Regex search in PDF reader

I am using zathura, as I enjoy its minimalist approach, but I would also switch to mupdf or anything else if this would solve my problem. I need to highlight every word (in PDF and epub documents) one by one from start to finish because I can concentrate better on the text if I have some kind of motion in it. My approach would have been to perform a regex search that matches every word, but neither zathura nor mupdf support regex in searches. Is there a way to do this? I would try to fork zathura but to be honest I don't really want to spend that amount of time if there is another minimal Gnu/Linux compatible document viewer that does what I need. And if there is any way to use terminal tools like pdfgrep for highlighting the results in zathura that would also do the job.