Public Release: 

'Insufficient evidence' on degenerative brain disease in athletes

Wolters Kluwer Health

May 20, 2015 -- Available research does not support the contention that athletes are uniquely at risk of chronic traumatic encephalopathy (CTE) or other neurodegenerative disorders, according to a review in the June issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Wolters Kluwer.

Widely reported and publicized cases of CTE in retired athletes overlap with other neurodegenerative disorders, while the observed symptoms could result from a wide range of other factors, suggests the review by Dr. Gavin A. Davis of Cabrini Medical Centre in Malvern, Victoria, Australia, and colleagues. They write, "[We] think there is insufficient evidence to establish a causal relationship between sports participation and the existence of modern CTE."

Experts Question Link between CTE and Sports Over the past decade, a series of reports have described CTE as specific neurodegenerative disorder occurring in football players and other athletes. "Typically, sport-related CTE occurs in a retired athlete with or without a history of concussion(s) who presents with a constellation of cognitive, mood, and/or behavioral symptoms," according to Dr. Davis and coauthors.

Those reports have linked CTE to a history of concussions and "subconcussive impacts" during the athlete's playing career. However, because of the limitations of case series analysis, no direct causal link between concussion and CTE has been established.

Autopsy studies of athletes with CTE emphasize the presence of a protein called tau in specific areas of the brain. However, Dr. Davis and colleagues note that similar patterns of tau deposits are found in Alzheimer's disease and other common neurodegenerative disorders. These include the behavioral forms of frontotemporal dementia--the symptoms of which are "almost identical" to those of CTE.

The authors also note that a wide range of other factors can contribute to brain tau deposits, including genetic mutations, various drugs and toxins, environmental factors, and even normal aging. These factors can lead to conditions similar to CTE in people who are not athletes.

For example, tau deposits have been linked to substance abuse, including strong opiate pain medications--which are widely used by athletes. "It is likely that many of the cases with neuropathological findings represent the normal aging process, the effects of opiate abuse, or a variant of frontotemporal degeneration," Dr. Davis and coauthors write. They believe that in some cases, the clinical features may reflect depression or other mental health issues.

At a time of intense focus on the possible health effects of concussion and sports participation, Dr. Davis and coauthors hope their findings will draw attention to the limitations of the current evidence on CTE. They write, "When a previously undescribed condition, such as modern CTE in retired athletes, is proposed based on neuropathological findings in a small and potentially biased sample, then the complex genetic and environmental variables as well as the normal range of age-related brain degeneration implore us to cautiously review the data related to putative CTE."


Click here to read "Neurodegeneration and Sport."

Article: "Neurodegeneration and Sport" (doi: 10.1227/NEU.0000000000000722)

About Neurosurgery

Neurosurgery, the Official Journal of the Congress of Neurological Surgeons, is your most complete window to the contemporary field of neurosurgery. Members of the Congress and non-member subscribers receive 3,000 pages per year packed with the very latest science, technology, and medicine, not to mention full-text online access to the world's most complete, up-to-the-minute neurosurgery resource. For professionals aware of the rapid pace of developments in the field, Neurosurgery is nothing short of indispensable.

About Wolters Kluwer

Wolters Kluwer is a global leader in professional information services. Professionals in the areas of legal, business, tax, accounting, finance, audit, risk, compliance and healthcare rely on Wolters Kluwer's market leading information-enabled tools and software solutions to manage their business efficiently, deliver results to their clients, and succeed in an ever more dynamic world.

Wolters Kluwer reported 2014 annual revenues of €3.7 billion. The group serves customers in over 170 countries, and employs over 19,000 people worldwide. The company is headquartered in Alphen aan den Rijn, the Netherlands. Wolters Kluwer shares are listed on NYSE Euronext Amsterdam (WKL) and are included in the AEX and Euronext 100 indices. Wolters Kluwer has a sponsored Level 1 American Depositary Receipt program. The ADRs are traded on the over-the-counter market in the U.S. (WTKWY).

For more information about our products and organization, visit, follow @WKHealth or @Wolters_Kluwer on Twitter, like us on Facebook, follow us on LinkedIn, or follow WoltersKluwerComms on YouTube.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.