Home » Repetitive Head Impacts Damage The Brain: A 'No Brainer,' Purdue Researchers Find

Repetitive Head Impacts Damage The Brain: A 'No Brainer,' Purdue Researchers Find

Eight recent studies show neurocognitive and neurophysiological effects of subconcussive blows

  • That DMN connectivity did not return to pre-season levels during the post-season was a "cause for concern," they said, as it suggested that, "even at sub-concussive levels of head impacts, there is neural reorganization and no true return to 'normal,' which, in turn, suggests that neural plasticity could be acting as a compensatory mechanism to keep football players asymptomatic."   As Thomas Talavage, a professor of electrical and computer engineering and biomedical engineering and co-director of the Purdue MRI facility, told Purdue News,[11] "The brain is pretty amazing at covering up a lot of changes. Some of these kids have no outward symptoms, but we can see their brains have rewired themselves to skp around the parts that are affected."
  • athletes exposed to RHI exhibited significant abnormalities in the white matter of the brain during the season which increased as the season wore on, and persisted after the season.[10] Interestingly, the data suggested that the greater number of lesser intensity collisions experienced by the members of one football team resulted in injury at the cellular level (inflammation of the axons, which are like cables woven throughout brain tissue), while a lesser number of high intensity collisions experienced by the second team may have been more injurious to the fiber structure of the brain.  While the researchers said it was an "open question" whether one or the other may be of more clinical significance, the bottom line was the same: that the injury to the white matter of the brain was "slowly accumulating, with magnitude and number of events affecting the nature of the observed changes." 
  • Along with the findings by other researchers over the past five years linking repetitive head impacts to increased susceptibility to concussion, decreased cognititive function, altered gray matter functional connectivity, and changes in white matter microstructure, and theorizing that, in the long term, retired football players who have sustained high levels of subconcussive impact over their careers are at increased risk of developing neurodegenerative disorders, like amytrophic lateral sclerosis (i.e. Lou Gehrig's disease), Alzheimer's disease, Parkinson's disease, and chronic traumatic encephalopathy (CTE),[12] the Purdue studies suggest that science is inching closer to an understanding of the neurocognitive, metabolic, cerebrovascular, and brain gray and white matter changes resulting from concussion and from the accumulation of sub-concussive blows.  

    Finding the holy grail 

    Whether scientists will ever find the head trauma "holy grail": a threshold - whether it is number of hits per week, over the course of the season, of a certain magnitude (both in terms of linear and/or rotational acceleration, or to a certain part of the helmet (e.g. facemask, top of the head) above which a player exposed to RHI is at significantly increased risk of permanent neurocognitive impairment or, worse, degenerative neurological conditions such as chronic traumatic encephalopathy, needed to help guide the development of preventive strategies, is, however, very much an open question.

    "We'd like to get to the point where, now that we know we can observe with imaging how the brain changes with exposure [to subconcussive blows], we can intervene to change the hardware, change the helmets, change techniques and training regimens," said Larry Leverenz, clinical professor in the Department of Health and Kinesiology, in an interview with Purdue News.

    To that end, the Purdue researchers are working to develop helmet technologies that absorb more energy than conventional helmets to better protect the brain, and have formed the Concussion Neuroimaging Consortium with seven other universities to garner support and funding for research into the neurological effects of contact sports.  

    Unfortunately, there appears to be little funding for studies like that those done at Purdue.  As one researcher observed, "Everyone is focusing on only looking at concussions after-the-fact, rather than trying to gain a meaningful understanding of what takes place prior to the injury.  This is unfortunate, as we know from many soft tissue injuries that 'symptoms' (effectively, 'failures') are late-developing situations, with structural and functional changes typically preceding the 'diagnosis' of something being wrong. 

