Head and Brain Injury in Hockey

Recent incidents of brain trauma in hockey have been visible and covered in the media.

When another player collided with the side of her head, it ended Nicola While’s career. An innocuous shoulder to the side of her head left Shona McCallin with a debilitating brain injury. Katie Shanahan had a shot straight in the area between her eyebrows that finished her career. Tom Wilson died instantly after a blow to the head in training while playing for his club Old Loughtonians in Essex. Sam Ward was preparing for the 2020 Olympics when he was struck in the head by a ball and left near-blind in his left eye.

Head impacts and brain injuries are frequent occurrences in hockey, and are thought of as almost ingrained in the culture of the game.

GB & England Hockey have been a primary supporter of the 2008, 2012 and 2016 Concussion in Sport Consensus Meetings.

These guidelines are meant to ensure that players who suffer concussions are managed effectively to protect their short-and long-term health and welfare. However, the Concussion in Sport group has been criticised for its current and past relationships with large sports organisations. Their position has been discredited for their view that there is no cause-and-effect relationship between concussion and degenerative brain diseases ^[1].

More concussion data and injury analysis in hockey are needed for a better understanding of the long-term consequences of brain injury in hockey.

40% of the hockey injuries sustained in women and 27% in men ^[2] were to the head and face, making it the most common injury at major international hockey tournaments.

The most common collision is with another player that results in an impact to the side of the head. This was followed by contact with either a stick or the ball.

Midfielders and attacking forwards are the positions that sustained the highest number of concussive injuries, and the risk of sustaining a concussion was six times higher in a game compared with training ^[3].

An impact on the head or body sends a strong force to the brain, resulting in a concussion or brain injury. Symptoms include:

• Headache;
• Mental fogginess;
• Changes in memory, balance, coordination, behaviour, irritability; and
• Slowed reaction time.

Over 90% of concussions do not show as loss of consciousness and more than 80% of concussions are diagnosed the next day or several days later.

Sub-concussions occur when the impact damages brain cell function, but a player does not experience any symptoms and the impact is unnoticed. Repetitive sub-concussions injure the fine blood vessels in the brain. This damages the ‘blood-brain’ barrier, a structure that protects the brain.

When this is damaged by repetitive trauma, an abnormal inflammatory response is triggered by the production of neurochemicals. The neurochemicals and inflammatory response should be protective. However, the problem arises when the brain is subjected to repetitive impacts before the protective neurochemicals and inflammatory changes from the initial head injury have had time to return to normal.

Repeated head injuries can lead to an overproduction of neurochemicals, and an exaggerated inflammatory response which is harmful to the brain, rather than protective.

This damages brain tissue and results in the irreversible death of brain cells. Over time, this leads to changes in the tau protein in the brain.

Responsible for neurodegenerative disease, tau protein normally allows cognitive brain cells to work together and communicate efficiently. However, when it becomes damaged through repeated injury, the cognitive cells can no longer perform. As this damaged tau protein spreads, more of these brain cells are killed and a person will begin to display behavioural changes and a lack of control over their emotions.

Brain injury is not specific to elite hockey, it is very much part of the amateur game. It can impact men, women, children, whatever age and fitness level. Also, as the age and skill of players decreases, the likely risk of brain injury increases.

GB & England Hockey guidelines focus on:

• Recognise – Learning the signs and symptoms of a concussion to spot it in athletes;
• Remove – If an athlete has a concussion or even a potential concussion, they must be removed from play immediately;
• Refer – Once removed, the player should be referred immediately to a medical practitioner or qualified healthcare professional who is trained in evaluating and treating concussions;
• Rest – Players must rest from exercise until symptom-free and then start a Graduated Return to Play program;
• Recover – Full recovery from the concussion is required before a return to play is authorised. This includes being symptom-free. Rest and specific treatment options are critical for the health of the injured participant; and
• Return – In order for a safe return to play in hockey, the athlete must be symptom-free and cleared by a medical practitioner or approved healthcare professional who is trained in evaluating and treating concussions.

The GB & England Hockey guidelines do not reference sub-concussive impacts. These are frequent, smaller impacts that create accumulated sub-clinical brain injury and trigger longer-term neurodegenerative consequences, such as Chronic Traumatic Encephalopathy (CTE).

The risk and severity of CTE are caused primarily by multiple smaller, sub-concussive impacts, and not by one-hit concussions. 20% of people with CTE diagnosed afterlife were recorded as never having sustained a single concussion.

This type of brain injury happens at the microscopic level, c. 4,000 times smaller than the eye can see on a regular brain scan. This makes it all the more pernicious because it is incredibly difficult to diagnose and treat.

A graduated return to play (GRTP) is a program that introduces an individual back to sport in six steps. Younger athletes who sustain a concussion are managed more conservatively.

Hockey recommends different minimum rest periods and different length GRTP stages for differing age groups.

Under current GRTP Guidelines:

• Players up to 18 years can complete the GRTP in a minimum of 23 days.
• Players over the age of 18 years can complete the GRTP in a minimum of 6 days.

Despite females being more susceptible to concussion and sub-concussions, experiencing worse and more prolonged symptoms, there are no specific return to play guidelines for female players.

GRTP is really an informed guess on how long it takes the brain to recover post-injury. Damage to the brain cells from an impact can occur both immediately (damage to the brain cell structure) and later (blood flow changes or neural inflammation). Research and opinion from medical literature reviews suggest that 30 days is the minimum period before returning to play following a concussion event. Changes in white matter, brain connections and blood flow can persist a year or more after a concussion.

A too-soon return can, in fact, increase the risk of further injury and subsequent symptoms, requiring a prolonged period of recovery.

Research ^[4] shows a relation between a history of concussion and lower extremity injury, especially lateral ankle sprain, knee injuries and muscle strains. Athletes at all levels in sports have a greater risk of lower-body injury issues for more than a year following a sport-related concussion. In some cases, this risk is as high as 67%.

While hockey goalkeepers wear head-to-toe protection including helmets during games, outfield players only put on masks for penalty corners.

Short corners (arguably the most dangerous aspect of hockey) have been analysed significantly, and the protection worn by the players during these instances has increased over the past few years. Plastic masks were introduced in 2015, but only for short corners.

Despite the dangers, no headgear is used throughout the rest of the match. Under FIH rules (01.01.22), the use of protection away from penalty corners is only permitted for medical reasons. Interestingly, reducing brain injury and the risk of neurodegenerative disease e.g. CTE is not seen as a medical risk for all, but by exception.