This sparks something I have always been fascinated by, hopefully someone can illuminate this for me. If someone was born with profound blindness, or deafness

This sparks something I have always been fascinated by, hopefully someone can illuminate this for me. If someone was born with profound blindness, or deafness or any profound lack of sense - what do they see in their heads? Or hear? I hear a version of my voice in my head, but some people have no inner dialogue at all, or even no ability for inner imagery. What does the brain do in these situations?