Relationship of collegiate football experience and concussion with hippocampal volume and cognitive outcomes.
OBJECTIVE
Concussion and subconcussive impacts have been associated with short-term disrupted cognitive performance in collegiate athletes, but there are limited data on their long-term neuroanatomic and cognitive consequences.


OBJECTIVE
To assess the relationships of concussion history and years of football experience with hippocampal volume and cognitive performance in collegiate football athletes.


METHODS
Cross-sectional study conducted between June 2011 and August 2013 at a US psychiatric research institute specializing in neuroimaging among collegiate football players with a history of clinician-diagnosed concussion (n = 25), collegiate football players without a history of concussion (n = 25), and non-football-playing, age-, sex-, and education-matched healthy controls (n = 25).


METHODS
History of clinician-diagnosed concussion and years of football experience.


METHODS
High-resolution anatomical magnetic resonance imaging was used to quantify brain volumes. Baseline scores on a computerized concussion-related cognitive battery were used for cognitive assessment in athletes.


RESULTS
Players with and without a history of concussion had smaller hippocampal volumes relative to healthy control participants (with concussion: t48 = 7.58; P < .001; mean difference, 1788 μL; 95% CI, 1317-2258 μL; without concussion: t48 = 4.35; P < .001, mean difference, 1027 μL; 95% CI, 556-1498 μL). Players with a history of concussion had smaller hippocampal volumes than players without concussion (t48 = 3.15; P < .001; mean difference, 761 μL; 95% CI, 280-1242 μL). In both athlete groups, there was a statistically significant inverse relationship between left hippocampal volume and number of years of football played (t46 = -3.62; P < .001; coefficient = -43.54; 95% CI, -67.66 to -19.41). Behavioral testing demonstrated no differences between athletes with and without a concussion history on 5 cognitive measures but did show an inverse correlation between years of playing football and reaction time (ρ42 = -0.43; 95% CI, -0.46 to -0.40; P = .005).


CONCLUSIONS
Among a group of collegiate football athletes, there was a significant inverse relationship of concussion and years of football played with hippocampal volume. Years of football experience also correlated with slower reaction time. Further research is needed to determine the temporal relationships of these findings.
Laureate Institute for Brain Research, Tulsa, Oklahoma.
Rashmi
R
Singh
Laureate Institute for Brain Research, Tulsa, Oklahoma.
Timothy B
TB
Meier
Laureate Institute for Brain Research, Tulsa, Oklahoma2Tandy School of Computer Science, The University of Tulsa, Tulsa, Oklahoma.
Rayus
R
Kuplicki
Laureate Institute for Brain Research, Tulsa, Oklahoma3Faculty of Community Medicine, The University of Tulsa, Tulsa, Oklahoma.
Jonathan
J
Savitz
Laureate Institute for Brain Research, Tulsa, Oklahoma.
Ikuko
I
Mukai
Department of Family Medicine, The University of Oklahoma School of Community Medicine, Tulsa.
LaMont
L
Cavanagh
Department of Family Medicine, The University of Oklahoma School of Community Medicine, Tulsa.
Thomas
T
Allen
Departments of Surgery and Psychiatry, The University of Oklahoma School of Community Medicine, Tulsa6Department of Pharmaceutical Sciences, The University Oklahoma College of Pharmacy, Tulsa7Department of Biochemistry and Microbiology, Oklahoma State Uni.
T Kent
TK
Teague
Department of Athletics, The University of Tulsa, Tulsa, Oklahoma.
Christopher
C
Nerio
Department of Athletics, The University of Tulsa, Tulsa, Oklahoma.
David
D
Polanski
Laureate Institute for Brain Research, Tulsa, Oklahoma3Faculty of Community Medicine, The University of Tulsa, Tulsa, Oklahoma.
Patrick S F
PS
Bellgowan
D056352:Athletes / Q000706:statistics & numerical data; D001924:Brain Concussion / Q000150:complications*; D016022:Case-Control Studies; D003071:Cognition; D003430:Cross-Sectional Studies; D005538:Football / Q000293:injuries*; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011930:Reaction Time; D013334:Students / Q000706:statistics & numerical data; D014495:Universities; D055815:Young Adult