Apologies if this has been mentioned already - but check out they symptoms of Cyclists Palsy also known as Handlebars Palsy - again, to do with trapped nerves - this article explains it- others are also available on t'interweb:
http://www.elitesportstherapy.com/Cyclists--Palsy
Early sympoms are tingling/numbness.
Not mentioned on NHS direct or Wikipedia, but a medical condition nevertheless, and one to do something about. Sadly, a young woman died a couple of years ago round here when cycling, possibly as a result of her hands seizing up due to palsy: the coronor referred to it in his summing up. Report here:
http://www.bbc.co.uk/news/uk-england-devon-27448972
It was a terribly sad case, and if reading about what happened to her persuaded just one person to get checked out and prevent another occurrence, then maybe that would be one tiny scrap of consolation.