Not all traumatic brain injuries are the same.

Every brain injury is different, and results vary from person to person. This is largely because every person is different with their own unique genetics, demographics, and medical history. There are 14 different functional areas of the brain are responsible for controlling different human functions, behavior, and emotions. There is also the left and right hemispheres of the brain that are associated with different characteristics. The brain’s right side is generally the creative side while the left side is analytical side. Depending on location of the brain injury, a person will have different impairments.

The classification of TBI severity lies on a spectrum that falls into three general categories or classifications: (1) Mild; (2) Moderate; and (3) Severe. There is no uniform definition. While multiple professional organizations use different and sometimes conflicting criteria, a TBI generally depends on duration of loss of consciousness, length of post-injury amnesia, Glasgow Coma Scale score, or presence of intracranial abnormality. Within each category exists a range. For example, loss of consciousness for the mild category is 0 to 30 minutes, the moderate category greater than 30 minutes up to 24 hours, and the severe category is greater than 24 hours.

The term “Concussion” is generally used interchangeably with a mild TBI. However, some professional organizations consider a concussion to be a subset of mild TBI on the mildest end of mild TBIs. In the past, there were commonly three grades of concussion (Grade I, II, and III). While this seems to have lost favor there is still a range of mild traumatic brain injuries, which includes concussion, sports-related concussion, mild TBI, and complicated mild TBI. A complicated mild TBI is if all other indicators fall in the mild category but there is positive radiology imaging like a CT scan. Some organizations suggest using a modifier “mild TBI with neuroimaging evidence of structural intracranial injury.” To further expand the spectrum of mild TBIs, the Department of Veterans Affairs/DoD allows a mild TBI with positive imaging findings to be labeled a moderate TBI.

There are shortcomings to this grading system because it does not consider other factors relevant to patient outcome. As a result, there is a strong desire in the medical and scientific communities to move away from the current model of mild, moderate, and severe. In 2025, a new TBI classification framework called CBI-M was announced and is starting trials in trauma centers. This proposed new model will use clinical, biomarker blood tests, imaging, and modifiers based on the patient’s individual factors like existing medical conditions, environmental factors, and how the injury occurred. It’s unclear what labels this new CBI-M framework may assign for severity as it will likely go through further refinement and validation.

The desire to move away from these simple labels recognizes that the current severity ratings are not necessarily an accurate reflection of the severity of the effects a brain injury has on a person’s functioning or the outcome for a person. Mild doesn’t mean the consequences are mild. Instead, a mild TBI can have very serious and debilitating life changing consequences that permanently interfere with work and enjoyment of life.

As the science surrounding TBI continues to evolve, understanding these complexities and changes are important for proper diagnosis, treatment, rehabilitation, and protecting the legal rights of brain injury victims. We are committed to working with expert doctors in the field of TBI and staying informed about the latest brain injury science to protect our client’s rights.

If you have any questions or would like to learn more about our legal services and how our focus in brain injury and bicycle injury cases matters, please get in touch with us via our contact page at Contact Us.

If you found this post helpful, you might also like to explore the other topics listed below and the many other topics in our comprehensive Safety & Prevention Guide, Brain Injury Guide, and Bike Injury Guide.