DIAGNOSING concussion during a game is the most difficult diagnosis a sports doctor can make, one of the world's leading concussion experts says.

On the day the AFL announced the introduction of a concussion sub rule and new guidelines, Canadian professor Willem Meeuwisse said that the evolving nature of a concussion and the different effects head knocks can have on each individual made it a tough assessment for doctors.

That was why significant time was needed for doctors to make an assessment.

Under the new rules, players taken from the ground for concussion assessment will be off for 20 minutes.

The doctor will wait 10 minutes for the player to move towards a restive state before beginning the assessment.

Club doctors will have access to video footage that will give them information on the effect the knock has had.

Meeuwisse, the keynote speaker at a two-day concussion conference at Etihad Stadium, said the AFL was the first sport in the world to make a change based on the Consensus Statement on Concussion that was released last week.

"I think where the AFL's been a real leader is they've set up their timeframe in a way that allows a full evaluation," Meeuwisse said.

The rule will release some pressure on the club doctor, but logic suggests their role will be very difficult to perform if other injuries take place while a concussion assessment is taking place.

AFL medical officer Dr Peter Harcourt said that history and an expected conservative approach to concussion suggested there would be one assessment per game.

Under the new rule if a substitute player is available when a doctor decides a player needs to be assessed then they can be used as a temporary replacement for the injured player.

If the player is diagnosed as being concussed he will be permanently subbed from the game. If an assessed player is found to be OK he can return to the ground after 20 minutes and the temporary substitute resumes his position as a sub.

"For the AFL, it's about player health and welfare and being conservative in an environment where there's a lot of questions floating around about the long-term consequences of head injuries," Harcourt said.

The AFL will announce on Thursday it has entered into a collaborative partnership with the Melbourne-based Florey Institute of Neuroscience and Mental Health to conduct scientific research into concussion and mild traumatic brain injury.

They will seek $3 million in third party funding support to enable the full scope of planned research to proceed.
The Florey Institute has been responsible for an MRI imaging pilot program in the past five seasons with AFL players.

It is considered a world leader in such research.

The AFL intends to bring its concussion research projects under the umbrella of the Florey Institute partnership to ensure they are undertaken in a way that complements the overarching scientific approach and will commit further funding to the partnership.
Projects are expected to be rolled out under the agreement for the next five to 10 years.