    Another concern, some researchers say, is that the timelines for developing and testing cutting edge technology, especially new telemetry devices (i.e. impact sensors) and for predictive modeling of neurological changes that could be used to meter head impacts in, say, practices, is so long (approaching five or six years), that it is not within the window of current entrepreneurship models, given the current venture capital/angel investor climate. In the absence of government funding from the National Institutes of Health or the National Science Foundation, which, according to one researcher, is unlikely, the problem might never be solved. 

    1. Talavage T, Nauman E, Breedlove E, et. al. Functionally-Detected Cognitive Impairment in High School Football Players Without Clinically-Diagnosed Concussion. J Neurotrauma. 2010; DOI: 10.1089/neu.2010.1512. 

    2. Talavage TM, Nauman EA, Breedlove EL, et al. Functionally-detected cognitive impairment in high school football players without clinically diagnosed concussion. J Neurotrauma. 2014;31(4):327-338. doi:10.1089/neu.2010.512.

    3. Breedlove KM, Breedlove EL, Robinson M, Poole VN, King JR, Rosenberger P, Nauman EA. Detecting neurocognitive & neurophysiological changes as a result of subconcussive blows in high school football athletes.  Ath. Tr. & Sports Health Care. 2014;6(3):119-127

    4. Poole VN, Breedlove EL, Shenk TE, Abbas K, Robinson ME, Leverenz LJ, Nauman EA, Dydek U, Talavage TM.  Sub-concussive HIt Characteristics Predict Deviant Brain Metabolism in Football Athletes. Developmental Neuropsychology 2015;40(1):12-17, DOI:10.1080/87565641.2014.984810.

    5. Nauman EA, Breedlove KM, Breedlove EL, Talavage TM, Robinson ME, Leverenz LJ. Post-Season Neurophysiological Deficits Assessed By ImPACT and fMRI in Athletes Competing in American Football.  Developmental Neuropsychology. 2015;40(2):85-91. doi:10.1080/87565641.2015.1016161.

    6. Robinson ME, Shenk TE, Breedlove EL, Leverenz LJ, Nauman EA, Talavage TM.  The Role of Location of Subconcussive Head Impacts in fMRI Brain Activation Change. Developmental Neuropsychology 2015;40(2): 74-79. doi:10.1080/87565641.2015.101224.

    7. Shenk TE, Robinson ME, Svaldi DO, Abbas K, Breedlove KM, Leverenz LJ, Nauman EA, Talavage TM. fMRI of Visual Working Memory in High School Football Players.  Developmental Neuropsychology 2015;40(2):63-68. doi:10.1080/87565641.2015.1014088

    8. Svaldi DO, Joshi C, Robinson ME, Shenk TE, Abbas K, Nauman EA, Leverenz LJ, Talavage TM. Cerebrovascular Reactivity Alterations in Asymptomatic High School Football Players.  Developmental Neuropsychology 2015;40(2):80-84. doi:10.1080/87565641.2014.973959.

    9. Abbas K, Shenk TE, Poole VN, Robinson ME, Leverenz LJ, Nauman EA, Talavage TM. Effects of Repetitive Sub-Concussive Brain Injury on the Functional Connectivity of Default Mode Network in High School Football Athletes. Developmental Neuropsychology 2015;40(1):51-56. doi:10.1080/875665641.2014.990455. 

    10. Chun IY, Mao X, Breedlove EL, Leverenz LJ, Nauman EA, Talavage TM. Detection of Longitudinal WM Abnormalities Due to Accumulated Head Impacts. Developmental Neuropsychology 2015;40(2):92-97. doi: 10.1080/87566541/2015.1020945. 

    11.'Deviant brain metabolism' found in high school football players. Purdue University News. August 19, 2015. (accessed at http://www.purdue.edu/newsroom/releases/2015/Q3/deviant-brain-metabolism...)

    12. Reynolds BB, Patrie J, Henry EJ, Goodkin HP, Broshek DK, Wintermark M, Druzgal TJ.  Practice type effects on head impact in collegiate football. Published online August 4, 2015; DOI:10.3171/2015.5.JNS15573.

    Posted August 31, 2015, most recently updated October 20, 2015