Sports Medicine Research: In the Lab & In the Field: Are Early Markers For Neurodegeneration In Sight using Multimodal Imaging? (Sports Med Res)
Wednesday, November 29, 2017

Are Early Markers For Neurodegeneration In Sight using Multimodal Imaging?

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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