Originally Posted by
bpcyclist
Thank you. You allude to a very good point, which is, the difficulty of actually carrying out a properly designed helmet safety study in humans. Ideally, we would prefer to see a randomized, placebo-controlled, double-blind study, because they are generally the gold standard. But that is just never going to happen in any compassionate, sensible country. For some users, that would be like agreeing to enter a study where they could be randomized to no seatbelt or no air bag or no antibiotics for pneumonia. Some people just will not do that, understandably. I you are perfectly healthy and love your WaveCel or MIPS or SPIN, you are not going to take a chance on not having your helmet on in the event you crash in the name of science, regardless of how noble and selfless you may be. So, then, I suppose we would probably be stuck with a retrospective look at accident crashes. But how does that get done? I live in one of the most pro-cycling cities on the planet, but we certainly don't have any kind of registry of accidents and victims. There is no mandatory reporting. Does your city, state, province, or prefecture have such a registry?
I would think that mandatory accident reporting would be almost a requirement in order to collect enough decent data for a retrospective study to have any kind of power. Maybe that will happen in some progressive and thoughtful locality somewhere. Until then, we are stuck with just random reporting of random events. And that isn't getting us any closer to the truth.
Trials in this area would not be placebo or sham controlled, they would be comparative effectiveness trials and these are done all the time. The ethical threshold is whether there is “equipoise,” that is, an honest lack of knowledge, on the relative effectiveness of the helmet types. The big problem with this kind of research is the statistical difficulty of proving differences in effectiveness between two effective treatments.
A more effective, but also ethically fraught, way to answer the question is with a primate concussion model. Essentially everything we know about the mechanism of concussion today came from one lab at Penn, which was shut down in the 1980s for mistreating their animals. If it were decided that the social need was high enough and that the research could be done in an ethical manner, this would be the way to go.
Registries are great and the need is obvious, but concussion is hard to characterize with a single, cross-sectional, look, and there are hundreds of helmet types out there.