March 9, 2023
Former professional football players’ cognitive performance decades after retirement was associated with retrospectively reported concussion symptoms but not concussion diagnosis or length of playing career, according to new research.
“It is well-established that in the hours and days after a concussion, people experience some cognitive impairment. However, when you look decades out, the data on the long-term impact have been mixed,” Laura T. Germine, PhD, director of the Laboratory for Brain and Cognitive Health Technology at McLean Hospital in Belmont, Massachusetts, and associate professor of psychiatry at Harvard Medical School, said in a related press release. “These new findings from the largest study of its kind show that professional football players can still experience cognitive difficulties associated with head injuries decades after they have retired from the sport.”
In a cross-sectional study published in the Archives of Clinical Neuropsychology, Germine and colleagues used data from 3,975 former National Football League players who completed a 76-item health questionnaire and responded to at least six of the 10 questions on concussion signs and symptoms from 2015 to 2019. The researchers identified a subset of 353 participants (median age, 54.3 years) who later remotely completed eight cognitive tests on a laptop or computer, which were taken an average of 29.2 years after the players’ final season of professional play.
Players’ cognitive performance
Compared with players who did not complete cognitive tests, those who did were older, less racially diverse, less likely to report cognition-related challenges and less likely to report symptoms of depression and anxiety. Cognition-related challenges, depression and anxiety were associated with worse overall cognitive performance and more retrospectively reported career-related concussion symptoms.
Adjusting for age, cognitive performance among retired players was associated with reported concussion symptoms (partial correlation [rp] = –0.19; 95% CI, –0.09 to –0.29). Players who reported concussion symptoms specifically did worse on the Digit Symbol Matching test assessing processing speed, the Visual Paired Associates test assessing episodic memory and the vocabulary test.
Notably, overall cognitive performance was not associated with whether players reported any diagnosis of concussion, self-reported number of diagnosed concussions, duration of play in the NFL or age when first exposed to football.
Comparisons with nonplayers
Researchers also compared players’ cognitive performance with that of 5,086 men who did not play in the NFL and completed at least one of the eight cognitive tests.
Compared with nonplayers, former players had worse cognitive performance on the Digit Symbol Matching test (rp = –0.16; 95% CI, –0.2 to –0.13), the Visual Paired Associates test (rp = –0.13; 95% CI, –0.19 to –0.06), the Verbal Paired Associates test assessing episodic memory (rp = –0.18; 95% CI, –0.25 to –0.12) and the Trails A (rp = –0.19; 95% CI, –0.27 to –0.11) and Trails B (rp = –0.13; 95% CI, –0.21 to –0.04) tests assessing processing speed.
“Former players can support their cognitive health as they age by taking proactive steps and continuing to consult with their providers and educate themselves on symptoms of head injury,” Ross D. Zafonte, DO, principal investigator of the Football Players Health Study at Harvard University, said in the release. “For researchers and providers, these findings support efforts to develop ways to enhance diagnosis and define long-term sequalae of concussion.”