New TBI Classification System Aims to Improve Diagnoses and Treatment

After more than 50 years, the medical community is moving towards a new traumatic brain injury (TBI) classification system. 

Today, a coalition of experts from 14 countries proposed a new way to evaluate TBI patients that is expected to lead to more accurate diagnoses and more appropriate treatment plans. A new TBI classification system, reported by the New York Times and published in Lancet Neurology, expands the assessment beyond immediate clinical symptoms. New assessment criteria includes biomarkers, CT and MRI scans, and additional factors such as preexisting medical conditions, environmental factors, and how the injury occurred.

“This new approach to characterizing traumatic brain injury will advance our ability to understand the initial injury,” said John D. Corrigan, PhD, National Research Director for the Brain Injury Association of America and professor in the Department of Physical Medicine and Rehabilitation at The Ohio State University. “People who have had a traumatic brain injury will welcome our abandonment of the overly simplistic ‘mild, moderate, severe’ because for many that nomenclature mischaracterized the lived experience of these injuries.”

For 51 years, trauma centers have used the Glasgow Coma Scale (GCS) to assess and categorize TBI patients. This TBI classification system categorizes patients as having sustained “mild,” “moderate,” or “severe” TBI, and has been criticized as outdated, inaccurate, and ineffective.

CBI-M: Pillars

The new TBI classification framework, called CBI-M, consists of four pillars: clinical, biomarker, imaging, and modifiers.

Clinical: The clinical pillar retains the GCS score – which evaluates a person’s level of consciousness along with pupil reactivity – as a central element of the assessment. The framework recommends including the scale’s responses to eye, verbal, and motor commands or stimuli, presence of amnesia and symptoms like headache, dizziness, and noise sensitivity.

Biomarker: The biomarker pillar uses biomarkers identified in blood tests to provide objective indicators of tissue damage. Low levels of these biomarkers determine which patients don’t require CT scans, which helps reduce unnecessary radiation exposure and health care costs. Biomarkers can also identify patients to enroll in clinical trials to develop new medications for TBI.

Imaging: CT and MRI imaging are important in identifying blood clots, bleeding, and lesions, particularly in patients with more severe injuries, that can point to present and future symptoms.

Modifiers: The modifiers pillar assess how an injury occurred – for example, if a patient was injured in a fall or sustained a blow to the head. This pillar also includes existing conditions, medications, health care access, prior TBI, substance abuse, and living circumstances.

Addressing a Need

A new TBI classification system has been in the works since 2022, when the National Academies of Sciences, Engineering, and Medicine reported that TBI cases in the United States often fail to meet the needs of individuals, families, and communities. According to that report, high-quality care for TBI requires that it be managed as a condition with both acute and long-term phases; public and professional misunderstandings are widespread with respect to frequency, manifestations, long-term consequences, and proper detection, treatment, and rehabilitation of TBI; and the United States lacks a comprehensive framework for addressing TBI.

Last year, TBI experts from around the world gathered at the National Institutes of Health in Bethesda, Md., for a two-day TBI classification and nomenclature workshop, where the CBI-M concept was first established by working groups of federal partners, TBI experts, scientists, and patients.

CBI-M is being phased in at trauma centers on a trial basis, and will be refined and validated before it is fully implemented.