[pirogen]

I went from hyperphantasia as a child to complete aphantasia in my early teens. When I was <= 7 y.o. my favourite past time was playing and directing vividly realistic movies behind my closed eyelids. Sometimes I could even visualize things with my eyes open, creating a kind of "extended reality" with imagined things or creatures interacting with real ones. This ability started to gradually disappear around the time I went to school, and now I'm completely unable to visualize anything (other than occasional involuntary hypnagogues before falling asleep).