Ian Crofton writes in 50 world history events you really need to know, regarding division of labour in pre-historic hunter-gatherer societies:
Before the coming of farming there was some division of labour. In hunter-gatherer societies the women usually did most of the gathering and the men most of the hunting, while certain individuals, sometimes with some form of disability, became shamans.
Because the book is a short synopsis for a layman audience, there isn't a citation for the evidence to support this claim.
My question is, how do we know that some disabled people became shamans in pre-historic, hunter-gatherer societies?