I was able to use this option Hide Board title on one forum, but I could not do it with another forum, until I found the solution in this thread and applied it to the second forum. It worked.
Google typically still does display and use text on a page that is visibility:hidden and/or display:none in their search results. This isn't guaranteed but the use of css options to hide text does not block that same text from inclusion in search results and SEO factoring as far as Google is concerned.