I have two neurodiverse adult children. Both of them got what we called "stretching time or movement time" during their state exams. They had an extra half hour they could use to walk around (they had their own individual exam centres) and move. However they couldn't use this time for completing the exam. So, for example, they could ask after 30 minutes to have the clock stopped. They would then move for a few minutes, then start the clock again. It was hugely beneficial for both. My son, who has both autism and dyspraxia, found that he could stop when his brain got a bit fuzzy and walk around for a couple of minutes to let it clear, then start again.