Spotting the silent signs: A guide to concussion symptoms

Many lament the good old days of NRL brawls, AFL hip and shoulders, and rugby’s massive hits but concussion risk has rightly become a hot topic in sport.

I loved schoolboy rugby, despite not having much natural talent. I was a late bloomer and got crushed by bigger blokes but I learned something from leaning into tackles (not shying away). I think contact sports are a rite of passage for teenage men.

Although many of us don’t play contact sports anymore (despite not being past our prime!), concussion is an interesting subject and is most likely of concern to parents during Saturday sports.

How to identify the signs and symptoms of concussion

Things to look out for on the field and afterwards [1].

On-field signs of concussion

• Loss of consciousness
• Lying motionless, slow to get up
• Seizure
• Confusion, disorientation
• Memory impairment
• Balance disturbance or motor incoordination
• Nausea or vomiting
• Headache or 'pressure in the head'
• Visual or hearing disturbance
• Dazed, blank/vacant stare
• Behaviour or emotional changes, not themselves

Further red flags to look for

• Neck pain
• Increasing confusion, agitation or irritability
• Repeated vomiting
• Seizure or convulsion
• Weakness or tingling/burning in the arms or legs
• Deteriorating conscious state
• Severe or increasing headache
• Unusual behavioural change
• Double vision

What causes concussions?

The primary hypothesis is that the shearing forces suddenly disrupt brain function and result in mismatched glucose supply/demand that causes concussion symptoms:

• Neuronal depolarisation: A large efflux of potassium following neuronal stretching
• Local lactic acid: Sodium-potassium pumps attempt to restore homeostasis by using ATP, which requires glucose and results in lactic acid byproducts
• Decreased cerebral blood flow: Calcium influx constricts blood vessels and inhibits blood flow

It should be noted that concussion is complex and our understanding is still evolving [2]. 

What activities are the greatest risk?

Sure, contact sports are the most likely place to be concussed with c.3-10 concussions per 1,000 player hours [3], but cycling and skiing are common drivers.

20% of hospitalisations for concussions have been due to cycling in the last few years [4].

Why it’s important to avoid repeated concussions

There has long been an association between repetitive concussions and chronic complications; it was initially coined “punch drunk” in boxers in the 1920s [5] and is now known as Traumatic Encephalopathy Syndrome [6].

Repeated concussions can progressively deteriorate into TES, resulting in cognitive impairment and/or neurobehavioral dysregulation (e.g. explosiveness, impulsivity, rage, violent outbursts). This is serious stuff but the approach to diagnosis (biomarkers, imaging, etc) is still evolving [7].

Although there appears to be an association between multiple concussions and cognitive deficits later in life [8], there has not yet been a high-quality study to fully evaluate the link between concussion and TES by controlling for other factors: smoking, sleep apnoea; etc [6].

How to protect against concussion?

Peripheral vision training (to avoid head knocks) and stronger neck musculature (to absorb impact) may help reduce concussion risks [9][10][11]. However, this isn’t included in the formal framework yet as the evidence is inconclusive [12].

Although there’s mixed evidence on whether dehydration increases the concussion risk [13], it does appear to amplify symptoms so hydration is an important treatment consideration.

Unfortunately, there is currently little evidence that existing protective gear (helmets, headgear, and mouthguards) reduces concussion risk [14] except for a single study in hockey that has not been replicated [15].

Nevertheless, they provide great protection against skull fractures and facial/dental traumas and should be used [14].

Given all of this, the main focus should be on reducing head knocks and as a result, sporting rule books have been evolving more recently [16].

How to manage concussion?

It’s important to take concussion seriously. If you or those around you suffer a head knock, find a safe space (e.g. off the field) to evaluate symptoms and apply the decision tree shared above.

The prevailing approach involves hydration, initial rest, and a gradual return to activity overseen by a medical practitioner to help subside symptoms and accelerate recovery [17].

It’s a myth that you shouldn’t sleep after a concussion as sleep is important to recovery, however, it’s critical to monitor for a deterioration in symptoms as this may suggest intracranial bleeding — go to hospital if unsure. Avoid NSAIDs as this may increase the risk of bleeding.

What technologies are emerging? 

There’s lots of interesting tech in the space ranging from smart mouthguards [18] to portable equipment for immediate off-field assessment using EEG methods [19]. Blood tests for Tau — an inflammation biomarker linked to Alzheimer’s — might also become part of the toolkit [20]. 

The pathophysiology of concussion is complex and our understanding is evolving but I hope more awareness, rule changes, and equipment tech will allow players to continue enjoying contact in sport. 

This post contains general information about health and wellness practices. It is not intended as medical advice and should not be treated as such. Please consult with a healthcare professional before starting any new health regimen. This information is provided without any representations or warranties, express or implied.