maybe he ate one too many mushrooms behind Iwama shrine
I have been in the presence of a few mediums who use auditory links to spirits.i have also had an experience with of trance spirit doctor ie a man who adopted the persona of a dead doctor.
Since the Kami are in a sense a type of spirit, it may well be that O Sensei might have been a medium?. cheers, Joe.
Ps Lets not quote the old joke here!!