In response to Chasm54's questioning of your assertions on the subject of helmets having being shown to reduce brain injury you have (either knowingly or ignorantly) confounded head injuries in general with brain injuries in specific and, further, made the extreme claim that helmets have been shown to lessen rotational brain injuries.
Originally Posted by proileri;
We also have good data from hospitals - from crashes where injuries are serious enough to ward a hospital visit - and these show that helmets lessen the head and brain injuries when the crash is severe. I think these are pretty good indicators - it's hard to imagine a person getting serious brain damage in a crash and not be taken to a hospital immediately or soon after! In these studies, rotational brain damage is included in the "serious brain damage" group
In support of these statements you advance a short extract posted above from a study as a "better" (for some unknown value of better) study:
Originally Posted by
proileri
yet this very study has low sample size associated with it and also includes in the very abstract cited a possible alternate explanation for the correlation between helmet absence and injury:
Non-helmeted cyclists were more likely to display risky riding behaviour, however, were less likely to cycle in risky areas; the net result of which was that they were more likely to be involved in more severe crashes.