Sports Medicine Research: In the Lab & In the Field: Despite the Hype: Many Former NFL Athletes May Have Normal Neurological Function and Structure (Sports Med Res)


Wednesday, July 23, 2014

Despite the Hype: Many Former NFL Athletes May Have Normal Neurological Function and Structure

Is there chronic brain damage in retired NFL players? Neurology, neuropsychology, and neurology examinations of 45 retired players

Casson IR., Viano DC., Haacke EM.,Kou Z., LeStrange DG. Sports Health 2014;ahead of print.

Take Home Message: Neuropsychological impairments were found in some players; however, the majority of retired NFL players had no clinical signs of chronic brain damage. Some retired players had lesions found on brain imaging tests and these were associated with the number of previous concussions.

Evidence of neuropathology in the brains of deceased football players has led to widespread concern for retired players. Survey studies have suggested that depression and cognitive problems occur in retired NFL players; however, there is not much information reported on the neurological, neuropsychological, and neuroradiological examination of living, retired NFL players. Therefore, the authors performed clinical neurological, neuropsychological, and neuroroadiological examinations on 45 living, retired NFL players (on average 46 years of age, 31kg/m2 BMI, 6.8 years of playing experience, and 34 reported 3+ previous concussions). Participants’ histories focused on neurological and depression symptoms, exposure to football on-field time, and other factors that could affect the brain function. A neurological examination followed, which consisted of Mini-Mental State Evaluation, Beck Depression Inventory, and Patient Health Questionnaire. The neuropsychological portion of the study included a pen and paper exam created by 5 neuropsychologists and an ImPACT exam. Neuroradiological analyses consisted of magnetic resonance imaging (MRI) utilizing susceptibility weighted imaging and diffusion tensor imaging. Finally, the examination concluded with a blood draw for APOE genotyping and blood chemistry analysis. Up to nine retired players had moderate to severe depression depending on which criteria the authors used. Depression scores were not associated with football exposure. The neuropsychology examination demonstrated that none of the players had dementia; however, 24% had some memory impairment. Susceptibility weighted imaging MRI correlated with family history of neurological disease, and number of “dings” (un-diagnosed concussions) at all football levels (high school through professional). Four retired players had microbleeds (detected using the susceptibility weighted imaging MRI) and these may be associated with number of dings in football career. Seventeen retired players carried at least one copy of the APOE E4 allele (the allele that has been associated with onset of Alzheimer’s due to head impact). Diffusion tensor imaging detected that there was lower fiber density, myelination, and axonal diameter with participants carrying the APOE E4 allele. Additionally, being “dinged,” while playing contact sports other than football and previous concussions were also associated with APOE E4 allele.

This is an interesting study because it is one of the first studies that performed a thorough clinical evaluation of retired, living NFL players. It is encouraging to see that the percentage of participants that demonstrated moderate to severe depression was in line with the general public (~15-20%). Though, there were no diagnosed cases of dementia, 24% of retired players showed some memory impairments and there were abnormalities seen with imaging techniques. Abnormal imaging were associated with higher number of football concussions no matter what level of play, which suggests that there needs to be more conservative management of football players with previous concussion history. Finally, 34% of the participants carried the APOE E4 allele, which is higher than the general population (~24%). This is important because this genetic variation is associated with the onset of Alzheimer’s. While many have been quick to criticize football because of the risk for long-term neurocognitive impairment. This study reminds us that many football players may have normal long-term neurocognitive health. Much like with the risk of sudden cardiac death in sports we need to strive to identify better ways of recognize which athletes may be susceptible to neurocognitive impairments (for example, testing for APOE E4 genetic variations).  Alternatively, we can adopt the approach that we are using to protect long-term joint health by exploring new injury prevention programs but with a concussion focus.

Questions for Discussion: Should sports medicine clinicians provide care for retired athletes? How often should retired athletes, like NFL players, receive examinations? Should extra care only be given to NFL athletes with documented concussions?

Written by: Jane McDevitt, PhD
Reviewed by: Jeff Driban

Related Posts:

Casson, I., Viano, D., Haacke, E., Kou, Z., & LeStrange, D. (2014). Is There Chronic Brain Damage in Retired NFL Players? Neuroradiology, Neuropsychology, and Neurology Examinations of 45 Retired Players Sports Health: A Multidisciplinary Approach DOI: 10.1177/1941738114540270


Timothy said...

First, I think it is critical to continue to treat athletes following the conclusion of their playing career. When athletes suffer ACL injuries, we in sports medicine/orthopedics treat them when they develop OA! Since other sources have reported long term effects, continued treatment following retirement could help prevent those consequences.
Secondly, it is important to remember that some of these were the same NFL authors who were originally critical of the literature on CTE in the NFL. This causes me to be caution of their findings until it can be corroborated externally. That being said, I applaud their reporting of their data set in the appendices and use of outside scientists to collect and analyze data.

Jane McDevitt said...


I do agree that continued treatment is necessary, but I am wondering how often should players receive full imaging and lab tests run after they retire. If the research findings continue to find no connections to CTE then maybe yearly or bi-yearly would be suffice. Continued research is necessary to set the standard of care following retirement.

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