New research has reinforced the direct relationship between repetitive head impacts (RHI), traumatic brain injury (TBI) and neurological dysfunction later in life. While a logical link exists, this most recent study provides insight into not only cognitive challenges, like working memory, processing speed, learning and reaction time, but also the onset of depression as a result of experience with contact sports, physical abuse or military service.
The findings, published in Neurology, were based on the largest population sample to date; 13,323 individuals, aged 40 and over, who participate in the Brain Health Registry (BHR), an internet-based, cognitive assessment system. In addition to a self-reporting questionnaire on RHI/TBI history and a depression rating scale, the participants completed the Cogstate Brief Battery and the Lumos Labs NeuroCognitive Performance Tests (NPT) through an at-home, online environment.
The Boston University Chronic Traumatic Encephalopathy (CTE) Center, the source of several important studies on football and CTE, partnered with the University of California, San Francisco (UCSF) to broaden the control group used to compare brain aging. In 2017, the CTE Center released a significant report that showed widespread CTE among deceased NFL players. And in 2019, they published a study showing that for every year of participation in American football a player’s risk of eventual CTE increased by 30%.
In the current study, the research team analyzed the BHR results to look for any correlation between brain impact or injury earlier in life with neurological issues after the age of 40. First, they found that those adults who had a history of RHI and TBI reported a significantly greater number of depression symptoms than the control group who had no past head injury. Moreover, when compared separately, those with just RHI had a higher incidence of depression years later.
“The findings underscore that repetitive hits to the head, such as those from contact sport participation or physical abuse, might be associated with later-life symptoms of depression. It should be made clear that this association is likely to be dependent on the dose or duration of repetitive head impacts and this information was not available for this study,” said Michael Alosco, PhD, associate professor of neurology and co-director of the BU Alzheimer’s Disease Center Clinical Core.
Participants who had either RHI or TBI at a younger age showed worse performance on some of the Cogstate Brief Battery and Lumos Labs NPT cognitive tests. But those who suffered from both RHI and TBI scored lower on almost all of the tests compared to the control group.
“These findings add to the growing knowledge about the long-term neurological consequences of brain trauma,” said Robert Stern, PhD, professor at the Boston University School of Medicine and director of clinical research at the BU CTE Center. “It should be noted that not all people with a history of repetitive hits to the head will develop later-life problems with cognitive functioning and depression. However, results from this study provide further evidence that exposure to repetitive head impacts, such as through the routine play of tackle football, plays an important role in the development in these later-life cognitive and emotional problems.”
Access to the Brain Health Registry online cognitive testing data was vital for this research, as assembling a population of this size in a lab-visit setting would be impractical.
At-home, secure computerized assessment is becoming even more important to brain research with the limitations of current coronavirus restrictions. Recruitment of study volunteers is made easier with validated systems like the Cogstate Brief Battery.
“The Brain Health Registry is a novel and exciting resource for both the scientific community and the general public,” said Michael Weiner, MD, PI of the Brain Health Registry and professor-in-residence at UCSF. “It allows for large-scale recruitment, screening and study of dementia, and more than 60,000 individuals across the world are enrolled. It offers a way for the general public to track their thinking, memory, mood, and behavior over time, and also serves as a readiness registry for future research and clinical trials of prevention and treatment.”