It's an interesting question, since I belong to this group as well (rather a lot > 150, before falling ill) and so was my ex (146) who also got ME, 10 days after me. (That is, precisely speaking, in our case: Epstein-Barr.) There also is in my case a link to appearing much younger than I am, that some link to neurasthenia, whereas I link it rather to neoteny (and high intelligence).
In any case... there is of course a selection bias i.e. the more intelligent are more likely to write, to protest etc. But regardless of that, what I do find VERY heartening is that on this forum there clearly are a number of highly gifted, quite sane, quite ill people, and this should give ALL of us (with ME, on the forum) real opportunities that none of us had or have as individuals argueing alone, and trying to support ourselves against bureaucratic or medical dumbos just by ourselves.
I think this needs some coordinating in the none too far future, and it might be a good idea to make a poll or set up a table with educational levels reached, and subjects studied. This may allow this forum to start acting in some ways as a coordinated group, at least with regards to reactions to publications about ME.
But as far as I am concerned, this is a first for me with ME in over 30 years:
A group of clearly intelligent, clearly sane, clearly well-educated people with the same disease as I (seem to) have - which should give all concerned with ME some hope, and which we (on the forum) should also try to preserve. (By which I mean e.g.: Back up the forum, the site, and the addresses of members, so that the Phoenix can rise again if the particular virtual incarnation it has now might collapse for some reason, such as bugged software, failng providers etc.)
More personal, about cognition:
It has for a long time seemed to me - from before I got ME - that I am smart in part because I can add a level or 2 or 3 above my normal functioning, e.g. for doing maths (or speaking in rhymes at normal speed - that sort of intensive processing). This got worse with ME, but varies, so my own guess is that it may be correlated with blood flow to the brain. (It certainly is correlated with feeling bad.) And like others I may have problems recalling words and names, and also completely loose the thread of a conversation, indeed specially when on the phone or feeling really tired or miserable.
Finally, it does vary and has varied these 30+ years, and is most strongly correlated with my general degree of health/illness. Thus, I spend May of last year doing maths at high speed, which I wasn't able to do for years, for a month or so and then got "too fatigued" again to keep going on with it.
Anyway... the somewhat hopeful thing for others with ME (who are or were bright) is that, in my case at least, and in the case of others too, it seems. while I am evidently less intelligent than I was before falling ill, I have not progressively deteriorated; the lack of brightness was strongly correlated with lack of health; and it seems - but that is a guess, and may not be true for others - to have to do more with blood flow than lesions. (Here my reason is as explained: It is reversible, namely when I feel otherwise tolerably well.)