Image source, Getty ImagesImage caption, Ex-player Kevin Henry took the NFL to court over the fund earlier this year.

The NFL has agreed to end race-based testing for compensation claims made by ex-players suffering from dementia, documents filed with a US court show.

It follows revelations that the previous testing system was based on a formula that assumed black players have a lower level of cognitive function.

This "race-norming" made it harder for black players to prove they suffered from injuries linked to their careers.

The draft agreement means thousands of retirees may qualify for compensation.

The 46-page document pledges that: "No Race Norms or Race Demographic Estimates – whether Black or White – shall be used in the Settlement Program going forward."

Around 1,435 players, many of whom are black, will now be given the chance to have their tests rescored, or in some cases, seek a new round of cognitive testing.

A panel of experts will also develop a new standard that will apply to all future tests under the scheme, any claims that have not yet been ruled on, and all claims that are currently on appeal.

The vast majority of the league's players – over 60% of living retirees and 70% of active players – are black.

Under race-norming, the NFL compared a player's cognitive test scores with the supposed norm for his demographic group. Under the methodology, black players are assumed to possess a lower level of cognitive function than the average white player.

But attorneys say the standard means that in order to qualify for compensation, the average black player must demonstrate a greater level of cognitive decline than a white counterpart.

While the NFL has defended the practice in the past, saying its standards "relied on widely accepted and long-established cognitive tests and scoring methodologies," in June it announced that it intended to discontinue the practice.

The NFL's concussion fund has paid out $856 million (£600m) for five types of brain injuries, including early and advanced dementia, Parkinson's disease and Lou Gehrig's disease (also known as ALS) since it was established in 2013.

However of the roughly 2,000 men who have applied for dementia awards under the scheme, just 30% have been approved.

Two former black players, Kevin Henry and Najeh Davenport, who were refused payouts under the scheme, launched a civil lawsuit.

But a judge dismissed the lawsuit in March and ordered the NFL to negotiate a settlement.