Concussion - keeping your head in the game

The prevalence of concussion is hard to know, mainly due to issues in reporting it.  For example, official reports from a Canadian amateur hockey association were between 0.25-0.61 per 1000 player game hours whereas player reports for the same association were much higher at 6.65-8.32 per 1000 player game hours.  Women, may be more susceptible for sustaining a concussion, however, they may just be better at reporting it than their male counterparts.  In a study of American High School Athletes, the majority of concussions resulted from football, followed by girls’ soccer, boys’ soccer and girls’ basketball.

 

A diagnosis of concussion (or mild traumatic brain injury) is often made once a Physician rules out any other serious or severe head injury.  In a concussion, neurological signs and symptoms are impaired, often in the absence of macroscopic neural damage.  As such, MRI's and CT's may be normal.  It is now thought that these signs and symptoms seen with a concussion may be due in part to a metabolic change (energy deficiency) in the brain.  

 

image from: http://hellmanholistichealth.com

image from: http://hellmanholistichealth.com

Once more serious brain injuries are ruled out, it can be challenging to know how to manage a concussion as patients can report a variety of symptoms.  The good news is that the majority of people recover quickly from a concussion and do not have any ongoing symptoms.  However, concussions should be treated seriously.  Recovery time lines differ from person to person and do not correlate to the size of the ‘hit’ or ‘incident’.  For many people however, they are not sure what they should be doing and when they should be doing it; this in part, can lead to prolonged symptoms.

 

Due to recent high profile concussion cases and media attention, research on concussion management is increasing and we have a greater insight into their understanding and management.  In Ontario, they are also trying to pass a Bill to improve the rules of managing athletes with concussion, read about it here.  

 

Did you know:

  • Neuronal injury from concussion is largely beneath the detection threshold of conventional clinical CT or MRI scans.  More MR imaging techniques such as functional MRI, diffusion tensor imaging and MR spectography may be better at detecting functional, structural or perfusion changes
  • Current recommendations suggest an initial short period of rest (24-48 hours) followed by gradual, graded return to light cognitive activities such as school, work and physical exertion.  Prolonged rest can actually increase symptoms
  • Impaired eye movements (saccades, smooth pursuits, convergence) are often present in both concussion and post concussion syndrome
  • Conservative treatment for concussion may involve vestibular, visual and graded physical exertion
  • Baseline testing is recommended prior to the start of the season for anyone involved in contact sports
  • Prior to returning to contact sports, patients should be tested for any deficits in balance, strength, memory, cognition, reaction time or any symptom exacerbation during intense physical exertion

 

image from: http://www.texasredzonereport.com

image from: http://www.texasredzonereport.com

There has been mention in the media about long term affects of repeated concussion, mainly the development of chronic traumatic encephalopathy (CTE).  However, the long term risk of neurodegenerative illnesses following concussion is unknown and further studies need to be done to see if there is a definite causal link between concussions and conditions such as CTE.

 

One of the main issues to be aware of is second impact syndrome.  Second impact syndrome (SIS) is where a person suffers a second concussion injury while not being fully recovered from the first.  Research in animals has shown that it may not be the amount of concussions one sustains that is the issue, rather the frequency (how close together) in which they occur.  Generally, if you are fully recovered from a concussion, a second concussion appears to be no more problematic than the first.  If there are concerns though with multiple concussions, some experts have made recommendations of when to cease sport temporarily or permanently; under 18 yrs, stop for the season if you've had 2 concussions in one season.  Adults, stop for the season if you've had 3 concussions in one season.  Retire permanently if subsequent concussions are happening with less force or taking longer to recover from.

 

At present, the safest and fastest way to return to sport after a concussion is to participate in a short rest period followed by a (supervised) graded return to mental and physical activity.

 

Baseline testing can also be helpful in knowing when a player is safe to return.  It also provides the health care professional or physician with important information.  Baseline testing measures a person pre-concussion (eg at the start of the season) over a variety of physical and cognitive tasks.  If a person is symptom free but the brain has not fully recovered, there is likely to be a discrepancy in their pre/post scores.  At present, the best way we have of deciding if it is safe to return to play is if a person is symptom free and performs the same across all the measures as pre-injury.

 

 

Written by

Roland Fletcher, Registered Physiotherapist

 

References:

1. Echemendia, R.J., Iverson, G.L., McCrea, M., Macciocchi, S.N., Gioia, G.A., Putukian, M. and Comper, P. (2013). Advances in neuropsychological assessment of sport-related concussion. British Journal of Sports Medicine 47(5), pp. 294–298.

2. Heitger, M.H., Jones, R.D., Macleod, A.D., Snell, D.L., Frampton, C.M. and Anderson, T.J. (2009). Impaired eye movements in post-concussion syndrome indicate suboptimal brain function beyond the influence of depression, malingering or intellectual ability. Brain 132(10), pp. 2850–2870.

3. McCrory, P., Meeuwisse, W.H., Aubry, M., Cantu, B., Dvorák, J., Echemendia, R.J., Engebretsen, L., et al. (2013). Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. British Journal of Sports Medicine 47(5), pp. 250–258.

4. Thomas, D.G., Apps, J.N., Hoffmann, R.G., McCrea, M. and Hammeke, T. (2015). Benefits of Strict Rest After Acute Concussion: A Randomized Controlled Trial. Paediatrics 135(2), pp. 213–223.

5. Giza, C. C., & Hovda, D. A. (2014). The New Neurometabolic Cascade of Concussion. Neurosurgery, 75, S24–S33.

6. Williamson, I.J.S. and Goodman, D. (2006). Converging evidence for the under-reporting of concussions in youth ice hockey. British Journal of Sports Medicine; 40:128-132.

7. Daneshvar, D.H, Nowinski C.J. et al (2011). The epidemiology of Sport-Related Concussion.  Clinical Sports Medicine; 30(1), 1-17

8. Concannon, L.G., Kaufman, M.S., Herring, S.A. (2014). The Million Dollar Question: When should an athlete retire after concussion? Current Sports Medicine Reports.

9. Love, S. and Solomon, G.S. (2014). Talking with parents of high school football players about chronic traumatic encephalopathy. DOI:10.1177/0363546514535187

10. Maroon. J.C., Winkelman, R. et al (2015). Chronic Traumatic Encephalopathy in contact cports: A systematic review of all reported pathological cases. PLOS ONE DOI: 10.1371/journal.pone.0117338