"According to new research, a predisposition to high levels of absorption in tasks, unusual auditory experiences in childhood, and a high susceptibility to auditory hallucinations all occur more strongly in self-described clairaudient mediums than the general population."
Click on the link below for the latest research on clairaudience, the power or faculty of hearing something not present to the ear but regarded as having objective reality.
I have no idea why Paul had "visions" of Jesus, do you?