The Ascendant: Hierophant Trilogy Book One

Dr. David Keating is in a coma, his consciousness fractured into an infinite number of fragments, descending into a netherworld where nothing should exist. His condition is brought on through self-experimentation, an attempt to use his knowledge and skills to 'cure' himself of his afflictions.

In desperation, he reaches out from the void to a woman thousands of miles away, hoping she can save him. In calling out, Keating has unwittingly created a connection that does far more than call for rescue - the bond between them could create the next stage in human evolution....

The Ascendant.