Typically, the local Bishop convenes a committee of theologians, exorcists, scientists, etc. to conduct studies of certain mystical occurrences. Such investigations can take decades to complete. They subject the visionaries to various tests, for example: while in ecstasy, subjecting them to EEGs, heat applied to their bodies, even things such as pin pricks, ocular tests .....and much more in attempts to determine if their ecstasies are authentic. They also look for theological errors. They subject them to tests of obedience, and more.
At the end of such an investigation, the Bishop, renders a decision as to whether the messages conveyed are "worthy of belief", or "not worthy of belief". Until a decision has been rendered the mystical occurrences remain in the "yet to be approved" category. [Latin titles are used, in fact.].
It should be emphasized that even if mystical occurrences, and the messages conveyed, are declared to be "worthy of belief" THEY ARE NOT PART OF THE FAITH, AND AS SUCH ARE NOT REQUIRED TO BE BELIEVED.
During the last 160 or so years, there has been an explosion of private prophecy. So much so, that a very small fraction will ever be studied.
For some that have been approved as worthy of belief, see:
After the Warning and
The Whore of Babylon at
http://www.call2holiness.org/era-of-peace.html