The Next Big Step – Brain Injury Professionals Make Progress on TBI Reclassification Effort
Categories: Professionals, Research, THE Challenge!
By Lauren Moore, Marketing and Communications Manager, BIAA
The medical community took the next step towards implementing an updated classification system for traumatic brain injury (TBI) last month, as professionals from around the world gathered at the National Institutes of Health in Bethesda, Md., for a two-day TBI classification and nomenclature workshop.
The current TBI classification system, which categorizes patients as having sustained “mild,” “moderate,” or “severe” TBI, has been criticized as outdated, inaccurate, and ineffective for serving patients, clinicians, or payers. Calling this system “unsatisfactory from the vantage point of all constituents,” Dr. Michael McCrea, director of the Center for Neurotrauma Research at the Medical College of Wisconsin, pointed out that no other disease uses such reductionistic language as “mild, moderate, or severe,” and especially not to categorize conditions as complex and heterogeneous as TBI. “What has bothered me for a long time now, is that we’re sitting in this antiquated, embarrassing, unenviable position in brain injury science and medicine,” he told attendees.
Under the guidance of a Steering Committee made up of doctors and researchers in the brain injury field, six working groups featuring clinical experts and stakeholders in the TBI field were developed, with each group focusing on one of six key areas: clinical/symptoms (including Glasgow Coma Scale, or GCS scores); imaging (including CT and MRI); blood-based biomarkers; psychosocial and environmental modifiers; knowledge to practice; and retrospective classification.
Dr. Andrew Maas, steering committee member and emeritus professor of neurosurgery at Antwerp University Hospital in Belgium, said the aspect of the knowledge to practice working group was a unique one. “We can come up with recommendations, we can write a publication about it, we can talk about it at meetings – but that doesn’t mean that the medical community takes it up and implements it,” he explained. Including experts in knowledge transfer and implementation science throughout the process has added value to the entire initiative, he added.
Members from each of these groups converged at the two-day workshop to share their findings and collaborate while seeking public input and feedback from the TBI community and stakeholders, with the goal of informing the development of a more precise and evidence-based classification system. The new system, the steering committee stressed, must be both pragmatic for clinical use while also being adaptable for research applications.
“We want to leave with a work product that can be tested and refined. We want a prototype of a better version, recognizing that it will be imperfect until it is perfectly refined and ultimately validated,” Dr. Kristen Dams-O’Connor, steering committee member and director of the Brain Injury Research Center of Mount Sinai, told attendees during the conference.
Participants came to a general consensus about developing a classification according to a concept referred to as CBI-M – Clinical, Biomarkers, Imaging, and Modifiers. These pillars for the proposed new system are intended to help health care professionals consider multiple factors not only at the time of the injury, but at different points in the recovery process, while also considering pre-injury, psychosocial, and environmental modifiers that can impact a patient’s trajectory.
“We’ve focused primarily on the core objective of severity classification, with the expanded ability to reach a richer and deeper characterization in our patients with traumatic brain injury,” Dr. McCrea said.
Clinical Assessment: The Clinical Assessment building block speaks to the role of clinical assessment on Days 1 through 14. This group recommends that core clinical information be collected and recorded for all patients who present to a hospital with TBI. A research priority here would be to optimize the accuracy and utility of the Glasgow Coma Scale, as well as addressing its ceiling and floor effects.
“We’ve known forever that clinical severity is a critical element in classifying the grade of TBI, but also has enormous prognostic utility,” Dr. McCrea said. “There’s no coincidence that the cornerstone of any classification system is clinical indicators.”
The clinically actionable recommendations must go beyond the conventional GCS classification into three categories, Dr. McCrea explained, to the full spectrum of GCS, specifying the component scores of motor, verbal, and eyes, while noting confounds that could impact the score. He also noted the importance of understanding the dynamic nature of clinical status.
Blood-Based Biomarkers: The Blood-Based Biomarkers pillar focuses on select biomarkers for specific use cases in certain settings at specified time points. In certain cases, including among TBI patients who do not receive a CT scan, certain blood-based biomarkers may suggest clinically important brain injury that may not show positive finding on a CT. There is also the possibility that they can help predict the onset or harbinger of neuroworsening.
Compared to the other pillars outlined, biomarkers are a bit of a “newcomer,” Dr. McCrea said. One of the benefits of using biomarkers to classify or categorize patients is the added sensitivity they offer, particularly among the “mildest of the mild” injuries, such as in patients with a GCS between 13-15 and negative MRI and CT.
Imaging: The Imaging pillar addresses the importance of the role of scans such as CT and MRI in diagnosing and categorizing brain injury. The working group focusing on imaging noted the need to strike a balance between the pragmatic usefulness of CT scans with the increased sensitivity of an MRI.
Dr. McCrea noted the difficulty medical professionals might face when treating patients on the lower limit of detection – those whose CT and MRI scans are negative for TBI.
Modifiers: The final pillar in the proposed new classification framework is focused on a biopsychosocial model – preinjury characteristics of the patient that could affect recovery, such as age or history of prior injuries, psychological factors such as the response to trauma or rehabilitation, and social and environmental factors such as the patient’s social support system, geography, and access to care.
“Recovery after TBI is about damage evident on imaging, but it’s also about who comes to injury. Those premorbid factors or host variables. And ultimately the response to injury and the environment in which it takes place,” Dr. McCrea said.
The steering committee provided an example of how this framework could be applied in a real-world setting, by presenting two hypothetical patients with TBI. Under the current model, Patient A, a 29-year-old female, presents with a mild TBI, while Patient B, a 79-year-old male, presents with severe TBI. Within the new framework using the CBI-M pillars, the presentation would include the patient’s GCS score, detailed information about the patient’s scan results, biomarker levels, and relevant medical history, such as a history of depression or prior brain injury.
Dr. Maas added that although the focus going into the conference was on initial injury classification, one important message that came out of the conference was the need for repeated assessment over time. “Which is completely appropriate – a patient can improve, while some patients might deteriorate,” he explained. “They might have a transition, where an injury that was formerly called mild, transforms to a severe TBI.”
Dr. John Corrigan, professor in the department of physical medicine and rehabilitation at The Ohio State University and national research director for the Brain Injury Association of America, led a working group focused on retrospective identification. “We will always need to identify and characterize injuries that occurred in a person’s past. Self-report and medical record abstraction are invaluable tools for clinical, epidemiological and research applications,” he said.
The steering committee noted that this is an ongoing process, with more work to be done as the community works toward a better classification system. “This is a living initiative,” Dr. McCrea told attendees. “This is not something we put to bed two weeks after this workshop and come back and revisit it again in seven years.”
The next steps toward cementing a better TBI classification system includes refining the CBI-M pillars and finalizing its framework, preparing a consensus document, conducting a pilot test in existing data sets, and developing and executing an implementation plan in partnership with stakeholders.
Recordings of the two-day workshop are available on the NIH website:
Knowledge to Practice Chart
The Knowledge to Practice working group outlined a road map of the three most important components of each of the CBI-M Pillars going forward:
This article originally appeared in Volume 18, Issue 1 of THE Challenge! published in 2024.