The Premier League agreed on Wednesday to introduce a trial for permanent concussion substitutes, allowing up to two extra changes per team in a match.

The International Football Association Board (IFAB), the guardian of the laws of the game, approved such experiments in December.

No date has yet been set for the start of the trial as the reporting process, including private medical information, is still to be resolved with IFAB and FIFA.

"With player welfare the Premier League's priority, the protocols will allow a maximum of two concussion substitutes to be used per team, with the opposition side able to use the equivalent number," the Premier League said in a statement.

"The additional concussion substitutions may be made regardless of the number of substitutions a team have made already.

"The trial is a result of the IFAB's consultation with stakeholders and recommendations from their concussion expert group to allow additional substitutions for players with actual or suspected concussion."

By allowing both sides an extra substitution whenever there is a suspected case of concussion, the English top-flight is hoping to ease fears the new rules could be misused for a competitive advantage.

FIFA have also approved a trial of concussion substitutes for the Club World Cup in Qatar next month.

Football's authorities have come under increasing pressure to show a more proactive attitude to head injuries.

Benfica defender Jan Vertonghen revealed last month that he suffered the after-effects of a concussion for nine months, despite continuing to play.

Vertonghen suffered a blow to the head while playing in a Champions League semi-final for Tottenham against Ajax in 2019.

He played on for a brief spell, but had to be helped off moments later and was seen vomiting on the side of the pitch.

The Belgian returned and played just a week later, but suffered from dizziness and headaches until football's stoppage due to the coronavirus pandemic in March allowed him a prolonged rest to recover.

A study, led by consultant neuropathologist Dr Willie Stewart of Glasgow University and published in 2019, found that former footballers are approximately three and a half times more likely to die from neurodegenerative disease than the general population.

A number of England's 1966 World Cup winning team have been affected by such diseases in later life. Jack Charlton and Nobby Stiles died from dementia last year, while Manchester United legend Bobby Charlton has also been diagnosed with the condition.

A host of former rugby union internationals announced in December they are planning legal action against their sport's authorities over the consequences of concussion.