Proprioreception probably started out as a mispronunciation of proprioception, just as orientate did.

Or it could have been that proprioception probably started out as a mispronunciation of proprioreception, just as adaption did.

Speaking as one who'd been using the term proprioreception in the early 60s (in Oz) I suspect there are as many regional traditions in such matters as there are notions of tradition.

Perhaps there is a song in the experiment that originally proved the existence of the concept. If you put a pair of specs on a person, with the lenses skewing the line of sight so that a bearing of 30 degrees to one side is seen as "straight ahead", the brain takes about half an hour to accommodate to the change. The subject wearing them would be able, after that half hour, to walk around objects with the same speed and lack of walking into them as they had when walking normally before wearing the specs.

The experimenters then repeated the experiment with able-bodied people restrained in wheelchairs. They first accustomed their subjects to using wheelchairs without the prism spectacles until they could travel successfully between the objects. When they fitted the prisms, it still took the subjects about half an hour before they could manouevre the wheelchairs between the object successfully.

They then removed the wheelchairs and, with the subjects still wearing the prism specs, found that the brain still needed another half hour or so for the brain to become accommodated to the info produced by the proprioreceptors in the lower limbs.

There's got to be a song in there somewhere.

Cheers, Rowan