The fact that the dementia of Neimann Pick is caused by cholesterol buildup in the brain is very, very interesting to me. I've always wondered if actual structural "brain damage" (as in, say, demyelination) could fluctuate the way my "brain fog" does, from day to day & sometimes hour to hour. (btw totally agree it's a silly term, "brain fog" - useful shorthand, but way too cutesy to capture the, well, horror of losing your mental faculties) Found an interesting piece on the HIV/cholesterol connection here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1629035/ I guess the next question that occurs to me is, what is the nature of the known dementia that comes with AIDS? Could it be cholesterol-related? Found a wiki on it: http://en.wikipedia.org/wiki/AIDS_dementia_complex No mention of cholesterol there, though it doesn't sound like they've firmly established the cause. A reach, probably.