CSF-Biomarkers in Olympic
boxing: Diagnosis and effects of repetitive head trauma

S., Brisby H., Theodorsson A., Blennow K., Zetterberg H,, Marcusson J. PLoS ONE.
2012; 7(4): 1-8.
has been shown that there are deleterious acute and long-term effects (e.g.,
chronic traumatic brain injury) in the brain among boxing athletes. Currently,
there are no objective measures sensitive enough to diagnosis a concussion or
monitor the long-term effects from head impacts (e.g., neurofibrillary
amyloid plaques). Therefore the
purpose of this study was to evaluate the relation between cerebral spinal fluid
biomarkers (an objective
measure that marks the state of a biological process) and boxing exposure in
elite Olympic boxers. The study included 30 Olympic boxers with a history of at
least 45 bouts (only 26 boxers had complete data due to drop outs) and 25
healthy family or friend controls (non-boxers) matched on age. All participants
filled out a questionnaire about medical history as well as any current head
and neck signs and symptoms, medication, education, occupation, concussion
history, as well as alcohol and drug usage. In addition the boxers reported data
about their boxing career (e.g., number of knock outs, referee stoppages,
record). With this information a boxing expert with no CSF biomarker knowledge
graded the boxers into 1 of 5 boxing exposure categories, where 1 was a boxer
with low risk to receive a head blow according to their reported skill and a boxing
exposure category 5 was a boxer with the highest risk of receiving a blow to
the head. After that, all of the participants had a neurological examination
(e.g., concussion signs and symptoms, coordination, gait, cranial nerves,
neurological status), magnetic resonance imaging (MRI), neuropsychological
testing (e.g., long and short memory, mental speed, recollection), and finally
a lumbar puncture. Lumbar punctures were collected twice for boxers (within 6
days of a bout and at least 14 days after a bout). The cerebral spinal fluid biomarkers
included S-100b, T-tau, neurofilament
light  (NFL), and glial
fibrillary acidic protein (GFAP). The control
subjects had 1 lumbar puncture. No difference were found between boxers and
controls within their medical and social history. Only 1 boxer had current
concussion signs and symptoms listed on the questionnaire. Both, boxers and
control groups had no symptoms of concussion on their neurological exam, MRI,
or neuropsychological examination. Boxers had significantly elevated concentrations
of GFAP and NFL at both acute and long-term tests compared to controls. T-tau
and S-100b were also significantly elevated in boxers compared to control but
only during the acute test period.

head trauma in boxing may be associated with increased risk of chronic
traumatic brain injury. Analysis of biomarkers can assist in understanding the
pathology associated, at a molecular level, with concussions. Furthermore, some
biomarkers may be sensitive enough to detect subclinical brain responses to
repetitive head impacts and could possibly be used to predict the risk of the
patient having a prolong recovery or long-term effects. In this role,
biomarkers may be able to prevent-long term effects if they can be eventually
used to improve return to play guidelines. This data demonstrates that even
though traditional objective and subjective data showed no concussion, the
boxers had higher concentrations of the NFL, GFAP, S100-b, and T-tau biomarkers
within 6 days of a bout, which indicates axonal and neuronal damage. Furthermore,
the elevated NFL and GFAP, even after at least 14 days of no head impact
exposures, may suggest ongoing degenerative changes. In addition, this suggests
that boxers may need longer time off between bouts. Biomarkers may be used to
evaluate recovery and useful in specific return to play guidelines, however,
lumbar puncture is an evasive procedure. It would be interesting to see if
these biomarkers are also elevated in the blood, which would be much easier to
collect. Do you believe biomarkers would be a good tool in concussion
diagnosis, return to play, and following long term recovery?

by: Jane McDevitt MS, ATC, CSCS
by: Jeffrey Driban

Related Posts:

Neselius, S., Brisby, H., Theodorsson, A., Blennow, K., Zetterberg, H., & Marcusson, J. (2012). CSF-Biomarkers in Olympic Boxing: Diagnosis and Effects of Repetitive Head Trauma PLoS ONE, 7 (4) DOI: 10.1371/journal.pone.0033606