The International Football Association Board had been urged by the Premier League to trial a temporary substitution to allow players with head injuries to be assessed.
IFAB will instead continue with permanent substitutes which FIFA president declared the "risk-free" approach but according to Headway Chief Executive Luke Griggs they are in danger of losing credibility in the area of brain health.
"FIFA president Gianni Infantino claims football is 'making player health the main priority' by extending the trial of permanent substitutes," Griggs said in a statement.
"But this system has repeatedly failed to protect players as it relies on either medics making an immediate judgement or for a player to risk exacerbating their brain injury by playing on for 10 to 15 minutes to see how they get on.
"FIFA's claim that the current system represents a 'zero risk' approach is not supported by the repeated failures to take an 'if in doubt, sit it out!' approach to concussion.!"
The permanent concussion substitutes rule was introduced in the Premier League at the start of 2021 and means that a team can replace a player with a suspected head injury without it counting towards their allocation of substitutes.
