Traumatic Brain Injury Assessment Gets an Overhaul

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New framework goes beyond the Glasgow Coma Scale to assess TBI severity

by
Judy George, Deputy Managing Editor, MedPage Today
May 23, 2025 • 3 min read

A newly proposed framework expands acute traumatic brain injury (TBI) assessment beyond the Glasgow Coma Scale (GCS).

The framework has four components known as clinical, biomarker, imaging, and modifier (CBI-M) pillars, reported Geoffrey Manley, MD, PhD, of the University of California San Francisco, and co-authors in a Lancet Neurology policy view paper.

The clinical pillar incorporates GCS scores and pupillary reactivity. The biomarker pillar includes blood measurements of glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase L1 (UCH-L1), or S100 calcium-binding protein B (S100B). The imaging pillar uses CT and MRI to assess intracranial damage, and the modifier pillar assesses factors that may influence clinical presentation and outcomes, like comorbidities or how the trauma occurred.

The proposed tool can lead to better diagnoses and treatment and, in some cases, prevent premature discussions about halting life support, the researchers said.

Since 1974, trauma centers have relied mainly on GCS scores to assess patients based on clinical symptoms, rating TBI severity as mild (13-15 points), moderate (9-12 points), or severe (3-8 points). This helped determine the care patients received but often didn’t tell the whole story, Manley noted.

“There are patients diagnosed with concussion whose symptoms are dismissed and receive no follow-up because it’s ‘only’ concussion, and they go on to live with debilitating symptoms that destroy their quality of life,” he said in a statement. “On the other hand, there are patients that were diagnosed with severe TBI — leading full lives — whose families had to consider removing life-sustaining treatment.”

The clinical pillar of the framework retains the GCS score as a core element. “This pillar should be assessed as first priority in all patients,” said co-author Andrew Maas, MD, PhD, of the Antwerp University Hospital in Belgium. “Research has shown that the elements of this pillar are highly predictive of injury severity and patient outcome.”

The new framework is intended for patients with TBI of all severities (GCS score 3–15). The sequence in which pillars are assessed will depend on the clinical condition of the patient and available resources.

While it’s a substantial advancement, the CBI-M framework is “not yet ideal,” observed Jiyao Jiang, MD, of Shanghai Jiao Tong University in China, and colleagues, in a comment accompanying the paper.

“The biomarker pillar might be applied mainly to the assessment of patients with mild TBI and the sequelae of acute TBI, which has less relevance in guiding acute management for patients with severe TBI, in whom conditions can change rapidly,” Jiang and co-authors wrote.

“Similar to the biomarker pillar, the modifier pillar — an individual’s biopsychosocial characteristics — can be valuable for predicting outcomes in patients with TBI but has minimal effect on decision making, particularly during the acute phase of TBI,” they continued.

The CBI-M framework does not include intracranial pressure, “the most crucial physiological index in moderate-to-severe TBI,” the editorialists added.

“Clinical classification tools need to be operable and follow the principles of simplicity and practicality,” Jiang and co-authors pointed out. “To gain recognition and application in countries around the world, the CBI-M framework requires improvement and practical testing through global multicenter, large-scale, prospective cohort studies.”

In 2022, the National Academies of Science, Engineering, and Medicine called for an updated TBI classification system. The CBI-M framework was developed in response to that recommendation and to changes in the field, Manley and colleagues said.

“We do not present this framework as a finished product,” they emphasized. “The framework will require refinement and validation in large contemporary studies before being considered for implementation into general clinical practice.”

Validation is ongoing, and preliminary results show strong correlations of injury-related components with the CBI-M pillars, they noted.