Yes, I have had this brain fog you speak of. When my auto immune disease first started. It was like trying to think through peanut butter. My limbs,my arms, my legs felt like lead. I had to tell myself, pick up your leg, and put it in front of the other. For me it started as an allergic reaction to penicillin, and escalated from there. The more the doctors tried to help the worse it got. Before it was all over I was suffering from siezures, They where trying to stop them. Until I discovered holistic medicine. You have to understand, it doesn't happen overnight, but healing will take place, it just takes time, and the right supplements. For me it was a combination of different things. 1. l-glutamine, to eliminate brain fog, and for hypoglycemia.2. Trytophan, to replace lost serotonin.3. melatonin for insomnia. 4. Gaba for anxiety, from the hypoglycemia, which also causes brain fog. 5. A good multi vitamin, and better diet, high in protein and fat. Complex carbohydrates, protein and fat, help to control hypoglycemia, and to balance insulin levels. Such as peanut butter, and avocados. 6. Balance of hormones, at the time I was also going through menopause. Which, if you are predisposed to insulin control problems, it can get worse in mid life. You have to give up garbage food. Every bite you take has to be thought of as medicine. Eat as close to its original form as possible, referred to as a whole food, in most areas of holistic medicine.
Dr. Teitelbaum refers to this as the shine protocol.