Them, 1st off CFS = Cerebrospinal fluid not cervical 
Second: I have had the displeasure of dissecting several brain tumours so I am aware of the texture of the brain tissue, I am also aware of the effects of swelling on brain damage and the relationship between heat and swelling... I also think that it is a great idea to cool the head upon impact.
I will be addressing this comment:
Firstly, the gel pack has a fluid viscosity and will not impede the energy absorbsion protection afforded by the EPS (expanded polystyrene).
The issue that I have is that the cooling fluid gel pack is on the inside of the polystyrene layer. Consider the last time that you jumped belly first into a swimming pool. It hurt because the water is incompressible and the viscosity is such that it could not be displaced fast enough to allow you to decelerate slowly, your energy was transferred quickly to the water. At a high enough speed, you may as well be landing on concrete.
Given that, consider the gel pack on the inside of the helmet: this is a very incompressible fluid and given the nature of a gel, it is also very viscous. It would not be displaced fast enough and it would not be compressed during a high energy impact (i.e. high speed). It would effectively be like riding with a four layered helmet:
A hard incompressible outer layer (i.e. shell)
A soft compressible centre layer (EPS layer)
A hard incompressible inner layer (the gel during a big enough impact)
Soft foam padding
It may be that energy is simply transferred directly from the head to the polysytrene, the polystyrene compresses in the normal way and the head decelerates in the normal fashion. However, what if when the gel acts as a hard incompressible layer additional injuries are sustained as the head hits the viscous gel packs prior to compressing the EPS.
Nobody would ever suggest that we all fit hard plastic liners to our helmets however these gel packs upon impact would act in a similar fashion.
If you don't mind me asking, are you one of the researchers developing this product?
Posted: 08/12/2009 at 19:46