Effects
of career duration, concussion history, and playing position on white matter
microstructure and functional neural recruitment in former college and
professional football athletes.  
Clark MD, Varangis EML, Champagne AA, Giovanello KS,
Shi F, Kerr ZY, Smith JK, Guskiewicz KM. 2017. Radiology: ahead of print.
Take Home
Message
: White matter transformations
were found in athletes without any clinical or outward behavioral or cognitive abnormalities.
https://upload.wikimedia.org/wikipedia/commons/8/87/Functional_magnetic_resonance_imaging.jpgAn
increased number of concussive and subconcussive impacts over several years may
be a risk factor for the development of neurodegenerative disease. Neuroimaging
could be used to determine changes later in life. However, there is little
research conducted to determine the effects impact exposure on white matter. Therefore,
the authors collected information from healthy (no cognitive or mood
impairments), former professional (30 athletes) and collegiate (31 athletes) football
players. The professional athletes completed a general health survey between
2001 and 2010, played more than 5 years of professional football, were between
the ages of 55 and 65 years old, and did not play in a kicking position. The
college athletes met similar criteria but played at least 3 years. The retired athletes
completed a neuropsychological assessment [Mini Mental State Examination (MMSE),
Repeatable Battery for the Assessment of Neuropsychological status (RBANS), and Wechsler
Adult Intelligence Scale-third edition (WAIS-III)]. The former athletes also received functional (analysis
of working memory) and diffuse magnetic resonance imaging (MRI) to measure
white matter integrity. Athletes reported their concussion history and the
investigators categorized them as a high frequency group (self-reported 3 or
more concussion) or low frequency group (self-reported zero or one concussion).
Athletes also provided their playing position, where the researchers then
grouped the athletes into non-speed (lineman) or speed (all other positions)
groups. The authors found that former college athletes with a high frequency of
concussions had lower white matter integrity compared to the low frequency
concussion group among college athletes. Within the professional group the low
frequency concussion group had lower white matter integrity. The authors also
found that non-speed players in the high concussion frequency group had lower white
matter integrity compared to the low concussion frequency group. Finally,
former players with lower white matter integrity tended to have worse outcomes on
functional MRI during working memory tasks.

The
authors found that recurrent concussion had an impact on white matter integrity
and functional neural recruitment (via analyzing working memory), which were
found to be dependent on playing position and career duration. It was
surprising to see that a longer football career does not appear to effect white
matter. However, playing position, specifically being a lineman resulted in
lower white matter integrity and more inefficient neural recruitment. This may
be attributed to the higher frequency of head impacts these players receive. These
athletes had normal neuropsychology testing and there were no differences
between college and professional test scores between low and high frequency
concussion groups. This suggests that measurable changes in white matter
integrity may precede cognitive and behavioral impairments. However, this will
need to be confirmed in a longitudinal study. Currently, medical professionals
should be aware of the playing position of their athletes, educate them on the
possible cumulative effects head impacts, and talking about this with coaches
and referees to ensure concussion protection rules/laws are being enforced.
Questions
for Discussion
: Do you think
monitoring white matter would be helpful for younger athletes? Do you think examining
head impact counts, decreasing contact practices, and recognizing/diagnosing
concussions would mitigate these changes later in life?
Written by: Jane McDevitt, PhD
Reviewed
by: Jeff Driban
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