well just speaking from personal experience.
I read several of those claims years ago. And personally I find it BS
Those same reports claim that full face helmets reduce your hearing capability.
Now honestly how many of you have been driving down the road and stuck your head out the window.. can you hear ANYTHING besides the wind ripping by?
I would only wear a full face Snell approved helmet.
Find out what Snell is and why you want a Snell certified one
http://www.smf.org/ The fact is ANY time you go down you take the risk of suffering severe to critical injuries.
Since I have gone down way too many times and enough to know what the effects of various types of wrecks will have on your body.
If some statitician wants to claim that a full face slightly increases my chance of a neck injury. In lieu of saving my face. Then I'll take that risk.
Riding a motorcycle is just that, a risky decision. I say use your common sense and think about the effects of jumping out of the back of a pick up at 30, 50 or 80MPH and then YOU decide what kind of safety equipment you would prefer.
I'll take my chances that the glove I wear will snag on something and rip my hand off.
I'll take the chance that the leathers I wear will allow me to slide 30 feet further than my skin would, putting me at risk of hitting something 30 feet beyond the point my bare skin would have stopped me.
I'll take the risk that my head will snap back a bit more due to the weight of my helmet giving me more whiplash than I would have recieved without it. I like my ear.. I think I'll protect it.
I'll take my chances.