Predicting Long Term Cognitive Outcomes After Concussion

Researchers utilized cognitive reserve to predict long-term cognitive outcomes.

Researchers claim a new formula accounting for concussion history, cognitive abilities, and other data can predict cognitive outcomes in retired professional football players.

The study, led by Mathew J. Wright, PhD, of the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center and UCLA School of Medicine, was published in the Journal of Clinical and Experimental Neuropsychology.

The researchers focused on cognitive reserve, which describes the brain’s ability to resist injury, both behaviorally and histologically, to help estimate cognitive outcomes in players who had suffered concussions throughout their careers.

The study included 40 retired professional football players who played at least 1 year in the NFL and who completed the CSRA General Health Questionnaire, the Short Form 36 with Mental Component Score of <53, and the International Index of Erectile Function.

To assess cognitive abilities, participants completed the American National Adult Reading Test, the California Verbal Learning Test-Second Edition, the Rey-Osterrieth Complex Figure Test, the Symbol Digit Modalities Test, and parts A and B of the Trail Making Test. Data on demographics, concussion history, game play, steroid use, mood, and obesity were also collected.

Participants displayed deficits in attention and processing speed, verbal and nonverbal memory, and executive ability, with a number of participants showing deficits in 2 or more domains. Notably, concussion frequency did not predict global cognitive ability; however the inclusion of cognitive reserve enhanced the ability of the index to predict global cognition.

Using linear regression, the researchers found that the Cognitive Outcome from Sports Concussion Index (COSCI) significantly predicted global cognition β = 0.56, t(39) = 4.17, P < .001), accounting for 31% of the variance (R2 = .31, F(1, 39) = 17.38, P < .001), and it also predicted the number of cognitive domains with 1 or more deficit scores s [Heaton system: β = –0.39, t(39) = –2.57, P = .014, R2 = .15, F(1, 39) = 6.63, P = .014; Wechsler system: β = – 0.53, t(39)= –3.82, P < .001, R2 = .28, F(1, 39) = 14.60, P < .001].

“We also found that post-traumatic amnesia after a concussion was a more significant predictor of later cognitive deficits than the loss of consciousness,” said Dr Wright. “While further study is needed, our findings open the door to the possibility that professional football could use individual indices to predict the potential for long-term cognitive losses in determining when, or if, a player should return to the field after suffering a concussion.”


Wright MJ, Woo E, Birath JB, et al. An index predictive of cognitive outcome in retired professional American Football players with a history of sports concussion. J Clin Exp Neuropsychol. 2016; doi: 10.1080/13803395.2016.1139057.