I'm working on a committee to address accessibility at my institution, and we have done a lot of experiments with screen readers on a lot of different documents.
So far we have concluded that
pdf documents, no matter how they were generated (
LibreOffice, etc), are not screen-reader-accessible when they contain mathematical content.
We have found, particularly for documents that have mathematical content, the best way by far is to convert the
.tex file into an
html file that has
MathML content using, for example,
htlatex myfile.tex "html,mathml"
and then have the screen reader act on the
(x)html file. Interestingly, we have found that while Firefox can render
MathML easily, the screen reader (we use Jaws) works better with Internet Explorer with Mathplayer.
MathML greatly improves accessibility of mathematical documents. Indeed, from this format one can either go down the screen reader or the Nemeth Braille route. Some questions that you might also like to have a look at: