How the NRL's concussion test actually works

It's become one of the most important challenges in the game, but how does the NRL's concussion test actually work?

We've taken a look through guidelines from both the NRL and the SCAT Test to bring you a (hopefully) simplified guide, mainly focused on the doctor's role with the player.

Firstly, a trainer must make an initial assessment of injury.

If a player is exhibiting any of the five key symptoms of a head injury, the trainer must take him from the field for further testing.

That's when the team doctor steps in.

Firstly the doctor will review vision of the incident in question, and conduct a neck injury assessment.

Then the SCAT test will begin - a test currently known as 'SCAT3 - Sports Concussion Assessment Tool - 3rd Edition'.

The test begins with a symptom evaluation in which the doctor asks a range of questions about how the player is feeling.

The doctor is then required to assess how different the player is acting and feeling to their normal self.

The test then moves on to the cognitive assessment which begins with orientation questions, often including the following:

What month is it?
What is the date?
What venue are we at today?
Which half is it now?
Who scored last in this match?
Did your team win the last game?

Players are then tested on their immediate memory, with the doctor reading out a list of words before asking the player to repeat back as many as possible.

Then the hard stuff begins as players are tested on their concentration.

At this stage of the test the doctor reads out a string of numbers, with the players required to repeat them back in reverse order.

The doctor will read out increasingly long strings of numbers to test the player.

Then it gets really hard, as the player is put through a more difficult concentration test, which often involves saying the names of months in reverse order.

This part of the test tripped up Jack Bird after he was knocked out by Martin Taupau in 2016.

A teammate told media he "couldn't get past October" as he attempted this part of the test.

This challenge can be difficult for anyone, let alone an exhausted (or concussed) footy player, which explains why so many fail the head injury assessment.

The doctor then gets the player to undergo balance and coordination assessments.

The player then undergoes a delayed recall test, in which they are asked to remember as many words as possible from the earlier memory test.

That concludes the testing process for the doctor.

As we know, if the player passes the test and manages to return to the playing field within ten minutes, the team is not charged with a substitution.

However doctors are advised to take as much time as possible, and to repeat the test if need be, if they are still unsure about the player.

If the player fails any part of the test however, they should not be allowed to return to the field.

It should be noted that different clubs and doctors may use slightly different versions of this test.