I am curious how polyphasic sleep preferentially affects consolidation of declarative or procedural memory. (That is: does it improve procedural memory, affected by REM sleep, at the expense of declarative memory, consolidated by SWS?)
I don't think anybody ever looked at that. To be honest I don't even think there are so many studies on polyphasic sleep, tout-court. There's quite a lot of literature on people doing work shift, though, and we know they have plenty of troubles.
As far as the memory part: the link you talk about (declarative NREM vs procedural REM) is very intriguing and many researchers are looking into sleep and memory in general. Yet, we are not at a stage where we can actually make so clear distinction: most work is still very very correlative.
