle to judge these injuries correctly, especially in the first critical hours. The current system sorts brain injuries into just three groups: "mild," "moderate," or "severe." These labels often mislead patients and families. People labeled with a "mild" TBI usually struggle to have their long-term symptoms taken seriously by care providers. Meanwhile, people with "severe" brain injuries sometimes recover much better than their first diagnosis suggested.
Better ways to classify injuries could lead to more accurate diagnoses and treatments designed for each patient. Doctors could make smarter decisions about critical care, including whether to remove life support. Even people with injuries labeled "mild" could see better long-term results.
To address these issues, researchers funded by the National Institute of Neurological Disorders and Stroke (NINDS) have created a new classification system that could change how doctors understand brain injuries.
The system, called CBI-M, combines clinical tests, biomarkers, brain scans, and individual factors like the cause of injury and medical history, which may offer a more precise way of characterizing and classifying brain injuries.
The framework rests on four main pillars:
- Clinical Assessment: Doctors will still use the Glasgow Coma Scale (GCS), created in 1974. The GCS scores a patient's pupil reactions, movement, and speech to classify injuries as mild, moderate, or severe. The new framework uses each GCS score, not just the total, to give doctors more detailed information.
- Biomarkers (blood tests): In 2018, the Food and Drug Administration (FDA) approved the first blood test for brain injuries. The test measures two proteins that spike after brain damage. Doctors use these results to decide if patients need CT scans in emergency departments (EDs). Newer devices now make these blood tests easier to run in hospitals and clinics. Blood test results help doctors diagnose patients and plan their care.
- Imaging (brain scans): CT and MRI scans, available in most EDs, can spot subtle brain changes that other tests miss. These scans, combined with clinical exams and blood tests, create more accurate diagnoses. The new framework uses the term "traumatic axonal and/or microvascular injury" instead of older terms. Advanced imaging can now detect tiny areas of damage and small bleeds that doctors previously missed.
- Modifiers (personal factors): This new category considers the whole person, not just the injury. Doctors examine mental health conditions, medical history, how the injury happened, and other details that affect recovery. This gives doctors vital context to understand better what each patient needs.
The CBI-M framework needs more testing in large studies before being widely used in clinical practice. However, it shows promise for more accurate diagnoses, better treatments, more thoughtful decisions about life support, and improved outcomes for all patients, including those with mild injuries.
How Experts Built the New TBI Framework
The new CBI-M framework took shape after three years of global teamwork using a careful process that included experts and people affected by brain injuries.
- 2022: NINDS launched a global effort to create a better way to classify brain injuries. Six teams of TBI experts, people who have lived with TBI, implementation scientists, and other researchers from 14 countries joined the project.
- January 2024: The teams met for a workshop to share existing study results and get feedback from the TBI community. They aimed to build a system more accurate than today's "mild, moderate, severe" labels. The meeting featured the new CBI-M framework and discussed how to use it in hospitals. The workshop focused mainly on the CBI-M framework. The teams also talked about how to use it in hospitals, research papers, and ways to track patients for up to two weeks after injury.
- May 2025: Researchers published the CBI-M classification system in The Lancet Neurology. Six related studies in the Journal of Neurotrauma looked at past patient cases and set future research goals.
How NINDS Advances TBI Research and Management
NINDS leads brain injury research through basic, clinical, and treatment studies. Current NINDS-sponsored studies include:
- A study on how the brain repairs itself after injury
- Ways to improve the diagnosis of chronic traumatic encephalopathy (CTE) and related conditions
- How to develop blood tests that help doctors diagnose brain injuries
- Creating standard ways to collect data for brain injury studies
- Finding ways to detect CTE in living patients instead of only after death
- Understanding how brain injuries increase the risk for Alzheimer's disease and other brain diseases, as presented at the ADRD Summit 2025.
NINDS is committed to building a future where TBI can be diagnosed and treated with the same precision we expect for other serious medical conditions. That’s why NINDS supports and sustains collaborative initiatives that encourage continued strides in robust data collection and validated biomarkers.
The NINDS-funded Transforming Research and Clinical Knowledge in TBI, or TRACK TBI, study follows adults and children with all types of brain injuries. It created a brain injury database and tools to help doctors diagnose injuries more accurately and track patient recovery. Researchers continue following participants to identify risk factors and learn about long-term outcomes.
The Federal Interagency TBI Research (FITBIR) program lets researchers share brain injury data. The Department of Defense, NINDS, NIH, and Veterans Administration run this collaborative platform together.
Moving Toward Precision Medicine
The CBI-M framework helps doctors assess brain injuries within 24 hours of impact. This approach prevents problems instead of just treating them after they develop. By adding biomarkers, imaging, and modifiers into standard clinical exams, doctors can better detect, understand, and treat brain injuries. As the framework improves and becomes more available, it could dramatically improve outcomes for millions of people with brain injuries each year.
Learn more about NINDS brain injury research.