Some people have been known to make the statement that there is no such thing as a mild traumatic brain injury (TBI) or that there is nothing “mild” about a mild TBI. Such statements are meant to convey that if patients experience symptoms after a mild TBI that are perceived as moderate or severe, then the injury should not be described as mild. However, such statements are based more on emotions, subjective perceptions, and patient advocacy as opposed to scientific facts, confusing acute injury characteristics with symptom perception and outcome.

It is a scientific fact that all injuries occur on a continuum. For example, consider cutting your skin. You can have a mild cut that does not bleed (e.g., a paper cut), a moderate cut that bleeds somewhat, or a severe laceration that requires stitches and staples to close the wound. An objective observer would be able to examine these wounds and label them as mild, moderate, and severe. Now let us assume that the person who experiences a paper cut experiences considerable and distressing burning pain afterwards. After all, everyone has different pain severity thresholds and we have all had painful paper cuts. However, the subjective experience of a symptom after an injury does not alter the severity of the actual injury. As such, the person who experiences moderate to severe pain after a paper cut still experienced a mild injury. The injury is mild relative to a bleeding cut or laceration that requires sutures and staples. In a similar manner, a bone fracture can be mild (e.g., hairline fracture), moderate (e.g., clean break), or severe (e.g., pulverized into many tiny pieces). We do not refer to hairline fractures as severe bone breaks because the pain was more than mild.

Brain injury is no different. That is, despite the fact that patients may report severe symptoms after a mild TBI, it does not change the fact that the injury itself was mild. Acute TBI severity is typically based on several factors. One factor is the score on the Glasgow Coma Scale (Teasdale & Jennett, 1974) which assesses level of consciousness. The scale ranges from 3 to 15 points and provides a way to rate patients on their eye movements, motor responses, and verbal responses. The TBI classification scheme based on the GCS is as follows: 13-15 (mild), 9-12 (moderate), and 3-8 (severe). The time it takes someone to form clear and consistent memories after a TBI (known as post-traumatic amnesia [PTA] length) is another marker of injury severity. Different classification schemes have been used in the literature for PTA length, but to illustrate the continuum concept, one example would be: less than 24 hours (mild), 1-7 days (moderate), more than 7 days (severe). Another common TBI severity marker is length of loss of consciousness (LOC). Again, various criteria exist but one example would be: <20 minutes (mild), 20 minutes to 36 hours (moderate), more than 36 hours (severe).