In addition to the short-term side effects associated with mild traumatic brain injury (mTBI), or concussion, mounting evidence suggests that these injuries have longer-term effects that can accelerate cognitive decline. Researchers agree that older individuals are more susceptible to the negative symptoms of concussion because their brains are more vulnerable from the normal aging process. Other studies suggest that people who sustained a concussion at a young age are also at high risk for brain structure decline later in life because older brains cannot adequately compensate for damage sustained years ago. However, researchers have not reached consensus about which of these two groups is at the highest risk for cognitive decline as a result of their injuries.
To address this disagreement, a Canadian research team compared a group of people who sustained concussion in their twenties to a group who sustained concussion in their sixties. The participants underwent a number of brain imaging procedures (such as MRI) to determine total brain volume and the structural integrity of the white matter, an important area of the central nervous system that can deteriorate with age. After analyzing the data, the researchers found that individuals who were concussed in young adulthood showed significantly more white matter abnormalities than the group who sustained concussion later in life.
These results suggest that concussion causes a lifelong cascade of neurodegeneration, posing significant long-term health risks for people who are injured in adolescence or early adulthood. Young athlete populations are at particular risk, and those who are first exposed to contact sports at young ages are at the highest risk for poor neurological outcomes later in life. Because the brain never fully recovers from concussion, there is an urgent need to implement new policies and procedures for preventing TBI in these young, at-risk populations, who are likely to develop significant neurological impairments later in life as a result of injuries sustained in adolescence and early adulthood.
Tremblay S, Desjardins M, Bermudez P, et al. Mild traumatic brain injury: The effect of age at trauma onset on brain structure integrity. NeuroImage: Clinical. (June 2019).