Posted by Matthew Mac Partlin on Wednesday, September 4, 2013

Concussion in sports and its associated complications have bubbled to the surface of public media again recently. And there may be wider implications to the latest development, which relates to the controversial entity known as Chronic Traumatic Encephalopathy, or CTE.

Competitors who suffer repeated concussion events are considered by many experts to be at risk of developing cognitive, behavioural, mood and somatic deficits that mirror forms of dementia later in life. This has become known as Chronic Traumatic Encephalopathy.

Its first official clinical description was written in JAMA (the Journal of the American Medical Association) in the late 1920s by a New Jersey pathologist called Harrison Martland, after a boxing coach reffered 23 cases to him. He described a syndrome of slurred speech, tremors, clumsy gait and slowed reaction and the term "punch drunk" became irrevocably associated with it. A few years later, the term 'dementia pugilistica' was coined. Later, in the 1970s, Corsellis described the neuropathology that he found when he autopsied the brains of 15 former boxers, which included cerebellar and cerebral atrophy. In the late 90s, an association was made with deposits of tau-protein neurofibrillary tangles and the ApoE4 gene.

Since then the condition has been described in athletes outside of boxing, largely in the realm of contact and field sports. There has been a concerted effort to define the condition, identify treatment strategies and most importantly, improve diagnostic methods; especially as it can currently only be confirmed pathologically at a post mortem examination. These efforts have led to the establishment in 2008 of the Center for the Study of Traumatic Encephalopathy at the Boston University School of Medicine.

Most recently, a paper was published that described two separate manifestations of CTE; a predominantly mood disorder that occured in younger patients and a predominantly cognitive syndrome that occured in older patients (Clinical presentation of chronic traumatic encephalopathy. Robert A. Stern et al. Neurology - Published online before print August 21, 2013, doi: 10.1212/WNL.0b013e3182a55f7f.).

However, all is not plain sailing. There is another group of concussion experts out there who question the existence of CTE as a valid entity. One of the main protagonists is a neuropsychologist named Christopher Randolph, who has written some searching articles that cast doubt on CTE's existence (Baseline neuropsychological testing in managing sport-related concussion: does it modify risk? Randolph C. Curr Sports Med Rep. 2011 Jan-Feb;10(1):21-6.).

The arguments that are most often used against the existence of CTE are:
  • the actual numbers of cases with co-existing demonstrable neuropathology are small overall, especially compared to the occurence of concussion in sport
  • the majority of the supportive literature is in the form of case series and descriptions, thereby valid only for association at best, but not causation
  • while there have been published descriptions of the anatomical neuropathology found in the brains of deceased CTE sufferers, there has been no published description of comparative populations such as competitors who suffered repeated concussions without developing CTE features
  • most, if not all, of the clinical features of CTE are non-specific and may simply be the manifestation of a non-concussion related dementia
  • almost all of the 'confirmed' cases also have a history of steroid use, alcohol or drug use, depression and/or other psychiatric problems

Finally, in the most recent iteration of the American Academy of Neurology Sports Concussion Guidelines (2012), recommendations regarding CTE were specifically not made and the guidelines could only state that "Prior concussion exposure is highly likely to be a risk factor for chronic neurobehavioral impairment across a broad range of professional sports" based on a collection of descriptive studies of varying quality (2 Class I studies, 6 Class II studies and 1 Class III), none of which conducted the gold-standard test of a post-mortem.

So why is any of this important?

Well, first of all, with respect to motorsport there is absolutely no data on this topic.

Secondly, last week there was a momentous court decision in the U.S.A. whereby a suit brought forward by lawyers representing about 4,500 former National Football League (U.S.) players against the NFL has been settled by the NFL for a total sum of US$765 million dollars, once approved by U.S. District Judge Anita B. Brody (read about it here, or just Google it). The allegation by the former players was that the NFL concealed awareness of the long term damage to players in the interest of protecting their commercial gains. Though the NFL has agreed to settle, the terms of the settlement include an agreement that the NFL will not be held liable nor will any health outcomes be deemed to have been caused by injuries recieved during play. The money is to go towards player and family compensation, medical care and future research. Players currently under contract are not included in the settlement, only former players.

Of note, the NFL for the past number of years has provided support for concussion initiatives, including the Centre for the Study of Traumatic Encephalopathy at Boston University.

The implications are huge.

CTE remains a contentious diagnosis, with both sides staunchly defending their stances. Yet a major class action has been found in the favour of the plaintiffs, resulting in what will be an enormous settlement, assuming it is approved by Judge Brody. Of course, she could reject the settlement and require that the case be heard. It suggests that whatever the state of the evidence for CTE, the NFL must believe that it has more to lose by continuing proceedings than by resolving the issue.

But it means a precedent has been set. So will we start to see other sporting groups start to take their regulatory bodies to court over this diagnosis? What does it mean for sports like motorsport, where that data simply isn't available? Given the size of the settlement, could it even result in the suppression of research in this area, resulting in a failure to ever really know what CTE really is?

Watch out.

And please leave your comments below. I'd like to hear your opinon on any of these issues.