Replying to Multi-impact Helmets vs. Single Impact Helmets

So, I've read a couple of times that helmets designed to receive multiple impacts before being replaced are less effective at protecting you from concussions and more serious brain injury in more serious collisions. I would greatly appreciate if someone could direct me to a study that suggests that this is the case.

I'm in the process of acquiring a new helmet and want to get my facts straight before making a decision.

Sorry if this has already been addressed in another thread, I couldn't find said thread if it does in fact exist.

Thanks!