I remember an article about an architect who lost his mental visualization, he had no problem performing mental rotation puzzles. Can't seem to find the article, unfortunately. In general, from reading a lot about this a few years back (when I found out "seeing a picture in your mind" is not just a metaphor...) it seems aphantasiacs don't have any difficulty with any kind of mental task.

Edit: here's the article, rotation stuff is in the 2nd paragraph on page 2.

http://web.archive.org/web/20120615154334/http://discovermag...

i am a mathematician and i have aphantasia. i am pretty certain that not having to train not to rely on visual intuition was very helpful for getting into the kind of mathematics i do (set theory and very transfinite topology). on the other hand i am always completely amazed by what some people can "see" and feel in 3 or 4 dimensions. i have absolutely no access to this kind of spatial reasoning.