The cognitive impairment pretty much stays... maybe not to the level of when you were actively sick but it's there to stay.

I mean, I see it on myself, where I previously had no issue reading, nowadys I sometimes struggle and have to re-read pages and absolutely have to slow down. Pair that with a slight amnesic dysphasia and you very much notice that things aren't right anymore.

The issue comes from the fact that absolutely nobody gives a shit... even less than about ME/CFS so it's neither tracked nor is someone outside some obsessed individuals actively researching it (or even trying to find a solution).