Bilingualism is good for you

At least according to this study from Canada, which indicates that "the lifelong use of two languages can help delay the onset of dementia symptoms by four years compared to people who are monolingual". This is excellent news: although it's not entirely clear how they define "bilingual", which I usually take to mean someone who grew up from an early age with (at least) two native languages, I'd guess here people like my humble self, who live permanently and actively in a bi- or multilingual environment are also included. As I have to deal with three (!) languages on a daily basis, does that give me an extra 8 years before my brain dissolves into an incoherent mush?

(The disadvantage of having several languages on the go is, however, that they tend to get a little confused with each other. I never was a particularly brilliant speaker anyway - during bad times a borderline stutterer - and have a nasty tendency to trot out sentences with a distinctly German structure; or realise that's what I'm about to do and hastily backtrack, which makes me sound like I have a speech impediment. And I have lost count of the number of times I know exactly what I want to say, but can't recall the words in the language I want to say it in. Wouldn't surprise me if in my dotage I get shut away in some institution because although my mind is in full working order I appear unable to express myself coherently).