It has been long recognized that a biomarker to detect traumatic brain injury (TBI) would be very useful (see: NFL Physician Says Diagnosis of "Chronic Traumatic Encephalopathy" Lacks Validity; Pro Football Team Experiments with Cone Beam CT Imaging). Current diagnostic methods include the Glasgow coma scale and imaging (see: Traumatic brain injury). Ideally, a biomarker could be made available as a kit or running on a point-of-care device (POCT) to increase the speed of diagnosis. I have generally refrained from discussing news about proposed new biomarkers because most of them don't usually pan out. However, I am making an exception with regard to a recent article about a possible new test for TBI (see: New Blood Test May Detect Traumatic Brain Injury). Below is an excerpt from it:
A new quick blood test may be able to diagnose traumatic brain injury (TBI) and even determine its severity....The test could help determine the best type of treatment for each TBI patient....Until now, most doctors have relied on CT scans and patients’ symptoms to determine whether to send them home and have them resume their usual activities or take extra precautions. However, CT scans can only detect bleeding in the brain, not damage to brain cells, which can occur without bleeding....[R]esearchers wanted to know if a blood test could better predict which patients would have ongoing brain injury-related problems. So they measured the levels of three proteins that they suspected play a role in brain cell activity in more than 300 patients with a TBI and 150 patients without brain injuries. Then, they followed those with a TBI for the next six months.The found that levels of one particular protein, called brain-derived neurotrophic factor (BDNF), taken within 24 hours of someone’s head injury, could predict the severity of a TBI and how a patient would fare.
While healthy people averaged 60 nanograms per milliliter (ml) of BDNF in their blood, patients with brain injuries had less than one-third of that amount, averaging less than 20 nanograms per ml. Those with the most severe TBIs had even lower levels, around 4 nanograms per ml. Furthermore, patients with high levels of BDNF had mostly recovered from their injuries six months later. But in patients with the lowest levels of BDNF, symptoms still lingered at follow-up. The findings strongly suggest that a test for BDNF levels, administered in the emergency room, could help stratify patients.....More research is needed to determine why, at a molecular level, brain injuries decrease levels of BDNF in the blood and whether things known to increase BDNF levels ...could help treat TBIs....[The lead author] also wants to know whether changes in BDNF levels over time can be a proxy for recovery and if they could be used to "gauge the effectiveness of a particular treatment.
The politics and financial implications of a biomarker for TBI are fascinating. Let's say, for example, that BDNF proves to be an accurate predictor of acute TBI. Let's further hypothesize that the BDNF being measured decreases rapidly but transiently in most football players who are in major collisions, which is to say all NFL linemen during the course of a game. One could predict that team owners would probably object to any large-scale testing of their players because such testing could mean that the majority of them could be benched during most games. The owners could respond that one or two transient decreases of BDNF are irrelevant because the levels quickly return to normal and do not serve as a marker for an eventual chronic condition. Obviously, questions like these would need to be explored in future clinical studies.
As noted above, the availability of a biomarker for TBI also raises the feasibility that it could be used to "gauge the effectiveness of a particular treatment." This reminds me of the search for an accurate biomarker for Alzheimer's disease (see: Biomarkers could predict Alzheimer's before it starts). Clinical trials for drugs to treat the disease would be made much easier if subjects could be enrolled on the basis of a lab test rather than the more complex, and perhaps more subjective, methods being used today. Needless to say, some relatives of patients with the disease would appreciate early diagnosis, particularly if a drug was available for treatment.