Concussion: common interests, quality research drive better outcomes

AS a scientist who has worked to understand and reduce head injuries over three decades, I wish to set the record straight on progress in managing concussion in sport over that period, provide clarity on interpretation of the limited evidence, highlight the importance of engaging with sporting organisations in order to effect change, and outline future directions.

Progress in managing concussion in sport

In 1994, the National Health and Medical Research Council (NHMRC) published the report Football injuries of the head and neck. The scope of the report was to inquire into head and neck injuries resulting from participation in football (all codes) and suggest ways of minimising injuries.

The report panel included medical practitioners with specialist training in relevant disciplines, some of whom represented the main football codes.

The report highlighted that the terms “mild head injury” and “mild concussion” were not interchangeable. The authors were careful to note that concussion can result in a wide variety of symptoms which are usually transient and “does not result in immediately detectable structural injury”. These concepts have continued to inform the diagnosis and management of concussion in sport.

Another important observation was that football codes managed diagnosis and return-to-play decisions differently, with rugby union having a mandatory 3-week recovery period. The authors noted that mandatory recovery periods may have perverse outcome; for example, players minimising the concussion symptoms.

Long term problems were considered. The authors considered research papers that described neurospyschological impairments in retired Scandinavian soccer players, explained as the consequences of heading the ball, and in 40% of the control group. The authors wrote: “the pattern of deficits is equally consistent with alcohol-related brain impairment”.

In contrast to Buckland and colleagues’ assertions in Concussion in sport: conflicts of interest drive scandal, the panel set ambitious recommendations for improving the prevention and management of concussion.

What has occurred in Australia and internationally is the exact opposite of the paralysis described by Buckland and colleagues. There has been a continuous cycle of improvement involving research, policy and practice since the mid-1990s. The single change that enabled these improvements was the recognition that concussion was an injury rather than a reflection of an athlete’s toughness. As a result, athletes can be:

• removed from a game and assessed on the suspicion that they have been concussed;
• prevented from returning to play in the same game;
• provided with a graduated return to play pathway; and
• counselled to retire as a result of multiple concussions.

These changes to policy and practice are based on science. Far from our understanding of concussion going backwards, great progress has been made in aetiology, assessment, diagnosis, prevention, management and return-to-play protocols.

Policy and practice have been totally transformed in professional sport since the mid-1990s. It is more challenging in community sport and greater attention is required to ensure that suitable concussion protocols are implemented.

Many Australians across many disciplines have been instrumental in driving improvements in the management of concussion in sport locally and internationally. In my opinion, Buckland and colleagues misrepresent the success of the International Conferences on Concussion in Sport, and the associated consensus statements and thematic reviews, in delivering on the 1994 NHMRC report recommendations for the benefit of athletes.

A very important clinical tool produced through the International Conferences on Concussion in Sport meetings with the support of professional sports is the Sport Concussion Assessment Tool (SCAT). Far from there being an attempt to hide concussion, SCAT 1 (2004) recommended: “Any athlete suspected of having a concussion should be removed from play, and then seek medical evaluation.”

SCAT 2 (2009) began to provide guidelines on return to play, which focused on a stepwise symptom-limited program. SCAT 3 (2013) highlighted the following instruction from SCAT 2 (2009): “no athlete diagnosed with concussion should be returned to sports participation on the day of injury”, and provided more guidance on return to play, including medical clearance before commencing a supervised stepwise program and return-to-play, and referral to a medical practitioner specialised in concussion management if the athlete was symptomatic for more than 10 days. SCAT 5 (2017) provides even more guidance on specific topics, such as return to school.

SCAT identifies the central role of medical practitioners in caring for the athlete through diagnosis, management and managing return to play.

Clarifying the interpretation of the existing research

In my opinion, Concussion in sport: conflicts of interest drive scandal is misleading on multiple fronts. The authors seem to be confident about the aetiology of chronic traumatic encephalopathy (CTE) and the uniqueness of their view around a link between repetitive head injury and long term neurodegeneration, when the former is uncertain and the latter is hardly controversial.

Solomon and colleagues (2014) identified traumatic brain injury as one of multiple risk factors for late-onset dementia and Alzheimer’s disease, highlighting that: “The amount and quality of available evidence varies considerably between these factors”.

This is certainly the case with regards to CTE where the quality of evidence is limited, historical measurement of head impact exposure is non-existent, and the presence of other risk factors may be unknown.

