Long ago, SB mentioned that Sally Beauchamp, whom VN read about in West's Psychical Research Today, has the same name as the tutor of Kinbote's boyhood pal, Oleg. The following is the best account I have read, and it highlights how several personalities may interact in ways that seems roughly similar to the way the Shade-Kinbote-Gradus personalities interact under a theory of multiple personalities. This is from William Henry Salter's Zoar:

 

 

Right before the Beauchamp story, Salter talks about Ansel Bourne and notes that his return to his original personality occurred at the (presumably imagined) sound of a gunshot. John Shade, I believe, entered his new personality to the sound of a gunshot.

 

Matt Roth