There is certainly a lot of interest in concussion these days between big screen movies, football, and other sports-related injuries. Concussion, traumatic brain injury (TBI), and mild traumatic brain injury (mTBI) are often used interchangeably. Though mTBI is NOT the first thing we think about in a low-speed motor vehicle collision (MVC), it does happen. So how often do MVC-related TBIs occur, how does one know they have it, and is it usually permanent or long lasting?
Here are some interesting statistics: 1) The incidence rate of fatal and hospitalized TBI in 1994 was estimated to be 91/100,000 (~1%); 2) Each year in the United States, for every person who dies from a brain injury, five are admitted to hospitals and an additional 26 seek treatment for TBI; 3) About 80% of TBIs are considered mild (mTBI); 4) Many mTBIs result from MVCs, but little is known or reported about the crash characteristics. 5) The majority (about 80%) of mTBI improve within three months, while 20% have symptoms for more than six months that can include memory issues, depression, and cognitive difficulty (formulating thought and staying on task). Long-term, unresolved TBI is often referred to as “post-concussive syndrome.”
In one study, researchers followed car crash victims who were admitted into the hospital and found 37.7% were diagnosed with TBI, of which the majority (79%) were defined as minor by a tool called Maximum Abbreviated Injury Scale (MAIS) with a score of one or two (out of a possible six) for head injuries. In contrast to more severe TBIs, mild TBIs occur more often in women, younger drivers, and those who were wearing seatbelts at the time of the crash. Mild TBI is also more prevalent in frontal vs. lateral (“T-bone”) crashes.
As stated previously, we don’t think about our brains being injured in a car crash as much as we do other areas of our body that may be injured—like the neck. In fact, MOST patients only talk about their pain, and their doctor of chiropractic has to specifically ask them about their brain-related symptoms.
How do you know if you have mTBI? An instrument called the Traumatic Brain Injury Questionnaire can be helpful as a screen and can be repeated to monitor improvement. Why does mTBI persist in the “unlucky” 20%? Advanced imaging has come a long way in helping show nerve damage associated with TBI such as DTI (diffuse tensor imaging), but it’s not quite yet readily available. Functional MRI (fMRI) and a type of PET scanning (FDG-PET) help as well, but brain profusion SPECT, which measures the blood flow within the brain and activity patterns at this time, seems the most sensitive.