Wish I knew! The only thing I know is--it's the best term for how one feels when your head feels 'full' and makes you feel drugged--when you aren't! And you have trouble thinking clearly--especially trying to carry on with reading, TV, talking at the same time--multi-tasking (as we once were able to do). Seems I have trouble 'concentrating' on TV, a phone conversation or my husband talking and TV on or the phone rings and our conversation hasn't ended and I am trying to listen and comprehend both. A very frustrating 'mind boggling' goes on and makes me very anxious! If that is brain fog--I have it for sure. The MM is a big cause of it--as it adds anxiety which makes it worse. Others have commented here--so hopefully they will weigh in!
I was told that brain fog is an exhaustion caused by a disease effecting your body. Your body is working overtime with any illness, especially chronic, and that the over working makes it harder for your brain to focus on things, and remember things. I don't know how accurate that is, but all I know for sure is brain fog is a super hard symptom to deal with, and I hate it a whole bunch.
My theory is this; Your computer has finite resources of RAM. When you are multitasking and downloading a large file it slows the machine down. Your brain is your body’s computer. It is constantly performing background tasks to keep your body stable and upright. You have a condition that places additional load on the brain’s RAM in that it is having to compensate for false signals from your ‘broken’ vestibular system. As a result you have less RAM available than a healthy individual. At times when demand is high your brain/computer struggles to cope and this leads to a slowing of performance aka “brain fog”. Unfortunately we can’t upgrade, but we can do a lot to reduce the demand by looking after ourselves, reducing stress and boosting our immune systems.
My doc said pretty much the same as yellow. You only have so much brain power, and with a balance disorder your brain is devoting much more energy than typical just to keep you upright. When my symptoms flare is really the only time I notice the brain fog. It also makes me very tired. When I get tired, I don't fight it anymore. Sleep seems to help the most. Reduce stress elsewhere in your life where you can, it seems to help too.
Agree with Bodama about sleep. Sleep sort of resets my brain. Well, that's obvious I suppose. But for us MD sufferers it's especially necessary. Even short naps help. Problem is I'M SICK OF NAPPING.