Citation

Wilde EA, Hunter J, Li X, Amador C, Hanten G, Newsome M, Wu T, McCauley SR, Vogt GS, Chu Z, Biekman B, Levin H. J. Neurotrauma 2015; 33(7): 672-680.

Affiliation

Baylor College of Medicine, Cognitive Neuroscience Laboratory , 1709 dryden rd , houston, Texas, United States , 77030 , 7137987566 ; hlevin@bcm.edu.

Copyright

(Copyright © 2015, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2015.4035

PMID

26414735

Abstract

We used magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to evaluate the effects of boxing on brain structure and cognition in 10 boxers (8 retired, 2 active) (mean age=45.7 years, SD=9.71) and nine participants (mean age=43.44, SD=9.11) in non-combative sports. Evans Index (maximum width of the anterior horns of the lateral ventricles/maximal width of the internal diameter of the skull) was significantly larger in the boxers, (F=4.52, p=0.050; Cohen's f=0.531). Word list recall was impaired in the boxers ((F1,14)=10.70, p=0.006, f=0.84)) whereas implicit memory measured by faster reaction time (RT) to a repeating sequence of numbers than to a random sequence was preserved t=2.52, p<0.04. Fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) measured by tractography did not significantly differ between the groups. However, DTI metrics were significantly correlated with declarative memory (e.g., left ventral striatum ADC with delayed recall, r=-0.74, p=0.02) and with RT to the repeating number sequence, (r=0.70, p=0.04) in the boxers. Years of boxing had the most consistent, negative correlations with FA, ranging from -0.65 for the right ventral striatum to -0.92 for the right cerebral peduncle. Years of boxing was negatively related to the number of words consistently recalled over trials (r=-.74, p=0.02), delayed recall (r=-0.83, p=0.003), and serial RT, (r=.66, p=0.05). We conclude that microstructural integrity of white matter tracts is related to declarative memory and response speed in boxers and to the extent of boxing exposure. Implications for chronic traumatic encephalopathy are discussed.

Language: en