The typical concussion is thought to take between one to two weeks to recover from. At least, that is what doctors and patients alike believed until recently. The latest studies suggest that while concussion symptoms can fade away within the weeks after a brain injury, the damage to the brain may last quite a bit longer.
Now, a new study focused on young hockey players suggests that concussions can cause changes in the brain that are observable up to three months after the injury – long after the symptoms have disappeared.
The study, published in an online issue of the journal Neurology, used brain scans to show how concussions leave a lasting effect on the brain that persists after symptoms fade and the teen athletes were allowed back into competition.
“During the early teen years, the brain is still not fully developed and as it continues to grow and mature, it may be more vulnerable to brain injury,” said study author Ravi S. Menon, Ph.D., of Western University in London, Ontario. “Our findings show the brains of young athletes may need more time to recover, which is important because without full recovery, players may be more susceptible to a second concussion that could cause life-threatening brain swelling and bleeding.”
For the study, the researchers examined male hockey players between the ages of 11 to 14 throughout a six-month hockey season. The players practiced twice a week and played at least one game a week on average. During the season, 17 of the hockey players were diagnosed with a concussion.
All the athletes included in the study took tests assessing their thinking, memory, and balance at the start of the season. They also underwent magnetic resonance imaging (MRI) scans of their brain.
Those who experienced a concussion during the season then retook these assessments and underwent a post-concussion MRI scan. The majority of the concussed athletes (14 players) also had a follow-up assessment including the brain scan three months later.
While the concussed athletes initially showed lower scores on tests of their thinking, memory, and balance, their scores returned to normal fairly quickly. Most achieved normal scores an average of 24 days after their injury, allowing them to be cleared to play.
Despite these test scores, MRI scans immediately following the injury and three months later both showed clear signs of damage to the white matter of the brain, as well as a 10% reduction in molecules associated with metabolism.
The researchers noted that the scans also showed that after three months some areas of the brain had begun trying to create new connections to other regions, possibly trying to offset the brain damage.
“More research with MRI is needed to further evaluate our findings because it is critical to understand how and when the adolescent human brain reacts and recovers from concussion,” Menon said. “Current thinking, memory and balance testing may not be sensitive enough. These players were back on the ice when our study suggests their brains still needed time to heal.”
Findings like these raise questions about how we think about recovery after a brain injury, and whether current return-to-play guidelines are letting athletes back into the game while their brain is still injured and vulnerable.