Justin Morneau: Wimp or Victim?

Morneaus Concussion
If you’re  a rabid Twins fan like I am, you’ve probably seen this video many times. Justin Morneau’s slide in an attempt to break up a double play may have been successful, but the blow to his head resulted in a concussion just before the 2010 All Star Break in July. Voted in as the starting first baseman for the AL, he was unable to play in the game. He was unable to play the rest of the season. His level of play significantly decreased throughout the following season, and it was clear he was not the player he was a year before.
Has this concussion become a scapegoat for Morneau’s decline, while other factors are the actual contributors? Many Twins fans have displayed obvious frustration with his inability to play at his all-star capability, and some have questioned whether he is simply using the concussion as an excuse for his shoddy play. Or is it possible the concusion suffered in July 2010 was still affecting him over a year later? I am inclined to think the latter.
Before his famed baseball years, Justin Morneau played youth hockey, and has admitted to having several head injuries during that time. An article we’ve been reviewing in our Neurochemistry class talks about the mechanisms behind concussions. A large mechanical force upon the brain (such as a shortstop’s knee to your head) can cause the rapid release of the excitatory neurotransmitter glutamate. These neurotransmitters can bind to certain receptors in the brain causing potassium ions to leave the cell. In an attempt to alleviate these neurological changes, pumps in the brain work overtime to restore the brain to its normal state. This requires energy, leaving the brain in an energy crisis and causing hyperglycolisis, the break down of glucose to provide energy. Any further injury or mechanism that requires energy during this crisis could cause the brain further injury. However, this period of vulnerability can often be quite short. Pitcher Josh Beckett took a line drive to the head and experienced concussion symptoms the next day, and was cleared to pitch 8 days later. Unlike Morneau, Beckett did not have a rich history of concussions.
Why do the number of concussions have an effect on concussion symptom severity and duration? If they didn’t, Justin Morneau could have been back after a week or two. However, our article explained that repeated brain injury can result in longer lasting symptoms. After the initial period of hyperglycolysis, the brain goes into a reduced state of glucose metabolism to counter this disrepancy between energy supply and demand. The body may not be able to respond correctly to another injury during this time. Additionally, calcium ions can enter the cell and accumulate due to the receptor binding mentioned above. Accumulated calcium can lead to cellular death through various mechanisms. The brain is very vulnerable during this time. It is not necessary to receive another blow in the head for the condition to worsen; simple activity can aggravate the sensitive system. This period of vulnerability becomes longer and longer the more concussions you have, leaving the vulnerability and chance of re-injury higher for much longer. For example, Morneau returning to batting practice or fielding practice can be enough to restart concussion symptoms even without a blow or disturbance of the head.
Tests have been developed to test whether athletes are ready to return to play after a concussion. While the test is more or less a simple test of reaction time and motor ability, slight deviations from the athlete’s baseline (how well they performed on the test when healthy) may result in being held from play longer to ensure full recovery. As recent as September 2011, Morneau still did not pass this test, despite being closer than he has been over the past year. This indicates he is still suffering from some symptoms over 14 months later. Further, steps are being made in the MLB to prevent players from rushing back to play after head injuries. A 7-day disabled list was added this last season so teams could fill a roster spot during the player’s injury, making them less likely to push their athletes into returning before their full recovery.
Though the brain is able to show plasticity and resistance/recovery from injury, it is the most important area of our body to protect. Too much traumatic brain injury can lead to long lasting loss of function and even neurological diseases. It will be interesting to see whether Morneau will ever be able to recover from his latest concussion. How many concussions can you have before your brain simply can’t restore itself to normal function? With Morneau, only time will tell.