Concussions early in life linked to cognitive decline later

A study of twins found that having a concussion early in life is associated with lower scores on tests of thinking and memory abilities decades later, as well as a faster drop in those scores than twins who did not have a concussion or traumatic brain injury (TBI).

The study was published in the American Academy of Neurology's medical publication.

“These findings indicate that even people with traumatic brain injuries in earlier life who appear to have fully recovered from them may still be at increased risk of cognitive problems and dementia later in life,” said study author Marianne Chanti-Ketterl, PhD, MSPH, of Duke University in Durham, North Carolina. “Among identical twins, who share the same genes and many of the same exposures early in life, we found that the twin who had a concussion had lower test scores and faster decline than their twin who had never had a concussion.”

The research included 8,662 World War II veterans. The participants took a thinking skills exam at the start of the study when they were an average of 67 years old, and then again up to three times during the next 12 years. The test has a possible score range of 0 to 50. At the start of the trial, the average score for all participants was 32.5 points.

A total of 25 per cent of the individuals had previously suffered a concussion.

Twins who had a concussion were more likely to have poorer test scores at age 70, particularly if they had a concussion in which they lost consciousness or were older than 24 at the time of their concussion.

Twins with traumatic brain injury with loss of consciousness, more than one traumatic brain injury, and injuries sustained after the age of 24 were more likely to experience faster cognitive decline than those with no history of traumatic brain injury.

A twin who suffered a traumatic brain injury after the age of 24 scored 0.59 point lower at 70 than his sibling who did not suffer a traumatic brain injury, and his cognitive skills dropped faster, by 0.05 point each year.

Other characteristics that could impair thinking skills, such as high blood pressure, alcohol usage, smoking status, and education, were included in these findings.

“Although these effect sizes are modest, the contribution of TBI on late life cognition, in addition to numerous other factors with a detrimental effect on cognition, may be enough to trigger an evaluation for cognitive impairment,” Chanti-Ketterl said.

“With the trend we are seeing with increased emergency room visits due to sports or recreation activity injuries, combined with the estimated half million members of the military who suffered a TBI between 2000 and 2020, the potential long-term impact of TBI cannot be overlooked.

These results may help us identify people who may benefit from early interventions that may slow cognitive decline or potentially delay or prevent dementia.”