Concussion Injuries Can Show Up Decades Later

by Susannah Wollman

Have you ever suffered an injury that gave you a concussion? If so, you’re in good company. The most common form of mild traumatic brain injury, over 42 million people annually sustain a concussion. Much study has been done on the effects of mild TBI and the long-term effects are well documented. Patient studies—especially of athletes and members of the military—show the possible connections to neurodegenerative conditions, such as chronic traumatic encephalopathy and Alzheimer’s disease.

How has research shown long-term effects of concussions?

All my life I’ve heard it said that “children are resilient,” and that they suffer little, if any, long-term complications from falls and blows. But that’s no longer the sentiment, as our aging population shows how a concussion that happened as a child can impact the brain and cognitive health even decades later.

The immediate concerns from a concussion have been drilled into our heads, but we are discovering that much of what we thought we knew is in error and further study brings to light newer information. Headaches, light sensitivity, difficulty concentrating, and trouble processing new information can all last much longer than we thought.

The NIA Intramural Research Program’s^[1] (IRP) researchers, led by members of the Brain Aging and Behavior Section, did a long-term study involving 51 older adult participants who had sustained concussions about 20 years earlier. Tracking MRI and PET brain scan data was compared to results from 150 participants who had never had a brain injury. Neuropsychological tests for both groups were also compared in order to detect any changes in cognitive performance over time.

The imaging from the brains of the concussed participants had noticeably higher levels of white matter damage in their frontal lobes, hippocampus, and temporal lobes at their initial study scan. The interesting thing was that the differences remained in the follow-up visits. In addition, the researchers discovered differences in brain activity, also in their frontal and temporal lobes. Brain tissue loss and atrophy was also detected in their temporal lobes.

Interestingly, despite the evidence of TBI in the smaller group, there did not seem to be a relationship between concussion and cognitive ability as both groups tested about the same. Researchers see this area as a need for further study. Is it evidence that the brain is able to compensate and adapt to damage from decades-earlier concussions? The team of researchers want to find evidence that a resilience factor or a work-around is responsible for the lack of cognitive damage from concussions.

However, those who are 50+ and sustained damage to their brains in much earlier life should be aware that the parts of the brain damaged by concussions (the frontal and temporal lobes) are the same areas in which changes are seen in age-connected problems from Alzheimer’s disease and related dementias.

A warning to athletes

The Mayo Clinic says that if an athlete returns to play too soon following a concussion, there is significant risk of sustaining another. More than just losing time playing, a second concussion before the first one is totally healed can result in fatal brain swelling, or second impact syndrome. Each successive concussion can take longer to heal and is likely to result in permanent brain damage.

“The clinical presentation of concussion varies considerably both between individuals and between injuries in one individual,” write the authors of a report published in the Journal of Athletic Training. “Furthermore, athletes with a significant concussion history or other relevant comorbidity, such as attention-deficit hyperactivity disorder, should be considered for testing on an individual basis.”

Individualized care is necessary and if a concussion is suspected, the patient should be given a neurological examination. Physicians may test vision, hearing, coordination and reflexes as well as cognitive tests (including memory and concentration). Severe headaches, seizures, or repeated vomiting indicate imaging test are needed.

Stay informed.

To learn the latest information about concussion, try Concussion.org online for up to the minute news and research concerning concussion.

FOOTNOTE

^[1] Reference: Beason-Held L, et al. Lasting consequences of concussion on the aging brain: Findings from the Baltimore Longitudinal Study of Aging. NeuroImage. 2020;221:117182. doi: 10.1016/j.neuroimage.2020.117182.