Not All Traumatic Brain Injuries Are the Same
Mild, moderate, severe, and complicated mild. TBI severity classification is evolving. The new CBI-M framework aims to better reflect real outcomes.
By Attorney Dan D'Angelo
Trial Lawyer · Brain Injury Advocate · Avid Cyclist

Every brain injury is different, and outcomes 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 responsible for controlling different human functions, behavior, and emotions. Depending on location of the brain injury, a person may have different types of impairments.
The severity classification of traumatic brain injury (TBI) lies on a spectrum that falls into three general categories: (1) Mild; (2) Moderate; and (3) Severe. There is no uniform definition. TBI severity classification 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 there is a range. 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. 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.
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.
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. 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 at Bike Brain Law to working with expert doctors in the field of TBI and staying knowledgeable about the latest brain injury science to protect our client’s rights.
Frequently Asked Questions
What are the three severity levels of traumatic brain injury?
Mild, moderate, and severe — based on duration of loss of consciousness, length of post-injury amnesia, Glasgow Coma Scale score, and whether imaging shows abnormalities. Mild is 0–30 minutes of unconsciousness; severe is more than 24 hours.
Is a concussion the same thing as a mild TBI?
Generally, yes — the terms are used interchangeably. Some professional organizations consider concussion the mildest end of the mild TBI range, which also includes sports-related concussion and complicated mild TBI. A concussion is a brain injury and can have serious consequences. If your injury was dismissed as "just a concussion," call me.
Can a "mild" TBI or concussion really change your life?
Absolutely. "Mild" describes the initial severity indicators — not the consequences. A mild TBI can cause debilitating, permanent problems with work, relationships, and daily life. Never let the word "mild" minimize what you're going through.
Have a question about your case?
Attorney Dan D'Angelo offers free consultations for brain injury and cycling accident victims throughout Colorado.
About the Author
Attorney Dan D'Angelo
Trial Lawyer · Brain Injury Advocate · Avid Cyclist
Attorney Dan D'Angelo founded D'Angelo Law Office, P.C. in 2009 and Bike Brain Law to focus exclusively on traumatic brain injury and cycling injury cases in Colorado. An avid cyclist himself, Dan combines deep TBI science knowledge with hands-on cycling experience to build winning cases against insurance companies and corporations that put profits over safety.
- Practicing Colorado personal injury attorney since 2009
- Focused practice in TBI and bicycle injury litigation
- Multi-million dollar settlements and verdicts for injury victims
- Avid road and commuter cyclist
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