In April a Swedish study was released on boxing and biomarkers in the cerebrospinal fluid (CSF); findings were not only somewhat successful for possibly getting a biomarker test, it shed light on the controversial subconcussive blows and cumulative effects as well.
Sanna Neselius, Helena Brisby, Annette Theodorsson, Kaj Blennow, Henrik Zetterberg and Jan Marcusson did perform the largest study of active boxers known, what was less known until this one study is how long and what level the CSF biomarkers are in samples of each boxer. The most curious part of the study is that only ONE of the boxers ever reported symptoms associated with concussion yet the results show increased levels of certain biomarkers in 80% of the boxers that would be indicative of “acute axonal and neuronal damage.”
The studied biomarkers were;
Biomarkers for brain damage include neurofilament light protein (NFL), a marker of subcortical myelinated axons , total tau (T-tau), a marker of cortical axons , , tau phosphorylated at threonine 181 (P-tau181), a marker of tangle pathology , heart-type fatty acid binding protein (H-FABP), a marker of grey matter neurons , glial fibrillary acidic protein (GFAP)  and S-100B as markers of astroglial cells ,  and the 42 amino acid isoform of amyloid β (Aβ1–42), marker of plaque pathology .
Not only were the biomarkers collected in the acute time frame (within 6 days) but also after a period of 14 days, or resting the brain. Interestingly enough even after the resting period boxers continued to have high levels of NFL and T-tau;
Increased CSF levels of T-tau, NFL, GFAP, and S-100B in >80% of the boxers demonstrate that both the acute and the cumulative effect of head trauma in Olympic boxing may induce CSF biomarker changes that suggest minor central nervous injuries. The lack of normalization of NFL and GFAP after the rest period in a subgroup of boxers may indicate ongoing degeneration. The recurrent head trauma in boxing may be associated with increased risk of chronic traumatic brain injury.
What this study tell us in layman’s terms is:
- After boxing there are chemical changes at a level consistent with nerve damage in the brain even WITHOUT symptoms
- After boxing and a 14 day rest period levels of chemical changes in the brain continue to be high enough to be consistent with some sort of damage
- There may be more solid information for an objective type test for traumatic brain injury