Brain fog is caused by many things, and one such thing that most ignore or fob off is the effect of wireless technology on CFs and ME sufferers. Since the proliferation of the airways with microwave non-ionised radiation in a form of electrosmog soup the increase of illnesses and syndromes are noted. If you are in such an environment, then you are possibly electro hyper sensitive (EHS) to electromagnetic radiation (EMR) and electromagnetic fields that are emitted from mobile phones and towers, Wi Fi, DECT phones, and wireless computer/modem/router.
These are some of the symptoms of EHS:
If I remember my physics course (many decades ago), the only way wireless signals could harm a normal, healthy person would be through heat, and that would be only if the person was too close to a transmitter. Before I became disabled with CFS I worked on a military project that involved training people in RF hazards, so I learned a bit about how this works, with normal people who don't have high metals.
I believe the problem is that if a person has an unnaturally high level of metals, which will be the case with poor methylation and low glutathione combined with exposure to toxic metals, then there can be different types of magnetic or radiation effects, disruptions like you mention. And as more and more people get sick with toxic metals and develop methylation blockages, probably EHS will increase.
I had severe EHS at one time. My EHS was so bad I had to get rid of my electric clock, and limit computer use, and I could not be in the same room with anyone using a cell phone. This is mostly cured with methylation support, mold avoidance and rehydration therapy (an oral rehydration solution). And I did also take EDTA for awhile. I am able to tolerate EM/RF now, can even use a cell phone again, although some newer computers are still a problem if I am too close to the CPU or use them too long.
Anyway, I believe that high metals (in the brain or CNS perhaps) are a primary factor in EHS. Not sure why the mold issue made my EHS worse, probably that was just a general health and general sensitivity improvement.