Age of first exposure to football and later-life cognitive impairment in former NFL players
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Abstract
Objective: To determine the relationship between exposure to repeated head impacts through tackle football prior to age 12, during a key period of brain development, and later-life executive function, memory, and estimated verbal IQ.
Methods: Forty-two former National Football League (NFL) players ages 40–69 from the Diagnosing and Evaluating Traumatic Encephalopathy using Clinical Tests (DETECT) study were matched by age and divided into 2 groups based on their age of first exposure (AFE) to tackle football: AFE <12 and AFE ≥12. Participants completed the Wisconsin Card Sort Test (WCST), Neuropsychological Assessment Battery List Learning test (NAB-LL), and Wide Range Achievement Test, 4th edition (WRAT-4) Reading subtest as part of a larger neuropsychological testing battery.
Results: Former NFL players in the AFE <12 group performed significantly worse than the AFE ≥12 group on all measures of the WCST, NAB-LL, and WRAT-4 Reading tests after controlling for total number of years of football played and age at the time of evaluation, indicating executive dysfunction, memory impairment, and lower estimated verbal IQ.
Conclusions: There is an association between participation in tackle football prior to age 12 and greater later-life cognitive impairment measured using objective neuropsychological tests. These findings suggest that incurring repeated head impacts during a critical neurodevelopmental period may increase the risk of later-life cognitive impairment. If replicated with larger samples and longitudinal designs, these findings may have implications for safety recommendations for youth sports.
GLOSSARY
- %CLR=
- conceptual level responses;
- %E=
- percent errors;
- %PE=
- percent perseverative errors;
- %PR=
- percent perseverative responses;
- AFE=
- age of first exposure;
- CTE=
- chronic traumatic encephalopathy;
- DETECT=
- Diagnosing and Evaluating Traumatic Encephalopathy using Clinical Tests;
- DLPFC=
- dorsolateral prefrontal cortex;
- eVIQ=
- estimated verbal IQ;
- IR=
- Immediate Recall;
- NAB-LL=
- Neuropsychological Assessment Battery List Learning test;
- NFL=
- National Football League;
- RHI=
- repeated head impacts;
- WCST=
- Wisconsin Card Sort Test;
- WRAT-4=
- Wide Range Achievement Test, 4th edition
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Editorial, page 1068
- Received September 5, 2014.
- Accepted in final form November 12, 2014.
- © 2015 American Academy of Neurology
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Letters: Rapid online correspondence
- Author Response
- Robert A. Stern, Boston University School of Medicinebobstern@bu.edu
- Julie M. Stamm, Yorghos Tripodis, Boston
Submitted April 29, 2015 - Cognitive deficits may predate early entry into football
- Glenn J. Larrabee, Neuropsychologist, Independent Practiceglarrabee@aol.com
- Martin L. Rohling, Mobile, Alabama; Laurence M. Binder, Beaverton, Oregon
Submitted March 10, 2015 - Youth football and late-life cognitive impairment
- Jim Andrikopoulos, Neuropsychologist, Independent Practiceneuroclinic@msn.com
- Des Moines, Iowa
Submitted February 26, 2015 - Rebuttal to "Age of first exposure to football and later-life cognitive impairment in former NFL players"
- Joseph C. Maroon, Neurosurgeon, University of Pittsburgh Medical Centermaroonjc@upmc.edu
- Julian Bailes, Pittsburgh, PA; Michael Collins, Pittsburgh, PA; Mark Lovell, Pittsburgh, PA; Christina Mathyssek, Pittsburgh, PA
Submitted February 23, 2015
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