Thanks for this question. I am also interested in such issues. But Moodle is a simple LMS at its core. I dont see any help it can provide by itself. So the question need to be posed in terms of technology solutions, organisational support, etc. Perhaps, someone can also throw light on what is the connection between being deaf and being good at maths.
There are findings concerning deaf students abilities for problem solving in maths, in particular, algebra. For instance, deaf students have reported to have problems with transitivity. A current project at RIT is investigating such issues: http://www.ntid.rit.edu/research/projects.php
Computing the transitive closure of relations seems to be challenging also in domains different than maths, such as, story comprehension: correlating events in stories/texts through (also short) temporal chains can be a challenge. See the results of the TERENCE project: .