Injury from contact sport has harmful, though temporary effect on memory
November 14, 2017
Science Daily/McMaster University
Neuroscientists studying sports-related head injuries have found that it takes less than a full concussion to cause memory loss, possibly because even mild trauma can interrupt the production of new neurons in a region of the brain responsible for memory.
Though such losses are temporary, the findings raise questions about the long-term effects of repeated injuries and the academic performance of student athletes.
The researchers spent months following dozens of athletes involved in high-contact sports such as rugby and football, and believe that concussions and repetitive impact can interrupt neurogenesis -- or the creation of new neurons -- in the hippocampus, a vulnerable region of the brain critical to memory.
The findings were presented today (Tuesday, November 14th) at the Society for Neuroscience's annual conference, Neuroscience 2017, in Washington D.C.
"Not only are newborn neurons critical for memory, but they are also involved in mood and anxiety," explains Melissa McCradden, a neuroscience postdoctoral fellow at McMaster University who conducted the work. "We believe these results may help explain why so many athletes experience difficulties with mood and anxiety in addition to memory problems."
For the study, researchers administered memory tests and assessed different types of athletes in two blocks over the course of two years. In the first block, they compared athletes who had suffered a concussion, uninjured athletes who played the same sport, same-sport athletes with musculoskeletal injuries, and healthy athletes who acted as a control group.
Concussed athletes performed worse on the memory assessment called a mnemonic similarity test (MST), which evaluates a person's ability to distinguish between images that are new, previously presented, or very similar to images previously presented.
In the second study, rugby players were given the MST before the season started, halfway through the season, and one month after their last game. Scores for injured and uninjured athletes alike dropped midseason, compared to preseason scores, but recovered by the postseason assessment.
Both concussed and non-concussed players showed a significant improvement in their performance on the test after a reprieve from their sport.
For the concussed athletes, this occurred after being medically cleared to return to full practice and competition. For the rugby players, they improved after approximately a month away from the sport.
If neurogenesis is negatively affected by concussion, researchers say, exercise could be an important tool in the recovery process, since it is known to promote the production of neurons. A growing body of new research suggests that gentle exercise which is introduced before a concussed patient is fully symptom free, is beneficial.
"The important message here is that the brain does recover from injury after a period of reprieve," says McCradden. "There is a tremendous potential for the brain to heal itself."
https://www.sciencedaily.com/releases/2017/11/171114104225.htm
Contact in sports may lead to differences in the brains of young, healthy athletes
August 22, 2017
Science Daily/St. Michael's Hospital
People who play contact sports show changes to their brain structure and function, with sports that have greater risk of body contact showing greater effects on the brain, a new study has found.
Researchers at St. Michael's Hospital performed preseason brain scans of 65 varsity athletes -- 23 from collision sports (with routine, purposeful body-to-body contact), 22 from contact sports (where contact is allowed, but is not an integral part of the game) and 20 from non-contact sports.
They found that the athletes in collision and contact sports had differences in brain structure, function and chemical markers typically associated with brain injury, compared to athletes in non-contact sports.
Their findings were published online today in the journal Frontiers of Neurology.
Lead author Dr. Nathan Churchill, a post-doctoral fellow in St. Michael's Neuroscience Research Program, said there was growing concern about how participation in contact sports may affect the brain.
Most of the research in this area has focused on the long-term effects for athletes in collision sports, such as football and ice hockey, where players may be exposed to hundreds of impacts in a single season. Less is known about the consequences of participating in contact sports where body-to-body contact is permitted, but is not purposeful, such as soccer, basketball and field hockey.
This study looked at both men and women from a variety of sports, and found progressive differences between the brains of athletes in non-contact, contact and collision sports.
This included differences in the structure of the brain's white matter -- the fibre tracts that connect different parts of the brain and allow them to communicate with one another. Athletes in sports with higher levels of contact also showed signs of reduced communication between brain areas and decreased activity, particularly within areas involved in vision and motor function, compared to those in non-contact sports, such as volleyball.
However, these differences do not reflect significantly impaired day-to-day functioning, said Dr. Tom Schweizer, head of the Neuroscience Research Program and a co-author of the paper, noting that the athletes in this study did not report significant health problems and were all active varsity athletes.
He said this study fills an important gap in understanding how contact affects healthy brains, as a step toward better understanding why a small number of athletes in contact sports show negative long-term health consequences.
https://www.sciencedaily.com/releases/2017/08/170822092215.htm