If there is a dose–response relationship between exposure to head impacts that do not cause injury (“subconcussive impacts”) and CTE, we are a long way from discovering it. If there is a dose–response relationship between concussion and CTE, efforts to prevent concussion and manage better return-to-play will reduce the risk.

Buckland and colleagues conflate the distinct entities CTE, concussion, repetitive head injury and subconcussion, in my opinion.

From my biomechanics discipline perspective, the statement “… lifetime cumulative exposure to repetitive head injuries (both concussions and subconcussive blows) is the single biggest known risk factor for CTE” encapsulates the misconception. “Subconcussion” is not a head injury and “head injuries” could include anything from concussion to intracranial haemorrhage.

The operational definition of concussion in sport is broad in terms of signs and symptoms, but excludes structural brain injury. Even with this broad concussion definition, head impacts occur that do not result in any symptoms. If we classified “subconcussive impacts” as any direct or indirect head impact that does not cause concussion, this category includes changes in the head’s acceleration related to sprinting, jumping, landing and heading soccer balls.

Scientists, health professionals and athletes must work with sports bodies to effect change 

Dr Buckland and his colleagues are focused on CTE and suggest that the key to the delivery of guidelines and risk mitigation strategies will be enlisting the support of experts with no ties to sporting bodies.

Dr Bob Cantu, co-founder and medical director of the Concussion Legacy Foundation (CLF), has been a regular participant in the International Conferences on Concussion in Sport from 2001. The CLF has a focus on CTE and states: “Drs Cantu and Nowinski also advise numerous sports organizations, including the National Football League [NFL], NFL Players Association, the Ivy League, [the National Operating Committee on Standards for Athletic Equipment (NOCSAE)], and World Rugby, to create change from the top down”. Chris Nowinski is a retired professional athlete. Drs Cantu’s and Nowinski’s history of involvement in sport and their declared activities reflect the reality that it is essential for those seeking to improve athlete health and welfare to work with sports.

By necessity, research has been conducted with the involvement of the main football codes. They are responsible for implementing changes to policy or practice. There are many experts working within the football codes who improve the quality of the research and assist in connecting the researcher to the football community. In my own dealings with the main football codes, I have not felt pressured to produce a specific outcome or experienced any censorship, even when the football code has fully funded the research. While many university-based researchers groan at the often glacial pace of contract negotiations between the research office and funding partner, the fact of the matter is that academics will have the right to publish. This is a situation well understood by experienced funding partners.

Future directions

There is clearly a need for continued high quality research on multiple topics, such as recovery and susceptibility to repeat concussion.

With our current work (2021–2022) on setting guidelines for head acceleration measurement (Consensus Head Acceleration Measurement Practices, supported by the NFL) and sensor development, we may reach the position where accurate and reliable on-field head impact exposure measurement is possible. This will be key to establishing better protocols for concussion management, concussion prevention, and investigating links between head impact exposure and neurological disease. In my opinion, it is also important that Australian Football League and the rugby football codes grasp the opportunities to reduce concussion through better performing padded headgear.

There has been a substantial cultural change within the football codes regarding concussion. Policy and practice changes have been implemented and updated to deal with the primary issue which is concussion. Within the timeframe from 1994 to 2022, debate over CTE has arrived late and is informed, so far, by weak and confounded evidence. The changes that are suggested by concerns regarding CTE are profound for sport and health. Therefore, a continued focus on preventing and managing concussion, coupled with high quality research, is sensible and may minimise medium to long term neurological disease.

Dr Andrew McIntosh is a self-employed consultant in biomechanics and ergonomics with a special interest in impact injury biomechanics, safety and personal protective equipment performance standards. He is an adjunct associate professor at Monash University Accident Research Centre and adjunct professor at the School of Engineering at Edith Cowan University. He has researched head injury biomechanics, concussion in sport and injury risk management in sport since the 1990s. He has received research funding directly or via university contracts from the AFL, World Rugby (formerly the IRB), Rugby Australia (formerly the ARU), the International Olympic Committee, FIFA, Cricket Australia and Racing Australia. He participated in the International Conferences on Concussion in Sport in 2001, 2012 and 2016.

 

The statements or opinions expressed in this article reflect the views of the authors and do not necessarily represent the official policy of the AMA, the MJA or InSight+ unless so stated.

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