There was a group of doctors out on Long Island several years back who were trying to get funding for a study on potential links btwn. lyme disease and ALS. Why? Bcse of 18 ALS patients they treated, exactly half also tested positive for lyme by PCR and titer. I don't know if they ever got funding, but I know that there have been many anecdotal cases of ALS patients testing positive for lyme. Whether that means untreated lyme can eventually lead to ALS, or if it means some tertiary lyme patients have been misdiagnosed with ALS, I couldn't say. It's intriguing in the context of this article, though, since soccer players spend lots of time out in parks, fields, etc.
Even tho it was ruled out by the doctors, my mother in law always felt like Lyme disease was somehow related to her ALS. In the reading I've done, the docs seem to pooh pooh the idea of there being a connection.