I found this confirms my belief that this problem is accessible through the neck. I get relief that allows me to tricycle in the hot sun, from a head-cooler (do-rag soaked in water) under my helmet. and a hydrophilic-crystal-filled neckerchief. This is also soaked in water, but retains it better than the do-rag.
What does this mean? I think it means the blood that's going through these areas is not going fast enough to be cooled by skin sweating, that the processes in the endothelium and in the blood which should expand the veins aren't doing it, so that blood doesn't go fast enough, or that there is a stenosis which doesn't allow the blood to go fast enough, or that autonomic nerves which should control the blood supply be expanding the veins, aren't doing it because there is nerve damage.
I favour the not-autonomic-nerve scenario because this process seems to be automatic regardless of proximity of many nerves (such as in the wrist, which cools when dipped in cold water. I think this has to be quick, and cannot wait for signals to get to the brain and back.
I find that if a solid body part gets too hot (like my skull or my spine) it will take an awfully lonng time to cool, and my spasticity that results will take a long time to go away. So the protoection of cooling the neck prevents the spine from getting too hot, maybe?
"Try - Just A Little Bit Harder" - Janis Joplin
CCSVI procedure Albany Aug 2010
'MS' is over - if you want it
Patients sans/without patience