This syndrome occurs when the capillaries narrow in the body reducing blood flow to the extremities. It generally occurs along with an underlying health issue but can also appear on its own. There are a variety of triggers which will influence the degree and severity of attacks.
It is a form of cognitive dysfunction that can occur as an overlap symptom of illness, injury, pregnancy, or alongside the other side effects of aging. Brain fog feels much alike the cloudy dopey feeling of having a bad case of the flu or the cognitive issues that come from being extremely tired.